Design and application of wireless signal strength measurement system on the near-ground
RTTE无线WIFI现场测试记录
1 2 3 3.1 3.2 4 5 6 6.1 6.1.1 6.1.2 6.2 6.2.1 6.2.2 6.3 6.3.1 6.3.2 6.4 6.4.1 6.4.2 6.5 6.5.1 6.5.2 6.6 6.6.1 6.6.2 目的 ............................................................................................................................................ 4 测试设备的技术参数 ................................................................................................................... 4 利尔达 LSD4WF-2MD05101 模组 .................................................................................................. 4 WIFI 模块的相关知识 ................................................................................................................................. 4 利尔达 WIFI 模组参数设置 ........................................................................................................................ 5 使用设备及工具 .......................................................................................................................... 7 法规要求 ..................................................................................................................................... 7 射频发射测试 .............................................................................................................................. 8 RF OUTPUT POWER (射频输出功率)................................................................................................................ 8 测试要求 ................................................................... 8 测试结果 ................................................................... 8 POWER SPECTRAL DENSITY (功率谱密度) ............................................................................................... 8 测试要求 ................................................................... 8 测试结果 ................................................................... 9 DUTY CYCLE, TX-SEQUENCE, TX-GAP ...................................................................................................... 9 测试要求 ................................................................... 9 测试结果 ................................................................... 9 MEDIUM UTILISATION (MU) FACTOR .......................................................................................................... 9 测试要求 ................................................................... 9 测试结果 ................................................................... 9 ADAPTIVITY (自适应测试).......................................................................................................................... 10 测试要求 .................................................................. 10 测试结果 .................................................................. 13 OCCUPIED C HANNEL BANDWIDTH (占用信道带宽) ............................................................................... 13 测试要求 .................................................................. 13 测试结果 .................................................................. 13
SIGNALINTEGRITY（信号完整性）外文翻译
SIGNAL INTEGRITYRaymond Y. Chen, Sigrid, Inc., Santa Clara, CaliforniaIntroductionIn the realm of high-speed digital design, signal integrity has become a critical issue, and is posing increasing challenges to the design engineers. Many signal integr ity problems are electromagnetic phenomena in nature and hence related to the EMI/EMC discussions in the previous sections of this book. In this chapter, we will discuss what the typical signal integrity problems are, where they come from, why it is important to understand them and how we can analyze and solve these issues. Several software tools available at present for signal integrity analysis and current trends in this area will also be introduced.The term Signal Integrity (SI) addresses two concerns in the electrical design aspects – the timing and the quality of the signal. Does the signal reach its destination when it is supposed to? And also, when it gets there, is it in good condition? The goal of signal integrity analysis is to ensure reliable high-speed data transmission. In a digital system, a signal is transmitted from one component to another in the form of logic 1 or 0, which is actually at certain reference voltage levels. At the input gate of a receiver, voltage above the reference value Vih is considered as logic high, while voltage below the reference value Vil is considered as logic low. Figure 14-1 shows the ideal voltage waveform in the perfect logic world, whereas Figure 14-2 shows how signal will look like in a real system. More complex data, composed of a string of bit 1 and 0s, are actually continuous voltage waveforms. The receiving component needs to sample the waveform in order to obtain the binary encoded information. The data sampling process is usually triggered by the rising edge or the falling edge of a clock signal as shown in the Figure 14-3. It is clear from the diagram that the data must arrive at the receiving gate on time and settle down to a non-ambiguous logic state when the receiving component starts to latch in. Any delay of the data or distortion of the data waveform will result in a failure of the data transmission. Imagine if the signal waveform in Figure 14-2 exhibits excessive ringing into the logic gray zone while the sampling occurs, then the logic level cannot be reliably detected.SI ProblemsT ypical SI Problems“Timing” is everything in a high-speed system. Signal timing depends on the delay caused by the physical length that the signal must propagate. It also depends on the shape of the waveform w hen the threshold is reached. Signal waveform distortions can be caused by different mechanisms. But there are three mostly concerned noise problems:•Reflection Noise Due to impedance mismatch, stubs, visa and other interconnect discontinuities. •Crosstalk Noise Due to electromagnetic coupling between signal traces and visa.•Power/Ground Noise Due to parasitic of the power/ground delivery system during drivers’ simultaneous switching output (SSO). It is sometimes also called Ground Bounce, Delta-I Noise or Simultaneous Switching Noise (SSN).Besides these three kinds of SI problems, there is other Electromagnetic Compatibility or Electromagnetic Interference (EMC/EMI) problems that may contribute to the signal waveform distortions. When SI problems happen and the system noise margin requirements are not satisfied – the input to a switching receiver makes an inflection below Vih minimum or above Vil maximum; the input to a quiet receiver rises above V il maximum or falls below Vih minimum; power/ground voltage fluctuations disturb the data in the latch, then logic error, data drop, false switching, or even system failure may occur. These types of noise faults are extremely difficult to diagnose and solve after the system is built or prototyped. Understanding and solving these problems before they occur will eliminate having to deal with them further into the project cycle,and will in turn cut down the development cycle and reduce the cost[1]. In the later part of thischapter, we will have further investigations on the physical behavior of these noise phenomena, their causes, their electrical models for analysis and simulation, and the ways to avoid them.1. Where SI Problems HappenSince the signals travel through all kinds of interconnections inside a system, any electrical impact happening at the source end, along the path, or at the receiving end, will have great effects on the signal timing and quality. In a typical digital system environment, signals originating from the off-chip drivers on the die (the chip) go through c4 or wire-bond connections to the chip package. The chip package could be single chip carrier or multi-chip module (MCM). Through the solder bumps of the chip package, signals go to the Printed Circuit Board (PCB) level. At this level, typical packaging structures include daughter card, motherboard or backplane. Then signals continue to go to another system component, such as an ASIC (Application Specific Integrated Circuit) chip, a memory module or a termination block. The chip packages, printed circuit boards, as well as the cables and connecters, form the so-called different levels of electronic packaging systems, as illustrated in Figure 14-4. In each level of the packaging structure, there are typical interconnects, such as metal traces, visa, and power/ground planes, which form electrical paths to conduct the signals. It is the packaging interconnection that ultimately influences the signal integrity of a system.2. SI In Electronic PackagingTechnology trends toward higher speed and higher density devices have pushed the package performance to its limits. The clock rate of present personal computers is approaching gigahertz range. As signal rise-time becomes less than 200ps, the significant frequency content of digital signals extends up to at least 10 GHz. This necessitates the fabrication of interconnects and packages to be capable of supporting very fast varying and broadband signals without degrading signal integrity to unacceptable levels. While the chip design and fabrication technology have undergone a tremendous evolution: gate lengths, having scaled from 50 µm in the 1960s to 0.18 µm today, are projected to reach 0.1 µm in the next few years; on-chip clock frequency is doubling every 18 months; and the intrinsic delay of the gate is decreasing exponentially with time to a few tens of Pico-seconds. However, the package design has lagged considerably. With current technology, the package interconnection delay dominates the system timing budget and becomes the bottleneck of the high-speed system design. It is generally accepted today that package performance is one of the major limiting factors of the overall system performance.Advances in high performance sub-micron microprocessors, the arrival of gigabit networks, and the need for broadband Internet access, necessitate the development of high performance packaging structures for reliable high-speed data transmission inside every electronics system.Signal integrity is one of the most important factors to be considered when designing these packages (chip carriers and PCBs) and integrating these packages together.3、SI Analysis3.1. SI Analysis in the Design FlowSignal integrity is not a new phenomenon and it did not always matter in the early days of the digital era. But with the explosion of the information technology and the arrival of Internet age, people need to be connected all the time through various high-speed digital communication/computing systems. In this enormous market, signal integrity analysis will play a more and more critical role to guarantee the reliable system operation of these electronics products. Without pre-layout SI guidelines, prototypes may never leave the bench; without post-layout SI verifications, products may fail in the field. Figure 14-5 shows the role of SI analysis in the high-speed design process. From this chart, we will notice that SI analysis is applied throughout the design flow and tightly integrated into each design stage. It is also very common to categorize SI analysis into two main stages: reroute analysis and post route analysis.In the reroute stage, SI analysis can be used to select technology for I/Os, clock distributions, chip package types, component types, board stickups, pin assignments, net topologies, and termination strategies. With various design parameters considered, batch SI simulations on different corner cases will progressively formulate a set of optimized guidelines for physical designs of later stage. SI analysis at this stage is also called constraint driven