卫星链路计算软件Satmaster帮助

上下行部分

Site Name / Location

Enter the literal name of the site where the earth station is located up to a maximum of 40 characters (18 for country data files)

Example input for country data files (18 characters maximum)

"Liverpool"

Example input for all other forms (40 characters maximum)

"Liverpool, Merseyside, England."

基站名称

输入基站所处位置的名称，最多40个字母。

国家数据文件名举例（最多18个字母）：liverpool

其他格式输入举例："Liverpool, Merseyside, England."

Site Latitude

Enter the latitude of the site where the earth station is located. This must be entered in decimal degrees with the suffix N for north and S for South. No spaces are allowed. Examples 53.33N or 27.89S

Important Note:

When entering data into country data files latitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the fractional part represents the number of minutes and cannot exceed 59. In all other cases input in decimal degrees are assumed. A conversion facility is provided under the calculate menu.

基站纬度

输入地面站的纬度。必须以小数后跟N或S表示。不能输入空格。比如53.33N或27.89S 注意事项

当输入国家数据文件时纬度需要以地图上的度和分为单位。这种情况下，小数部分为分的表示，不能超过59。在其他情况下，都是以度来表示的。Caculate菜单中有一个转换工具。

Site Longitude

Enter the longitude of the site where the earth station is located. This must be entered in decimal degrees with the suffix W for west and E for East. No spaces are allowed. Examples 3.00W or 29.79E

Important Note:

When entering data into country data files longitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the fractional part represents the number of minutes and cannot exceed 59. In all other cases input in decimal degrees are assumed. A conversion facility is provided under the calculate menu.

基站经度

输入基站的经度。必须以小数后跟E或W表示。不能输入空格。比如3.00W 或29.79E

注意事项

当输入国家数据文件时纬度需要以地图上的度和分为单位。这种情况下，小数部分为分的表示，不能超过59。在其他情况下，都是以度来表示的。Caculate菜单中有一个转换工具。

Altitude of Site

Enter the altitude of the earth station above sea level. This is primarily used in the calculation of rain attenuation and atmospheric absorption. The units are kilometres.

5.0 km is the maximum altitude allowed. Enter zero if you will prefer a slightly pessimistic worst case link budget calculation.

基站海拔

输入基站的海拔。这主要是用来计算雨衰和大气吸收值，单位是千米。

最大允许输入的海拔为5km。如果需要比较悲观链路预算可以输入0。

Frequency

频率

Enter the centre frequency of the carrier in GHz. For the uplink, typical values are around 6GHz and 14GHz for C and Ku band respectively. For the downlink, values of 4GHz and 12GHz are typical. The accepted range is 1GHz to 50GHz

输入上行载波的中心频率，以Ghz为单位。典型C波段和Ku波段的值为6GHz和14GHz。下行的典型频率为4Ghz和12GHz。可输入的范围为1Ghz到50GHz。

Polarization

This is simply the polarization system adopted by the wanted satellite transponder and is either linear (ie vertical & horizontal) or circular. Enter the letter "V" for vertical polarization, "H" for horizontal polarization or "C" for circular polarization.

极化

这就是所需卫星转发器的极化