SI design because the guidelines developed will be used as constraints for component placement and routing. The objective of constraint driven SI design at the reroute stage is to ensure that the signal integrity of the physical layout, which follows the placement/routing constraints for noise and timing budget, will not exceed the maximum allowable noise levels. Comprehensive and in-depth reroute SI analysis will cut down the redesign efforts and place/route iterations, and eventually reduce design cycle.With an initial physical layout, post route SI analysis verifies the correctness of the SI design guidelines and constraints. It checks SI violations in the current design, such as reflection noise, ringing, crosstalk and ground bounce. It may also uncover SI problems that are overlooked in the reroute stage, because post route analysis works with physical layout data rather than estimated data or models, therefore it should produce more accurate simulation results.When SI analysis is thoroughly implemented throughout the whole design process, a reliable high performance system can be achieved with fast turn-around.In the past, physical designs generated by layout engineers were merely mechanical drawings when very little or no signal integrity issues were concerned. While the trend of higher-speed electronics system design continues, system engineers, responsible for developing a hardware system, are getting involved in SI and most likely employ design guidelines and routing constraints from signal integrity perspectives. Often, they simply do not know the answers to some of the SI problems because most of their knowledge is from the engineers doing previous generations of products. To face this challenge, nowadays, a design team (see Figure 14-6) needs to have SI engineers who are specialized in working in this emerging technology field. When a new technology is under consideration, such as a new device family or a new fabrication process for chip packages or boards, SI engineers will carry out the electrical characterization of the technology from SI perspectives, and develop layout guideline by running SI modeling and simulation software [2]. These SI tools must be accurate enough to model individual interconnections such as visa, traces, and plane stickups. And they also must be very efficient so what-if analysis with alternative driver/load models and termination schemes can be easily performed. In the end, SI engineers will determine a set of design rules and pass them to the design engineers and layout engineers. Then, the design engineers, who are responsible for the overall system design, need to ensure the design rules are successfully employed. They may run some SI simulations on a few critical nets once the board is initially placed and routed. And they may run post-layout verifications as well. The SI analysis they carry out involves many nets. Therefore, the simulation must be fast, though it may not require the kind of accuracy that SI engineers are looking for. Once the layout engineers get the placement and routing rules specified in SI terms, they need to generate an optimized physical design based on these constraints. And they will provide the report on any SI violations in a routed system using SI tools. If any violations are spotted, layout engineers will work closely with design engineers and SI engineers to solve these possible SI problems.3.2.Principles of SI AnalysisA digital system can be examined at three levels of abstraction: log ic, circuit theory, and electromagnetic (EM) fields. The logic level, which is the highest level of those three, is where SI problems can be easily identified. EM fields, located at the lowest level of abstraction, comprise the foundation that the other levels are built upon [3]. Most of the SI problems are EM problems in nature, such as the cases of reflection, crosstalk and ground bounce. Therefore, understanding the physical behavior of SI problems from EM perspective will be very helpful. For instance, in the following multi-layer packaging structure shown in Figure 14-7, a switching current in via a will generate EM waves propagating away from that via in the radial direction between metal planes. The fields developed between metal planes will cause voltage variations between planes (voltage is the integration of the E-field). When the waves reach other visa, they will induce currents in those visa. And the induced currents in that visa will in turn generate EM waves propagating between the planes. When the waves reach the edges of the package, part of them will radiate into the air and part of them will get reflected back. When the waves bounce back and forth inside the packaging structure and superimpose to each other, resonance will occur. Wave propagation, reflection, coupling and resonance are the typical EM phenomena happening inside a packaging structure during signal transients. Even though EM full wave analysis is much more accurate than the circuit analysis in the modeling of packaging structures, currently, common approaches of interconnect modeling are based on circuit theory, and SI analysis is carried out with circuit simulators. This is because field analysis usually requires much more complicated algorithms and much larger computing resources than circuit analysis, and circuit analysis provides good SI solutions at low frequency as an electrostatic approximation.Typical circuit simulators, such as different flavors of SPICE, employ nodal analysis and solve voltages and currents in lumped circuit elements like resistors, capacitors and inductors. In SI analysis, an interconnect sometimes will be modeled as a lumped circuit element. For instance, a piece of trace on the printed circuit board can be simply modeled as a resistor for its finite conductivity. With this lumped circuit model, the voltages along both ends of the trace are assumed to change instantaneously and the travel time for the signal to propagate between the two ends is neglected. However, if the signal propagation time along the trace has to be considered, a distributed circuit model, such as a cascaded R-L-C network, will be adopted to model the trace. To determine whether the distributed circuit model is necessary, the rule of thumb is – if the signal rise time is comparable to the round-trip propagation time, you need to consider using the distributed circuit model.For example, a 3cm long stripling trace in a FR-4 material based printed circuit board will exhibits 200ps propagation delay. For a 33 MHz system, assuming the signal rise time to be 5ns, the trace delay may be safely ignored; however, with a system of 500 MHz and 300ps rise time, the 200ps propagation delay on the trace becomes important and a distributed circuit model has to be used to model the trace. Through this example, it is easy to see that in the high-speed design, with ever-decreasing signal rise time, distributed circuit model must be used in SI analysis.Here is another example. Considering a pair of solid power and ground planes in a printed circuit board with the dimension of 15cm by 15cm, it is very natural to think the planes acting as a large, perfect, lumped capacitor, from the circuit theory point of view. The capacitor model C= erA/d, an electro-static solution, assumes anywhere on the plane the voltages are the same and all the charges stored are available instantaneously anywhere along the plane. This is true at DC and low frequency. However, when the logics switch with a rise time of 300ps, drawing a large amount of transient currents from the power/ground planes, they perceive the power/ground structure as a two-dimensional distributed network with significant delays. Only some portion of the plane charges located within a small radius of the switching logics will be able to supply the demand. And voltages between the power/ground planes will have variations at different locations. In this case, an ideal lumped capacitor model is obviously not going to account for the propagation effects. Two-dimensional distributed R-L-C circuit networks must be used to model the power/ground pair.In summary, as the current high-speed design trend continues, fast rise time reveals the distributed nature of package interconnects. Distributed circuit models need to be adopted to simulate the propagation delay in SI analysis. However, at higher frequencies, even the distributed circuit modeling techniques are not good enough, full wave electromagnetic field analysis based on solving Maxwell’s equations must come to play. As presen ted in later discussions, a trace will not be modeled as a lumped resistor, or a R-L-C ladder; it will be analyzed based upon transmission line theory; and a power/ground plane pair will be treated as a parallel-plate wave guide using radial transmission line theory.Transmission line theory is one of the most useful concepts in today’s SI analysis. And it is a basic topic in many introductory EM textbooks. For more information on the selective reading materials, please refer to the Resource Center in Chapter 16.In the above discussion, it can be noticed that signal rise time is a very important quantity in SI issues. So a little more expanded discussion on rise time will be given in the next section.信号完整性介绍在高速数字设计领域，信号完整性已经成为一个严重的问题，是造成越来越多的挑战的设计工程师。
蓝牙中英文翻译
BluetoothIntroductionBluetooth is a forever, limited radio connect that resides o n a microchip. It was originally expanded through Swedish mo bile phone creator Ericsson in 1994 as a method to let lap top computers make calls above a mobile phone. As then, num erous organizations have signed on to create Bluetooth the low-power thoughtless wireless average for a broad variety ofdevices (LeVitus, 216-220). Industry spectators anticipate Bluetooth to be fitted in billions of devices through 2005. DiscussionDeveloped by engineers at Ericsson in the late 1990s, Blue tooth is more and more special technology that facilitates t houghtless wireless communication among a diversity of electro nic devices. Its mainly important aspect is that it permits devices to “talk”(relocate and orchestrate data) wirelessly with each other, terminating the requirement for the outwar dly continuous tangle of cables, cords, and adapters importan t for numerous today’s expertise.The Bluetooth Special Interest Group (SIG) was formed in 1 998 to manage the expansion and prologue of Bluetooth knowle dge (LeVitus, 216-220). IBM, Intel, Toshiba and Nokia connected with Ericsson as the beginning associates of the SIG, and in exc ess of 8,000 organizations have contracted since. So as to trade products with the Bluetooth requirement and logo, manufacturers should be associates of the SIG and the devices should meet well-outlined credentials. These procedures makesure that Bluetooth wireless devices international may converse with each other, apart from company or nation ofderivation.Speed and RangeRange is application specific and although a minimum rangeis mandated by the Core Specification, there is not a limit and manufacturers can tune their implementation to support the use case they are enabling.Range may vary depending on class of radio used in an impl ementation:·Class 3 radios-have a range of up to 1 meter or 3 feet ·Class 2 radios-most commonly found in mobile devices, have arange of 10 meters or 33 feet.·Class 1 radios-used primarily in industrial use cases，have a range of 100 meters or 300 feet.That creates Bluetooth technology appropriate for transporting lesser files for example cell phone contracts and text documents, also as lower-quality pictures and audio (Kumkum, 160-162).At these relocate speeds; Bluetooth may not actually deal st reaming video or high-quality pictures and audio at this end, except this possibly will alter in the future when fresh Bl uetooth standards are initiated.Simple and Competent to UtilizeCreating and configuring Bluetooth allowed devices is modera tely uncomplicated, with little extra commotion than acquire the two devices close to one another and twist them on.There is no requirement to mount drivers or further software to complex an ad-hoc, personal wireless network (Kumkum, 160-162). It has a uniform organization, meaning that some two wireless products attributing Bluetooth technology,despite of productor nation of origin, have the ability to converse faultlessly with each other.Common ApplicationsOne of the mainly ordinary applications of Bluetooth is hand s -free cell phone procedure. About each cell phone fashioned in our day has constructed Bluetooth (Meier, 15-20). Only pair phone with a Bluetooth headset, and he may talk whereas his phone is in his purse or pocket. Several of today’s car stereo s as well have fitted Bluetooth for hands-free calling in his vehicle. And if his vehicle has a plant stereo or grown-up aftermarket one that he merely doesn’t wish to restore, he may yet like hands-free identifying with a Bluetooth car kit. Bluetooth 3.0Bluetooth 3.0 is the fresh Bluetooth wireless typical adopted through the Bluetooth SIG on April 21, 2009. The fresh st andard supports elevated data remove speeds and constructs ah ead the preceding standards (Meier, 15-20). With its superior speed, the technology has the probable to transfigure the co nsumer electronics industry.PROTOCOLThe Bluetooth technology standard is set to make different a pplications can “communicate”with each other. Remote device s in communication use the same protocol stacks, while diffe rent applications need different protocol stacks. But, every application needs the data link layer and physical layer of the Bluetooth technology.The whole Bluetooth protocol stacksis shown as blow. Not any application should use all of the protocols, but one or some lists of these. The chart b elow shows the relationship between protocols, but the relati onship may change in some applications.The completely protocol stacks include Bluetooth special proto cols (like LMP and L2CAP) and not special ones (such as OB EX and UDP). The basic principle for designing protocol and protocol stacks is that use existing highlevel protocol as p ossible, ensure the combination of protocols and Bluetooth te chnology, and take the best advantage of the software and h ardware which adapt to the Bluetooth technology standards. Th e open Bluetooth technology makes device manufacturers can ch oose protocols freely as they like or used to.The protocols in Bluetooth protocol system.There are four layers in Bluetooth protocol system accordingto the SIG:·Core protocols·Cable replacement protocols·Telephony control protocols·Adopted protocolsExcept the protocol layers above, the standard also defines Host/Controller Interface (HCI),which provides command interface for baseband controller, connection manager, hardware state and control register.Bluetooth core protocols consist of the special protocols mad e by SIG. Most Bluetooth devices need core protocols, while other protocols are used depend on needs of the application. After all, cable replacement protocols, technology control p rotocols and adopted protocols based on the core protocols c onstitute the object-oriented protocols.·Core protocols·LMP (Link Management Protocol)Used for control of the radio link between two devices. Implemented onthe controllers.It identifies and encrypts through launching, exchanging and checking the connection, and decides the size of baseband da ta packets through conference. It also controls the power mo de and work cycle of wireless equipment, and connection stat us of unit equipment in piconet.·L2CAP (Logical Link Control & Adaptation Protocol)This protocol is used to multiplex multiple logical connectio ns between two devices using different higher level protocols, and provides segmentation and reassembly of on-air packets.In Basic mode, L2CAP provides packets with a payload configu rable up to 64kB, with 672 bytes as the default MTU, and 48 bytes as the minimum mandatory supported MTU.In Retransmission & Flow Control modes, L2CAP can be configu red for reliable or isochronous data per channel by performi ng retransmissions and CRC checks.Bluetooth Core Specification Addendum 1 adds two additional L 2CAP modes to the core specification. These modes effectively deprecate original Retransmission and Flow Control modes:·Enhanced Retransmission Mode (ERTM): This mode is an improv ed version of the original retransmission mode. This mode pr ovides a reliable L2CAP channel.·Streaming Mode (SM): This is a very simple mode, with no retransmissionor flow control. This mode provides an unreliabl e L2CAP channel.Reliability in any of these modes is optionally and/or addit ionally guaranteed by the lower layer Bluetooth BDR/EDR air interface by configuring the number of retransmissions and fl ush timeout (time after which the radio will flush packets).In-order sequencing is guaranteed by the lower layer.Only L2CAP channels configured in ERTM or SM may be operated over AMP logical links.·SDP (Service Discovery Protocol)Service Discovery Protocol (SDP) allows a device to discover services supported by other devices, and their associated par ameters. For example, when connecting a mobile phone to a B luetooth headset, SDP will be used for determining which Blu etooth profiles are supported by the headset (Headset Profile, Hands Free Profile, Advanced Audio Distribution Profile (A2DP) etc.) and the protocol multiplexer settings needed to connect to each of them. Each service is identified by a Universally Unique Identifier (UUID), with official services (Bluetooth profiles) assigned a short form UUID (16 bits rather than t he full 128)/vichitra·Cable replacement protocols(RFCOMM)Radio frequency communications (RFCOMM) is a cable replacement protocol used to create a virtual serial data stream. RFCOMM provides for binary data transport and emulates EIA-232 (formerly RS-232) control signals over the Bluetooth baseband layer.RFCOMM provides a simple reliable data stream to the user, similar to TCP. It is used directly by many telephony relat ed profiles as a carrier for AT commands, as well as being a transport layer for OBEX over Bluetooth.·Telephony control protocols (TCP).Telephony control protocol-binary (TCS BIN) is the bit-oriented protocol that defines the call control signaling for the establishment of voice and data calls between Bluetoothdevices. Additionally, “TCS BIN defines mobility management p rocedures for handling groups of Bluetooth TCS devices.”TCS-BIN is only used by the cordless telephony profile, which failed to attract implementers. As such it is only of historical interest.Adopted protocolsAdopted protocols are defined by other standards-making organizations and incorporated into Bluetooth’s protocol stack, allowing Bluetooth to create protocols only when necessary. T he adopted protocols include:·Point-to-Point Protocol (PPP): Internet standard protocol for transporting IP datagrams over a point-to-point link.·TCP/IP/UDP: For communicating with the device connected to Internet.·Object Exchange Protocol (OBEX): Session-layer protocol for the exchange of objects, providing a model for object and operation representation. It uses the client-server mode.· Wireless Application Environment/Wireless Application Protocol (WAE/WAP):WAE specifies an application framework for wireless devices and WAP is an open standard to provide mobile users access to telephony and information services.TechnologySPECTRUM AND INTERFERENCEBluetooth technology operates in the unlicensed industrial, sc ientific and medical (ISM) band at 2.4 to 2.485 GHz, usinga spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops/sec. The 2.4 GHz ISM band is ava ilable and unlicensed in most countries.SIM frequency band is open to all radio system, So the useof a certain frequency band will meet unpredictable interfe rence sources. Therefore, Bluetooth designs special fast ackno wledge and frequency hopping technique to ensure the stabilit y of link. Frequency hopping technique to divide the band i nto many frequency hopping channels, in a connection, radio transceiver “jump”from a channel to another constantly acc ording to certain code sequence. Only sender and receiver co mmunicate according to this law, and the rest of interferenc e may not press the same rule. The instantaneous bandwidth of Frequency hopping is very narrow, but through the spread spectrum technology it can make the narrow bandwidth one h undred times expanded into wideband, making the influence of interference may become very small. Comparing to other syst ems that work in the same frequency band, frequency hopping of Bluetooth works faster, data packet of Bluetooth is sho rter, which make it more stable than the other.ERROR CORRECTIONBluetooth supports circuit switching and packet switching two techniques, and defines two types of link connection, namel y connection-oriented synchronous link (SCO) and connectionless-oriented asynchronous link (ACL).Bluetooth use three error correction models:1/3 Forward Error Correction (FEC), 2/3forward Forward Error Correction and Au tomatic Repeat Request (ARQ). Purpose to the error correction is to reduce the possibility of retransmission, while at t he same time increase the extra expenses, but in a reasonab le errorless environment, redundant bids will reduce output. So the packet definition itself also keeps flexible ways. He nce the software can be defined whether to adopt FEC. In general, when the channel noise is large, Bluetooth system will uses FEC, in order to ensure the quality of communication: as to SCO link, 1/3 FEC is used; 2/3 FEC is used in ACL link. In Unnumbered ARQ, the data send in a time slot must receive a confirmation of receipt in the next time slot. On ly when the data is checked to be without mistake after he ader error detection and CRC at receiver will the confirmati on sent to sender, or an error message will be sent back. RANGERange is application specific and although a minimum range i s mandated by the Core Specification, there is not a limit and manufacturers can tune their implementation to support the use case they are enabling.Range may vary depending on class of radio used in an impl ementation:Class 3 radios-have a range of up to 1 meter or 3 feet. Class 2 radios-most commonly found in mobile devices , have a range of 10 meters or 33 feet.Class 1 radios-used primarily in industrial use cases , have a range of 100 meters or 300 feet.POWERIn order to make a Bluetooth equipment can also be in conn ection even in a very low power state, Bluetooth stipulates three energy saving state: Park state, Hold state and Snif f state. The energy saving efficiency of these states declin es one by one.The most commonly used radio is Class 2 and users 2.5mW of power. Bluetooth technology is designed to have very low p ower consumption. This is reinforced in the specification byallowing radios to be powered down when inactive.The Generic Alternate MAC/PHY in Version 3.0 HS enables the discovery of remote AMPs for high speed devices and tums on the radio only when needed for data transfer giving a p ower optimization benefit as well as aiding in the security of the radios.Bluetooth low energy technology, optimized for devices requiri ng maximum battery life instead of a high data transfer rat e, consumers between 1/2 and 1/100 the power of classic Blu etooth technology.SECURITYMobility and open of Bluetooth system makes safety problems extremely important. Although the frequency modulation techniqu e used by Bluetooth system has already provided a certain s ecurity, but Bluetooth system still need safety management to link layer and application layer. In link layer, Bluetooth system provides authentication, encryption and key management, and other functions. Each user has a Personal Identificatio n Number (PIN), which will be translated into 128 bit link key for one-way or both-way certification. Once the authentication finished, link will use encryphon key to encrypt. The link layer security mechanism provides a great deal of certification schemes and a flexible encryption scheme (means allow the consultation of the length of password). This me chanism is very important when the equipments in communicatio n are from different countries, because some countries will specify maximum password length. Bluetooth system will select the smallest maximum allowable password length of all equip ments in the piconet.Bluetooth system also supports the high level of protocol st ack in different applications of special security mechanisms. Bluetooth security mechanism builds trust relationship betwee n devices relying on pins. Once this relationship established , these pins can be stored in the equipment, in order to connection more quickly the next time.Source: Baidu Library蓝牙介绍蓝牙是一种永久、有限的无线连接，驻留在微芯片上。
计算机领域会议
计算机领域会议CORE Computer Science Conference Rankings Acronym Standard Name RankAAAI National Conference of the American Association for Artificial Intelligence A+AAMAS International Conference on Autonomous Agents and Multiagent Systems A+ ACL Association of Computational Linguistics A+ ACMMM ACM Multimedia Conference A+ ASPLOS Architectural Support for Programming Languages and Operating Systems A+ CAV Computer Aided Verification A+ CCS ACM Conference on Computer and Communications Security A+ CHI International Conference on Human Factors in Computing Systems A+ COLT Annual Conference on Computational Learning Theory A+ CRYPTO Advances in Cryptology A+ CSCL Computer Supported Collaborative Learning A+ DCC IEEE Data Compression Conference A+ DSN International Conference on Dependable Systems A+ EuroCrypt International Conference on the Theory and Application of Cryptographic Techniques A+ FOCS IEEE Symposium on Foundations of Computer Science A+ FOGA Foundations of Genetic Algorithms A+ HPCA IEEE Symposium on High Performance Computer Architecture A+ I3DG ACM-SIGRAPH Interactive 3D Graphics A+ ICAPS International Conference on Automated Planning and Scheduling A+ ICCV IEEE International Conference on Computer Vision A+ ICDE IEEE International Conference on Data Engineering A+ ICDM IEEE International Conference on Data Mining A+ ICFP International Conference on Functional Programming A+ ICIS International Conference on Information Systems A+ ICML International Conference on Machine Learning A+ ICSE International Conference on Software Engineering A+ IJCAI International Joint Conference on Artificial Intelligence A+ IJCAR International Joint Conference on Automated Reasoning A+ INFOCOM Joint Conference of the IEEE Computer and Communications Societies A+ InfoVis IEEE Information Visualization Conference A+ IPSN Information Processing in Sensor Networks A+ ISCA ACM International Symposium on Computer Architecture A+ ISMAR IEEE and ACM International Symposium on Mixed and Augmented Reality A+ ISSAC International. Symposium on Symbolic and Algebraic Computation A+ ISWC IEEE International Symposium on Wearable Computing A+ IWQoS IFIP International Workshop on QoS A+ JCDL ACM Conference on Digital Libraries A+ KR International Conference on Principles of KR & Reasoning A+ LICS IEEE Symposium on Logic in Computer Science A+ MOBICOM ACM International Conferencem on Mobile Computing and Networking A+ NIPS Advances in Neural Information Processing Systems A+ OOPSLA ACM Conference on Object Oriented Programming Systems Languages and Applications A+ OSDI Usenix Symposium on Operating Systems Design and Implementation A+ PERCOM IEEE International Conference on Pervasive Computing and Communications A+PERVASIVE International Conference on Pervasive Computing A+ PLDI ACM-SIGPLAN Conference on Programming Language Design & Implementation A+ PODC ACM Symposium on Principles of Distributed Computing A+ PODS ACM SIGMOD-SIGACT-SIGART Conferenceon Principles of Database Systems A+ POPL ACM-SIGACT Symposium on Principles of Prog Langs A+RSS Robotics: Systems and Science A+ RTSS Real Time Systems Symp A+ SENSYS ACM Conference on Embedded Networked Sensor Systems A+SIGCOMM ACM Conference on Applications, Technologies,Architectures, and Protocols for Computer CommunicationA+SIGGRAPH ACM SIG International Conference on Computer Graphics and Interactive Techniques A+ SIGIR ACM International Conference on Research and Development in Information Retrieval A+ SIGKDD ACM International Conference on Knowledge Discovery and Data Mining A+ SIGMETRICS ACM SIG on computer and communications metrics and performance A+ SIGMOD ACM Special Interest Group on Management of Data Conference A+ SODA ACM/SIAM Symposium on Discrete Algorithms A+ SOSP ACM SIGOPS Symposium on Operating Systems Principles A+ STOC ACM Symposium on Theory of Computing A+ UAI Conference in Uncertainty in Artifical Intelligence A+ UbiComp Uniquitous Computing A+ VLDB International Conference on Very Large Databases A+ WWW International World Wide Web Conference A+ ACM-HT ACM Hypertext Conf A AH International Conference on Adaptive Hypermedia and Adaptive Web-Based Systems A AID International Conference on AI in Design A AIED International Conference on Artificial Intelligence in Education A AIIM Artificial Intelligence in Medicine A AIME Artificial Intelligence in Medicine in Europe A AiML Advances in Modal Logic A ALENEX Workshop on Algorithm Engineering and Experiments A ALIFE International Conference on the Simulation and Synthesis of Living Systems A AMAI Artificial Intelligence and Maths A AMIA American Medical Informatics Annual Fall Symposium A AOSD Aspect-Oriented Software Development A APPROX International Workshop on Approximation Algorithms for Combinatorial Optimization Problems A ASAP International Conference on Apps for Specific Array Processors A ASE Automated Software Engineering Conference A ASIACRYPT International Conference on the Theory and Applications of Cryptology A ASIS&T Annual conference of American Society for Information Science and Technology A ATVA International Symposium on Automated Technology for Verification and Analysis A AVSS Advanced Video and Signal Based Surveillance A BMVC British Machine Vision Conference A BPM International Conference in Business Process Management A CADE International Conference on Automated Deduction A CAIP International Conference on Computer Analysis of Images and Patterns A CaiSE International Conference on Advanced Information Systems Engineering A CANIM Computer Animation A CASES International Conference on Compilers, Architecture, and Synthesis for Embedded Systems A CBSE International Symposium Component-Based Software Engineering A CC International Conference on Compiler Construction A CCC IEEE Symposium on Computational Complexity A CCGRID IEEE Symposium on Cluster Computing and the Grid ACDC IEEE Conference on Decision and Control A CGI Computer Graphics International ACGO Code Generation and Optimization A CIDR Conference on Innovative Data Systems Research A CIKM ACM International Conference on Information and Knowledge Management A CLUSTER Cluster Computing Conference A COCOON International Conference on Computing and Combinatorics A CogSci Annual Conference of the Cognitive Science Society A COLING International Conference on Computational Liguistics A CONCUR International Conference on Concurrency Theory A CoNLL Conference on Natural Language Learning ACoNLL Conference on Natural Language Learning A CoopIS International Conference on Cooperative Information Systems A Coordination International Conference on Coordination Models and Lanuguages A CP International Conference on Principles & Practice of Constraint Programming ACPAIOR International Conference on Integration of Artificial Intelligence and Operations Research Techniques in Constraint Programming for Combinatorial Optimization ProblemsACSB IEEE Computational Systems Bioinformatics Conference A CSCW ACM Conference on Computer Supported Cooperative Work A CSFW IEEE Computer Security Foundations Workshop A CSSAC Cognitive Science Society Annual Conference A CVPR IEEE Conference on Computer Vision and Pattern Recognition A DAC Design Automation Conf A DAS International Workshop on Document Analysis Systems A DASFAA Database Systems for Advanced Applications A DATE IEEE/ACM Design, Automation & Test in Europe Conference A DEXA International Conference on Database and Expert Systems Applications A DIGRA Digital Games Research Conference A DIS Designing Interactive Systems A DISC International Symposium on Distributed Computing (ex WDAG)A DocEng ACM Symposium on Document Engineering A DOOD Deductive and Object-Oriented Databases A DUX Design for User Experience A EAAI Engineering Applications of Artifical Intelligence A EACL European Association of Computational Linguistics A EASE International Conference on Evaluation and Assessment in Software Engineering A EC ACM Conference on Electronic Commerce A ECAI European Conference on Artificial Intelligence A ECCV European Conference on Computer Vision A ECDL European Conference on Digital Libraries A ECIS European Conference on Information Systems A ECML European Conference on Machine Learning A ECOOP European Conference on object-oriented programming A ECRTS Euromicro Conference on Real-Time Systems A ECSCW European Conference on Computer Supported Cooperative Work A ECWeb International Conference on Electronic Commerce and Web Technology A EDBT Extending Database Technology A EKAW International Conference on Knowledge Engineering and Knowledge Management A EMMSAD Exploring Modelling Methods in Systems Analysis and Design A EMNLP Empirical Methods in Natural Language Processing A EMSOFT ACM Conference on Embedded Software A ESA European Symposium on Algorithms A e-science IEEE International Conference on e-science and Grid Computing AESEM Internation Symposium on Empirical Software Engineering and Measurement A ESOP European Symposium on Programming AESORICS European Symposium on Research in Computer Security A ESQARU International Joint Conference on Qualitative and Quantitative Practical Reasoning A ESWC European Semantic Web Conference A EuroCOLT European Conference on Computational Learning Theory A EUROGRAPH European Graphics Conference A EuroPar International Conference on Parallel Processing A EuroPVM/MPI Euopean PVM/MPI Uswers' Group Conference A EuroSpeech European Conference on Speech Communication and Technology A EuroSPI European SPI A EuroSys Eurosys Conference A EWSN European conference on Wireless Sensor Networks A FCCM IEEE Symposium on Field Programmable Custom Computing Machines A FLOPS International Symposium on Functional and Logic Programming AFME Formal Methods Europe A FODO International Conference on Foundation on Data Organization AFORTE IFIP Joint Int'l Conference on Formal Description Techniques and Protocol Specification, Testing, And VerificationAFPSAC Formal Power Series and Algebraic Combinatorics AFSE ACM Conference on the Foundations of Software Engineering (inc ESEC-FSE when held joInternationaly [sic])AFSR International Conference on Field and Service Robotics A FST&TCS Foundations of Software Technology & Theoretical Computer Science A FUZZ-IEEE IEEE International Conference on Fuzzy Systems A GD Graph Drawing A Grid International Conference on Grid Computing A Group ACM Special Interest Group on Supporting Group Work (was SIGGRoup)A HiPC International Conference on High Performance Computing A HOTCHIPS (HCS)Symposium on High Performance Chips A HOTNETS ACM Workshop on Hot Topics in Networks A HotOS USENIX Workshop on Hot Topics in Operating Systems A HPDC IEEE International Symposium on High Performance Distributed Computing A Hypertext ACM Conference on Hypertext and Hypermedia A IC3N International Conference on Computer Communication and Networks A ICADL International Conference of Asian Digital Libraries A ICALP International Colloquium on Automata, Languages and Programming A ICALT IEEE International Conference on Advanced Learning Technologies A ICARCV International Conference on Control, Automation, Robotics and Vision A ICC IEEE International Conference on Communications A ICCAD International Conference on Computer-Aided Design A ICCL IEEE International Conference on Computer Languages A ICCS International Conference on Computational Science A ICCS International Conference on Conceptual Structures A ICDAR IEEE International Conference on Document Analysis and Recognition A ICDCS IEEE International Conference on Distributed Computing Systems A ICDT International Conference on Database Theory A ICECCS IEEE International Conference on Engineering and Complex Computer Systems A ICER International Computing Education Research Workshop A ICGG International Conference on Grid Computing A ICIAP International Conference on Image Analysis and Processing A ICIP IEEE International Conference on Image Processing AICLP International conference on Logic Programming A ICMAS International Conference on Multi Agent Systems AICNN IEEE International Conference on Neural Networks A ICNP International Conference on Network Protocols A ICONIP International Conference on Neural Information Processing A ICPP International Conference on Parallel Processing A ICPR International Conference on Pattern Recognition A ICS ACM International Conference on Supercomputing A ICSC2International Computer Symposium Conference A ICSM International. Conferenceon Software Maintenance A ICSOC International Conference on Service Oriented Computing A ICSP International Conference on Software Process A ICSPC International Conference on Security in Pervasive Computing A ICSR IEEE International Conference on Software Reuse A ICTL International Coference on Temporal Logic A IDA Intelligent Data Analysis A IEEE-Alife IEEE International Symposium on Artificial Life A IEEE-CEC Congress on Evolutionary Computation A IEEE-MM IEEE International Conference on Multimedia Computing and Systems A IEEETKDE IEEE Transactions on Knowledge and Data Engineering A IFIP_WG 11.3IFIP WG 11.3 Working Conference on Data and Applications Security (was IFIP-DBSEC)AIFIP_WG 11.3IFIP WG 11.3 Working Conference on Data and Applications Security (was IFIP-DBSEC)A IJCNLP International Joint Conference on Natural Language Processing A IJCNN IEEE International Joint Conference on Neural Networks A ILPS International Logic Programming Symposium A IM IFIP/IEEE Integrated Management (odd years sharing with NOMS)A IMC Internet Measurement Conference A INTERACT IFIP International Conference on Human-Computer Interaction A IPCO MPS Conference on integer programming & combinatorial optimization A IPDPS IEEE International Parallel and Distributed Processing Symposium (was IPPS and SPDP)A ISAAC International Symposium on Algorithms and Computation A ISD International Conference on Information Systems Development A ISESE International Symposium on Empirical Software Engineering A ISMB Intelligent Systems in Molecular Biology A ISR International Symposium on Robotics A ISSCC IEEE International Solid-State Circuits Conference A ISSR International Symposium on Robotics Research A ISSRE International Symposium on Software Reliability Engineering A ISSTA Internation Symposium on Software Testing and Analysis A ISTA International Conference on Information Systems Technology and its Application A ISTCS Israel Symposium on Theory of Computing and Systems A ISWC International Semantic Web Conference A ITiCSE Annual Conference on Integrating Technology into Computer Science Education A ITS International Conference on Intelligent Tutoring Systems A IUI Intelligent User Interfaces A IVCNZ Image and Vision Computing Conference A JELIA Logics in Artificial Intelligence, European Conference A JICSLP/ICLP/ILPS International Conference/Symposium on Logic Programming (Joint)A K-CAP Knowledge capture A LCN IEEE Conference on Local Computer Networks A LCTES ACM SIGPLAN Conference on Languages, Tools, and Compilers for Embedded Systems A LPAR Logic Programming and Automated Reasoning A LPNMR International Conference on Logic Programming and Non-monotonic Reasoning A MASCOTS Symposium Model Analysis & Simulation of Computer & Telecommunications Systems A MASS IEEE International Conference on Mobile Ad-hoc and Sensor Systems A MassPar Symposium on Frontiers of Massively Parallel Processing AMICRO International Symposium on Microarchitecture A Middleware ACM/IFIP/USENIX th International Middleware Conference A MIR ACM SIGMM International Woekshop on Multimedia Information Retrieval A MMCN ACM/SPIE Multimedia Computing and Networking A MMSP International Workshop on Multimedia Signal Processing A MOBIHOC ACM Symposium of mobile and ad hoc computing A MobileHCI International Conference on Human-Computer Interaction with Mobile Devices and Services A Mobiquitous International Conference on Mobile and Ubiquitous Systems: Networks and Services A Mobisys ACM SIGMOBILE International Conference on mobile systems, applications and services A MODELS International Conference on the Unified Modeling Language (formerly UML)AMSWIM ACM/IEEE International Conference on Modelling, Analysis and Simulation of Wireless and Mobile SystemsANAACL North American Association for Computational Linguistics A NDSS Usenix Networked and Distributed System Security Symposium A Net Object Days Includings [sic] MATES, ENASE etc.A NetStore Network Storage Symposium A Networking 200X IFIP Networking 200X A NOSSDAV Network and OS Support for Digital A/V A NSDI Symposium on Networked Systems, Design and Implementation A OPENARCH IEEE Conference on Open Architecture and Network Programming A P2P IEEE International Conference on Peer-toPeer Computing A PACT International Conference on Parallel Architecture and Compilation Techniques APADL Practical Aspects of Declarative Languages A PADS ACM/IEEE/SCS Workshop on Parallel & Distributed Simulation A PAKDD Pacific-Asia Conference on Knowledge Discovery and Data Mining A PDC Participatory Design Conference A PEPM ACM SIGPLAN Workshop on Partial Evalutation and Program Manipulation A PERFORMANCE IFIP International Symposium on Computing Performance, Modelling, Measurement and Evaluation A PG Pacific Graphics A PKDD European Conference on Principles and Practice of Knowledge Discovery in Databases A PPoPP Principles and Practice of Parallel Programming A PPSN Parallel Problem Solving from Nature A PRO-VE IFIP Working Conferences on Virtual Enterprises A PT Performance Tools - International Conference on Model Techniques & Tools for CPE A QoSA Conference on the Quality of Software Architectures A QSIC International Quality Software Conference A RAID Symposium on Recent Advances in Intrusion Detection A RANDOM International Workshop on Randomization and Computation A RE IEEE Requirements Engineering A RECOMB Annual International Conferenceon Comp Molecular Biology A RoboCup Robot Soccer World Cup A RST International Conference on Reliable Software Technologies A RTA International Conference on Rewriting Techniques and Applications A RTAS IEEE Real-Time and Embedded Technology and Applications Symposium A S&P IEEE Symposium on Security and Privacy A SARA Symposium on Abstraction, Reformulation and Approximation A SAS Static Analysis Symposium A SAT International Conference on Theory and Applications of Satisfiability Testing A SCA ACM SIGGRAPH/Eurographics Symposium on Computer Animation ASCC IEEE International Conference on Services Computing A SCG ACM Symposium on Computational Geometry ASCOPES International Workshop on Software and Compilers for Embedded Systems A SDM SIAM International Conference on Data Mining A SDSDI Unix Symposium on Operating Systems Design and Implementation A SIGCSE ACM Special Interest Group on Computer Science Education Conference A SMS IEEE International Symposium on Software Metrics A SPAA Symposium on Parallelism in Algorithms and Architectures A SPICE Software Process Improvement and Capability Determination A SRDS Symposium on Reliable Distributed Systems A SSDBM International Conference on Scientific and Statistical Data Base Management A SSPR Structural and Statistical pattern recognition A SSR ACM Symposium on Software Reusability A SSTD International Symposium on Spatial Databases A STACS Symposium on Theoretical Aspects of Computer Science A SUPER ACM/IEEE Supercomputing Conference A SWAT Scandinavian Workshop on Algorithm Theory A TABLEAUX International Conference on Theorem Proving with Analytic Tableaux and Related Methods A TACAS Tools and Algorithms for Construction and Analysis of Systems A TARK Theoretical Aspects of Rationality and Knowledge A TIME International Symposium on Temporal Representation and Reasoning A TREC Text Retrieval Conference A UIST ACM Symposium on User Interface Software and Technology A UM International Conference on User Modelling A USENIX USENIX Annual Technical Conference A USENIX-Security Usenix Security A USITS Unix Symposium on Internet Technologies A VCIP SPIE International Conference on Visual Communications and Image Processing A VIS IEEE Visualization A VL/HCC IEEE Symposium on Visual Languages and Human-Centric Computing (was VL)A VLSI IEEE Symposium VLSI Circuits AVLSI IEEE Symposium VLSI Circuits A VMCAI Verification, Model Checking and Abstract Interpretation A WACV IEEE Workshop on Apps of Computer Vision A WADS Workshop on Algorithms and Data Structures A WICSA EEE/IFIP Working Conference on Software Architecture A WISE International Conference on Web Information Systems Engineering A WoWMoM IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks A WPHOL International Conference on Theorem Proving in Higher Order Logics A AAAAECC International Symposium on Applied Algebra, Algebraic Algorithms and Error-Correcting Codes B AAIM Conference on Algorithmic Aspects in Information and Management B ACAL Australian Conference on Artificial Life B ACCV Asian Conference on Computer Vision B ACE Australasian Conference on Computer Science Education B ACIS Australasian Conference on Information Systems B ACISP Australasian Conference on Information Security and Privacy B ACIVS Advanced Concepts for Intelligent Vision Systems B ACOSM Australian Conference on Software Metrics B ACRA Australian Conference on Robotics and Automation B ACS Australian Supercomputing Conf BACSAC Australasian Computer Systems Architecture Conference (now Asia-Pacific Computer Systems Architecture Conference)BACSC Australasian Computer Science Conference B ACSD Application of Concurrency to System Design B ADBIS Symposium on Advances in DB and Information Systems B ADC Australasian Database Conference B ADCS Australasian Document Computing Symposium BADHOC-NOW International Conference on AD-HOC Networks & Wireless B ADTI International Symposium on Advanced DB Technologies and Integration B AI*IA Congress of the Italian Assoc for AI B AINA International Conference on Advanced Information Networking and Applications (was ICOIN)B AISP Australasia Conference on Information Security and Privacy B ALEX Algorithms and Experiments B ALG ENGG Workshop on Algorithm Engineering B ALP International Conference on Algebraic and Logic Programming B ALTAW Australasian Language Techology Association Workshop B AMCIS Americas Conference on Information Systems B AMOC Asian International Mobile Computing Conferrence B ANALCO Workshop on Analytic Algorithms and Combinatorics B ANNIE Artificial Neural Networks in Engineering Conference B ANTS International Workshop on Ant Colony B ANZIIS Australian and New Zealand Intelligent Information Systems Conference B AofA Conference on Analysis of Algorithms B AOIR Internet Research B AOIS Agent-Oriented Information Systems Workshop B AOSE Agent-Oriented Software Engineering Workshop B APAMI Asia Pacific Association for Medical Informatics Conference B APBC Asia-Pacific Bioinformatics Conference B APCC IEEE Asia Pacific Conference on Communications B APCHI Asia-Pacific Conference on Computer Human Interaction B APLAS ASIAN Symposium on Programming Languages and Systems B APNOMS Asia-Pacific Network Operations and Management Symposium B APSEC Asia-Pacific Software Engineering Conference B APWEB Asia Pacific Web Conference B ARA National Conference of the Australian Robot Association B ARES International Conference on Availability, Reliability and Security B ASADM Chicago ASA Data Mining Conference- A Hard Look at DM B ASIAN Asian Computing Science Conference BASS IEEE Annual Simulation Symposium B ASWEC Australian Software Engineering Conference B ASWEC Australian Software Engineering Conference B AUIC Australasian User Interface Conference B AusAI Australian Joint Conference on Artificial Intelligence B AusDM Australian Data Mining Conference B AusWIT Australian Women in IT Conference B AWOCA Australasian Workshop on Combinatorial Algorithms B AWRE Australian Workshop on Requirements Engineering B AWTI Argentine Workshop on Theoretical Informatics B BASYS IEEE/IFIP International Conference on Information Technology for Balanced Automation Systems B BNCOD British National Conference on Databases B Broadnets International Conference on Broadband Communications, Networks and Systems B CAAI Canadian Artificial Intelligence Conference B CAAN Workshop on Combinatorial and Algorithmic Aspects of Networking B CACSD IEEE/IFAC Joint Symposium on Intelligent Control B CAIA Conference on Artificial Intelligence for Applications B CATS Computing: The Australasian Theory Symposium B CCA IEEE International Conference on Control Applications B CCCG Canadian Conferenceon Computational Geometry B CCW IEEE Computer Communications Workshop B CD IFIP/ACM Working Conference on Component Deployment B CEAS International Conference on Email and Anti-Spam BCEC/EEE IEEE Conference on Electronic Commerce Technology and Enterprise Computing, e_Commerce and e-ServicesBCGA Workshop on Computational Geometry and Applications B CHES Cryptographic Hardware and Embedded Systems B CIAA International Conference on Implementation and Application of Automata B CIAC Italian Conference on Algorithms and Complexity B CICLING Conference on Intelligent Text Processing and Computational Linguistics B CISTM Conference on Information Science, Technology and Management B CITB Complexity and information-theoretic approaches to biology B COCOA Conference on Combinatorial Optimization and Applications B COMAD International Conference on Management of Data B COMMONSENSE Symposium on Logical Formalizations of Commonsense Reasoning B CompLife International Symposium on Computational Life Science B COMPSAC International Computer Software and Applications Conference B CONPAR International Conference on Vector and Parallel Processing B CPM Combinatorial Pattern Matching B CSL, 2 th Annual Conference on Computer Science Logic B DAC Digital Arts and Culture B DAFX Digital Audio Effects Conference B DAIS IFIP International Conference on Distributed Applications and Inoperable Systems B DaWaK Data Warehousing and Knowledge Discovery B DB&IS International Baltic Conference on Databases and Information Systems B DCOSS IEEE Conference on Distributed Computing in Sensor Systems B DICTA Australian Pattern Recognition Society Conference B DISRA IEEE International Workshop on Distributed Intelligent Simululation and Real-Time Applications B DITW Internationale Tagung Wirtschaftsinformatik B DLT Developments in Language Theory B DMTCS International Conference on Discrete Mathematics and Theoretical Computer Science B DNA Meeting on DNA Based Computers B DSOM IFIP/IEEE International Workshop on Distributed Systems Operations and Management B DS-RT Distributed Simulation and Real-time Applications B DSS Distributed Simulation Symposium B DX Diagnostics B DYSPAN IEEE Dynamic Spectrum Access Networks B ECAIM European Conference on AI in Medicine BECAIM European Conference on AI in Medicine B ECAL European Conferene on Artificial Life BECBS Annual IEEE International Conference and Workshop on the Engineering of Computer Based SystemsBECCB European Conference on Computational Biology B ECEG Eurpopean Conference on e-Government B ECIME European Conference on Information Management and Evaluation B ECIR European Conference on Information Retrieval B ED-MEDIA World Conference on Educational Multimedia, Hypermedia and Telecommunications B EDOC The Enterprise Computing Conference B EEE IEEE e-technology, e-service and e-commerce conference B EGC European Grid Conference B Emnets IEEE Embedded Sensor Networks Worskhop BEPIA Portuguese Conference on Artificial Intelligence B ER International Conference on Conceptual Modeling BERCIM/CSCLPERCIM Annual Workshop on Constraint Solving and Contraint Logic Programming B ESEA Euromicro International Conference on software engineering and applications B ESEC European Software Engineering Conference B ESM European Simulation Multiconference B ESS European Simulation Symposium B EuAda Ada-Europe International Conference on Reliable Software Technologies B EUROGP European Conference on Genetic Programming B EuroPDP EUROMICRO Conference on Parallel, Distributed and Network-Based processing B EUSIPCO European Signal Processing Conference B EWLR European Workshop on Learning Robots B FASE Fundamental Approaches to Software Engineering B FCKAML French Conference on Knowledge Acquisition & Machine Learning B FCT Fundamentals of Computation Theory B FEM International Conference on Formal Engineering Methods B FEWFDB Far East Workshop on Future DB Systems B FIE Frontiers in Education B FINCRY Financial Cryptography B FOSSACS Foundations of Software Science and Computational Structures B FSENCRY Fast Software Encryption B FTP International Workshops on First-Order Theorem Proving B FTRTFT Formal Techniques in Real-Time and Fault Tolerant Systems B FUN Conference on fun with algorithms B GECCO Genetic and Evolutionary Computations B GLOBECOM IEEE Global Telecommunications Conference B GMP Geometry Modeling and Processing B GPCE International Conference on Generative Programming and Component Engineering B HASE IEEE International Symposiumon High Assurance Systems Engineering B HICSS Hawaii International Conference on System Sciences B HLT Human Language Technologies B HPCN International Conference on High Performance Computing and Networking B HPSR IEEE Workshop on High Performance Switching and Routing B IAAI Innovative Applications in AI B ICA3PP IEEE International Conference on Algorithms and Architectures for Parallel Processing B ICAIL International Conference on Artificial Intelligence and Law B ICANN International Conference on Artificial Neural Networks B ICASSP IEEE International Conference on Acoustics, Speech and Signal Processing B ICATPN International Conference on the Application and Theory of Petri Nets B ICCB International Conference on Case-Based Reasoning B ICCBSS IEEE International Conference on COTS-Based Software Systems B ICCE International Conference on Computers in Education B ICCI International Conference on Computing and Information B ICDCN IEEE International Conference on Distributed Computing and Networking B ICEBE IEEE Conference on e-Business Engineering B。
V-Moda Crossfade 3 Wireless XFBT3 无线蓝牙过头耳 нау耳头戴说明
OVER-EAR BLUETOOTH® HEADPHONESIf serial number on the product, the manual cover or bottom of packaging is missing or defaced, please return to retailer immediately.Before using this product, carefully read the safety and warranty information in the booklets provided. Please then keep the documents where they can be available for immediate reference. To acquire a full printable version of the manual, please visit /manuals* This document explains the specifications of the product at the time that the document was issued. For the latest information, refer to .* Use a standard USB AC adaptor (5V /over 500mA) for charging.* This product is equipped with a lithium-ion battery.* Even if you do not use this product for an extended period of time, you should charge it once every three months to prevent the internal lithiumion battery from degrading. * Ambient temperature range during charging: 5–35°C* However, in order to take full advantage of the rechargeable lithium-ion battery’s performance, we recommend that you charge it in a temperature range of 10–30°C. * Take care not to pinch your fingers when opening or closing the headphones.* Charge the device using the included USB cable. Do not use the included USB cable with any other device.Welcome to V-MODA, the music lifestyle. We sincerely hope you enjoy our headphones, the pinnacle of sound and quality design. With the essence of music at the foundation of all we do, we have precisely engineered our headphones to provide an enjoyable and natural sound signature, which invokes the sense of listening to your music live.1. Crossfade 3 Wireless Over-EarHeadphones2. Carrying Case3. 1-Button SpeakEasy Mic Cable4. USB-C Charging Cable5. 1/4" Pro Adapter Headphones Accessories BoomPro X Mic, custom metal shields, Audio Cables, 3-Button SpeakEasy Mic Cable and XL cushions are available at .12345Push hair back, extend the earcups from headband until they fit comfortably on ear, creating a snug fit to ensure highest sound quality and comfortVery important: Place earcups on corresponding ear. “L” on left ear, “R” on right ear 12When using the included cable, insert straight plug into earcup (not 45° angled plug)When wearing headphones wired (with cable connected), hang cable in front of your head to ensure headphones stay put during strenuous activity 3441235 761 2 3 4 5 6 7To turn headphones on, slide the 3-way switch to the middle position. LED will start to blink once per secondOnce powered on (3-way switch in middle position) the headphones automatically connect to last paired device in a few seconds. Be sure the Bluetooth on your device is on Once powered on, slide 3-way switch to the right, hold 3 seconds, when the LED starts to blink twice per second, release the switch. The switch will return to the middle position and begin to search. Once appears in the “new Bluetooth devices” section on your phone, select it to begin pairing 13245Connect the USB-C charging cable to charge headphonesTo prevent malfunction or equipment failure, turn the volume down and turn the headphone off before connecting to a power sourceE nsure the headphones are switched off, charged and within 1m of the device Activate Bluetooth in the settings of your new deviceOnce powered on, slide switch to the right, hold 3 seconds, when the LED starts to blink twice per second, release the switch and enter secondary pairing mode (sonar sound)W hen appears in the “new Bluetooth devices” section on your device, select it to pairBlinking orange LEDFading orange LEDWhite LEDNote: The headphones' memory can hold up to 8 devices. You will only need to re-pair a device if the headphones is reset or if you pair a ninth device. Pairing a ninth device will overwrite the first device paired.6E nsure that the first pairing and secondary pairing procedures have beencompletedTo switch between devices via multipoint, ensure that both of your paired devices have Bluetooth activatedTurn the headphones off and then on againS elect in the Bluetooth settings of the device you want to play audio fromPress “Play” to play audio from your selected deviceThe headphones will now switch its active connection to your selected device. You may only listen to audio from one device at a timePress once (music pauses automatically)Press and hold for 1-2 seconds then releasePress oncePress twicePress three timesPress and hold for 3 seconds**Depending on your devices, there may be restrictions on the use of the voice assistant.Press + buttonPress – buttonPress and hold "+" and "-" at the same time for 3 seconds. LED lighting will change to blinking white• Click V button once to pause and again to resume playback • Click V button twice quickly for next track • Click V button three times quickly for previous track• Click V button once to answer incoming call, click once to end call • Press and hold V button down for about two seconds to decline an incoming call 12Compatible with all Bluetooth smartphones, tablets, iPhone ®, iPad ®, iPod ®, Android™, computersand any gaming or audio device with a 3.5mm or 6.35mm (1/4”) port.Get the app from Google Play or the App Store and download/install the app to your devicePair the headphones with your device settingsGo to and follow the procedure *If you're using an already-paired mobile device:Go to and follow the procedureOpen and activate appIf you see on the screen, select it to connect. Tap "pairing" if the app screen asked you for pairing. When the update software is available, you will receive a notification to update the software.123• Fully charge the headphones and your device• Move the device closer to the headphones• Move away from any possible interference (wireless routers, other Bluetooth devices, microwaves etc.)• Close any application on your device that is not in use and disable Wi-FiAfter closing the app and disconnect Bluetooth, try the following procedures:D elete V-MODA Crossfade 3 from Bluetooth device list of your deviceClear headphones' device paired history by followingRetry the pairing by following the pairing procedureE ven after trying this procedure if you are not able to connect, reboot your device and try pairing procedure againHold the two ear cups lightly together, cushion to cushionPlace the heel of other hand on top of headbandPush gently together to activate the CliqFold hingePlace the headphones in the carrying case, with the headband placed closest to the case’s hingeInsert any cables you wish in the extra space belowZip the carrying case to close 123456If you are experiencing trouble with your headphones, please refer to the troubleshooting guidelines below. If the problem persists, please contact the V-MODA Support Team or the nearest Roland service center.• Make sure headphones are not connected to the charger andthey are powered on• Turn off the headphones and turn them on again• Remember to turn on the Bluetooth feature on your device• Turn off the Bluetooth feature on any other device which hasbeen previously paired• Reset paired devices history by pressing and holding Volume+ and Volume - for 3 seconds• Try to pair with another device to make sure that both theheadphones and your Bluetooth device are working properly• Go to Bluetooth settings and select “V-MODA Crossfade 3”• Check the battery• Check the pairing• Make sure the audio source is playing• Make sure the volume on the device is not muted or turned down• Reboot the source/device• Turn off the headphones and turn them on again• Reset paired devices history of the headphones• Try streaming from another device or select another track • Move the device and headphones closer (max 33 feet or 10m)• Keep away from any possible interference (wireless routers, other Bluetooth devices, microwaves etc.)• Close any applications on your device that are not in use and disable Wi-FiTry streaming from another device or select another track. Due to technology limitations, there may be a delay from some sources or applicationsMake sure the audio device and the headphones jacks are free of debris and that the cable is securely connectedTurn off any audio enhancement features on audio device. Make sure cable is firmly connected to the headphones (use straight plug) and device (use 45°plug). If the problem persists, try another cableMake sure cable is firmly connected to the headphone by ensuring male 3.5mm is inserted into female 3.5mm all the wayCheck to make sure the problem is not with the audio device or the file you are listening to. Ensure the EQ settings on the device are set properly. Make sure you have a snug fit and that the driver is pointing directly towards the ear• Make sure the charging cable and source are functioning properly• Make sure both USB plugs are firmly connected into their sockets• Disconnect and reconnect the USB charcing cable• If charging with your computer, make sure the USB port is powered and remember to plug in your computerA charging error occurredCould the ambient temperature be above 35°C (95°F)?• Charging might stop for a while in order to protect the rechargeable lithium-ion battery. Use the unit in the recommended ambient temperature range of 10–30°C(50–86 °F)• If the indicator continues blinking fast orange even though you are charging in the recommended temperature range, contact the V-MODA Support Team or your dealer or nearest Roland service centerCharge the headphones and then turn on©2022 V-MODA. All rights reserved.V, V-MODA and the V-MODA logo are registered trademarks of V-MODA.Patents: roland.cm/patentsThe Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc.and any use of such marks by V-MODA is under license.Qualcomm aptX is a product of Qualcomm Technologies, Inc. and/or its subsidiaries. Qualcomm is a trademark of Qualcomm Incorporated, registered in the United States and other countries. aptX is a trademark of Qualcomm Technologies International, Ltd., registered in the United States andother countries.Apple and the Apple logo are trademarks of Apple Inc., registered in the U.S. and other countries.Google Play and the Google Play logo are trademarks of Google LLC.Other trademarks and trade names are those of their respective owners.Roland Corporation U.S.5100 S. Eastern Ave, Los Angeles, CA90040-2938For any issues relating to your V-MODA product, please contact our Support Team directly./support******************+1 888.866.3252REGISTER NOW AT。
无线调频发射器的毕业设计论文(内有外文翻译资料)
无线调频发射器的设计The Design of Wireless Frequency Modulation Transmitter摘要利用无线通信信道的远距离语音传输业务，是近年来发展很快的一门技术。
由于语音业务对误码不敏感，可以采用调频方式发送信息。
调频发射器可以使音频信息传送到附近的任意FM接收机。
本设计中使用AT89S52控制调频发射的频率，选择了数码管显示发射的频率状态。
选择了ROHM BH1415F集成电路产生调频调制发射信号的频率。
芯片的主要特征:体积小，准确性高，而且容易产生发射频率。
这个系统的各个部分可以进行深入的独立设计研究，现在把它们组合成一个典型的调频发射系统。
本设计使用模拟调频技术，在88MHz--98MHz的频段上，实现了线路输入语音信号的小功率远距离单工发送。
系统发射功率大约20mW，发射距离大于20m，本系统可实现无明显失真的语音传输。
关键词：调频；语音传输；ROHM BH1415ABSTRACTThe remote audio service code through wireless communication channels is a fast developing technology in recent years. As the audio service code is not sensitive to the mistaken code, the frequency modulation can be used to send information.The FM Transmitter will allow almost any audio source to be transmitted to any nearby FM receiver. The A T89S52 to be used to control the transmission frequency.The LED was chosen, providing enough space for all output situations. The ROHM BH1415F integrated circuit was chosen to create the frequency modulated audio output signal. Chip features include: small size, accuracy, and easily programmed transmission frequency. These system components have been thoroughly researched separately and are now in the process of being integrated to produce a working prototype FM Transmitter. The simulating frequency modulation technique was adopted in the design .In the frequency interval of 88MHz---98 MHz, the audio signals can be sent out and received with the small power in a long distance .The emissive power of the system is about 20mW and the emissive distance is more than 20m.There is no obvious distortion in the audio transmission.Key Words：frequency modulation；audio transmission；ROHM BH1415F目录1 引言 (1)1.1 通信的发展 (1)1.2 广播的发展现状 (1)1.3 设计思路 (2)2系统概述 (3)2.1 系统功能要求 (3)2.2系统组成 (3)3 方案论证与比较 (5)3.1 无线调频发射电路设计方案论证与选择 (5)3.2 压控振荡器方案论证与选择 (6)4 系统硬件电路的设计 (7)4.1 单片机控制电路 (7)4.1.1 内部结构 (7)4.1.2 引脚功能 (9)4.2 调频调制发射电路 (11)4.2.1 调频调制电路的特点 (11)4.2.2 结构图 (11)4.2.3 允许的最大值 (12)4.2.4 工作范围 (12)4.2.5 调频调制发射电路的组成 (12)4.3 键盘部分 (14)4.3.1 单片机键盘和键盘接口概述 (14)4.3.2 单片机键盘接口和键功能的实现 (15)4.4 LC振荡电路 (16)4.5 调频放大电路 (17)4.6 电源模块设计 (17)4.6.1 单元电源电路设计 (17)4.6.2 直流稳压电源的检测 (17)5 系统程序的设计 (18)5.1 主程序 (18)5.2 延时子程序 (19)5.3 LED动态扫描子程序 (19)5.4 频率数据转换子程序 (19)5.5 控制命令合成子程序 (19)5.6 BH1415F字节写入子程序 (20)5.7 查键子程序 (21)6 系统调试及性能分析 (23)6.1 硬件调试 (23)6.2 软件调试 (23)6.3 发射频率的调试 (23)6.4 性能分析 (23)结论 (24)参考文献 (25)附录1：原理图 (26)附录2：程序源代码 (28)附录3：英文原文 (41)附录4：中文译文 (52)致谢 (59)1 引言1.1 通信的发展人类社会的发展可视为一部信息传播技术的发展史。
RFMD RF3809 说明书
Optimum Technology Matching ® AppliedGaAs HBTInGaP HBTGaAs MESFET SiGe BiCMOS Si BiCMOSSiGe HBTGaAs pHEMTSi CMOS Si BJTGaN HEMT Functional Block DiagramRF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trade-mark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2006, RF Micro Devices, Inc.Product DescriptionOrdering InformationRF MEMSLDMOSGaAs HBT PRE-DRIVER AMPLIFIERThe RF3809 is a GaAs pre-driver power amplifier, specifically designed for wireless infrastructure applications. Using a highly reliable GaAs HBT fabrication process,this high-performance single-stage amplifier achieves high output power over a broad frequency range. The RF3809 also provides excellent efficiency and thermal stability through the use of a thermally-enhanced surface-mount plastic-slug pack-age. Ease of integration is accomplished through the incorporation of an optimized evaluation board design provided to achieve proper 50 Ω operation. Various evalua-tion boards are available to address a broad range of wireless infrastructure appli-cations: NMT 450 M Hz; GSM850 M Hz; GSM900 M Hz; DCS1800 M Hz;PCS1900 M Hz; and, UMTS2200 M Hz.FeaturesHigh Output Power of 2.0 W P1dB High LinearityHigh Power-Added Efficiency Thermally-Enhanced PackagingBroadband Platform Design Approach, 450 M Hz to 2500 M HzApplicationsGaAs Pre-Driver for Basestation AmplifiersPA Stage for Commercial Wire-less InfrastructureClass AB Operation for NMT, GSM, DCS, PCS, and UMTS Transceiver Applications2nd/3rd Stage LNA for WirelessInfrastructureRF3809GaAs HBT Pre-Driver AmplifierRF3809PCK-410Fully Assembled Evaluation Board, 450 M HzRF3809PCK-411Fully Assembled Evaluation Board, 869 M Hz to 894 M Hz RF3809PCK-412Fully Assembled Evaluation Board, 920 M Hz to 960 M Hz RF3809PCK-413Fully Assembled Evaluation Board, 1800 M Hz to 1880 M Hz RF3809PCK-414Fully Assembled Evaluation Board, 1930 M Hz to 1990 M Hz RF3809PCK-415Fully Assembled Evaluation Board, UMTS9Package Style: SOIC-8Absolute Maximum RatingsCaution! ESD sensitive device.Exceeding any one or a combination of the Absolute Maximum Rating conditions may cause permanent damage to the device. Extended application of Absolute Maximum Rating conditions to the device may reduce device reliability. Specified typical perfor-mance or functional operation of the device under Absolute Maximum Rating condi-tions is not implied.RoHS status based on EU D irective 2002/95/EC (at time of this document revision).The information in this publication is believed to be accurate and reliable. However, no responsibility is assumed by RF Micro Devices, Inc. ("RFMD") for its use, nor for any infringement of patents, or other rights of third parties, resulting from its use. No license is granted by implication or otherwise under any patent or patent rights of RFMD. RFMD reserves the right to change component circuitry, recommended appli-cation circuitry and specifications at any time without prior notice.Theory of Operation and Application InformationRF3809 design accommodates use in a variety of applications:•Linear driver from 450 M Hz to 2500 M Hz•2nd/3rd stage high linearity LNA, with noise figure in the 3 d B to 4 d B range from 800 M Hz to 2200 M Hz•High efficiency (> 50%) output stage for non-linear applicationsNominal data sheet shows specification for V CC=V BIAS=V REF=8V. RF3809 can easily be configured for 5 V operation, with a simple bias resistor change at V REF.. “Bias Table” on page 5 shows resistor values for V CC=V BIAS=V REF=5V. Generally speak-ing, 5 V data will compare to that for 8 V as follows:• 3 d B to 3.5 d B reduction in OP1dB•0.4 d B to 0.5 d B increase in small signal gainFor operation at other than 5 V, bias R can be calculated as follows (V CC=V BIAS=V REF=5V is used here to illustrate, operation at different voltage is determined with same methodology).e nominal 8 V case as a starting point: V CC=V BIAS=V REF=8V, I REF=15 m A, I CQ=258 m A. Target condition will be toachieve same I CQ with V CC=V BIAS=V REF=5V.ing evaluation board with separate lab supplies on (V CC/V BIAS) and (V REF), set V CC/V BIAS=5V, V REF=8V. I REF is main-tained at 15 m A, and I CQ drops from nominal value of 258 m A.3.V REF can then be increased > 8V until I CQ is restored. I REF increase to 23 m A is required (as seen in “Bias Table” on page 5).4.At this point, pin voltage at V REF is calculated (or measured with DVM): V PIN=V REF at eval board input – I REF*b ias R =10.8 –0.023 *300 =3.9 V.5.Next, calculate new bias R for V REF=5V: Bias R =(5 –3.9)/0.023 =47.8 Ω. See “Bias Table” on page 5, standard resistorvalue =47 Ω is called out. In this way, bias R can be calculated for any V CC=V BIAS=V REF configuration. The maximum I REF limit for RF3809 =30 m A.Junction-to-case thermal resistance (R TH_JC) is shown versus output power in the graph section of this data sheet. The graph was generated with nominal V CC=V BIAS=V REF=8V, I REF=15 m A, where ambient temperature =85 °C. Using this curve along with operating condition, junction temperature can be calculated. Resultant T J for this case yields MTTF ≥100 years. Standard RF3809 evaluation boards are matched for high efficiency at O P1dB. To ensure reliability for operation at high power, output match achieving equivalent or better efficiency on system board should be the goal.Typical s-parameter responses for each evaluation board are shown within the data sheet. These boards were matched with two specifications in mind:•Output load impedance set for optimum OIP3/ACP (Adjacent Channel Power for commonly used modulation standards).•Output load impedance set for high efficiency at O P1dB, with ruggedness (survival) into output 4:1 VSWR.In some cases, low power operation being one, it may be desirable to improve output return loss seen on evaluation board. This can be done with output match adjust. The result will be an increase in small signal gain. Tradeoffs between return loss, gain, OIP3, and compression point can then be considered in obtaining optimum performance for a particular application. Finally, infrastructure qualification report for RF3809 can be obtained by contacting RFMD.Package Drawing400 M Hz (RF3809410)Evaluation Board Schematic800 M Hz to 1000 M Hz (CDMA800, ISM, EGSM)869 M Hz to 894 M Hz (GSM800) (RF3809411)Evaluation Board Schematic920 M Hz to 960 M Hz (GSM900) (RF3809412)1805 M Hz to 1880 M Hz (DCS1800) (RF3809413)Evaluation Board Schematic1930 M Hz to 1990 M Hz (PCS1900) (RF3809414)UMTS (RF3809415)Evaluation Board Layout Board Size 2.0” x 2.0”PCB Design RequirementsPCB Surface FinishThe PCB surface finish used for RFMD's qualification process is electroless nickel, immersion gold. Typical thickness is 3 μinch to 8 μinch gold over 180 μinch nickel.PCB Land Pattern RecommendationPCB land patterns for PFMD components are based on IPC-7351 standards and RFMD empirical data. The pad pattern shown has been developed and tested for optimized assembly at RFMD. The PCB land pattern has been developed to accommodate lead and package tolerances. Since surface mount processes vary from company to company, careful process development is recommended.PCB Metal Land PatternPCB Solder Mask PatternLiquid Photo-Imageable (LPI) solder mask is recommended. The solder mask footprint will match what is shown for the PCB metal land pattern with a 2 m il to 3 m il expansion to accommodate solder mask registration clearance around all pads. The center-grounding pad shall also have a solder mask clearance. Expansion of the pads to create solder mask clearance can be provided in the master data or requested from the PCB fabrication supplier.Thermal Pad and Via DesignThe DUT must be connected to the PCB backside ground through a low inductance, low thermal resistance path. The required interface is achieved with the via pattern shown below for both low inductance as well as low thermal resistance. The footprint provided below worked well on the RFMD 20 m il thick Rogers 4350 PCB and also standard FR4. The vias are 8 m il vias that are partially plated through and are finished to 8 m ils ±2 m ils with a minimum plating of 1.5 m il. Failure to place these vias within the DUT mounting area on the PCB in this prescribed manner may result in electrical performance and/or reliability degrada-tion.Tape and Reel InformationCarrier tape basic dimensions are based on EIA 481. The pocket is designed to hold the part for shipping and loading onto SMT manufacturing equipment, while protecting the boyd and the solder terminals from damaging stresses. The individual pocket design can vary from vendor to vendor, but wide and pitch will be consistent.Carrier tape is wound or placed on a shipping reel with a diameter of either 330 m m (13 i nches) or 178 m m (7 i nches). The cen-ter hub design is large enough to ensure the radius formed by the carrier tape around it does not put unnecessary stress on the parts.Prior to shipping, moisture sensitive parts (MSL level 2a to 5a) are baked and placed into the pockets of the carrier tape. A cover tape is sealed over the top of the entire length of the carrier tape. The reel is sealed in a moisture barrier, ESD bag, which is placed in a cardboard shipping box. It is important to note that unused moisture sensitive parts need to be resealed in the moisture barrier bag. If the reels exceed the exposure limit and need to be rebaked, most carrier tape and shipping reels are not rate as bakeable at 125°C. If baking is required, devices may be baked according to section 4, table 4-1, column 8 of Joint Industry Standard IPC/JEDEC J-STD-033A.The following table provides useful information for carrier tape and reels used for shipping the devices described in this docu-ment.Carrier Tape Drawing with Part OrientationRF3809RF3809。
关于无线信号的英语作文
关于无线信号的英语作文Title: Exploring the World of Wireless Signals。
In our modern world, wireless signals play a crucial role in facilitating communication and connectivity. From Wi-Fi to Bluetooth, these invisible waves transmit data across various devices, enabling seamless interactions in both personal and professional spheres. In this essay, we delve into the fascinating realm of wireless signals, exploring their mechanisms, applications, and impact on society.Firstly, let's understand the fundamentals of wireless signals. At its core, wireless communication relies on electromagnetic waves to transmit information between devices without the need for physical cables. These waves travel through the air or other mediums, such as water or space, carrying data encoded in the form of radio, microwave, or infrared signals.One of the most ubiquitous forms of wireless communication is Wi-Fi, which enables internet access in homes, businesses, and public spaces. Wi-Fi operates within the radio frequency spectrum, typically at frequencies of 2.4 GHz or 5 GHz, allowing devices to connect to a local network and access the internet wirelessly. This technology has revolutionized how we access information, enabling usto stay connected anytime, anywhere.Bluetooth is another popular wireless technology that facilitates short-range communication between devices, such as smartphones, tablets, and wearable gadgets. It operates within the same frequency range as Wi-Fi but focuses on establishing connections over shorter distances, typically within a range of 10 meters. Bluetooth is commonly used for tasks like file sharing, wireless audio streaming, and device synchronization.Apart from Wi-Fi and Bluetooth, there are numerousother wireless technologies serving diverse purposes. Cellular networks, for instance, utilize radio waves to provide mobile phone coverage over large geographical areas.GPS (Global Positioning System) relies on satellite signals to determine the precise location of devices, enabling navigation and location-based services. NFC (Near Field Communication) enables contactless communication between devices in close proximity, facilitating mobile payments and data exchange.The proliferation of wireless signals has led to a myriad of applications across various industries. In healthcare, wireless technology enables remote patient monitoring, wearable health trackers, and telemedicine services, improving access to healthcare and enhancing patient outcomes. In transportation, wireless communication is integral to autonomous vehicles, enabling them to communicate with each other and infrastructure to ensure safe and efficient operation.Moreover, wireless signals have transformed the way we interact with our surroundings. Smart homes leverage wireless technology to control appliances, lighting, security systems, and entertainment devices remotely, enhancing convenience and energy efficiency. In education,wireless connectivity in classrooms facilitatescollaborative learning, interactive teaching methods, and access to online resources, enriching the educational experience for students.Despite its numerous benefits, the widespread use of wireless technology also raises concerns regarding security, privacy, and electromagnetic radiation. Cybersecurity threats, such as hacking and data breaches, pose risks to wireless networks, emphasizing the importance of implementing robust security measures. Additionally, some studies suggest potential health risks associated with prolonged exposure to electromagnetic fields emitted by wireless devices, although scientific consensus on this issue remains inconclusive.In conclusion, wireless signals have revolutionized communication, connectivity, and everyday life. From Wi-Fi and Bluetooth to cellular networks and GPS, these invisible waves enable seamless interactions between devices and empower individuals and organizations with unprecedented capabilities. As we continue to embrace wireless technology,it is essential to address associated challenges responsibly while harnessing its potential to create a more connected and intelligent world.。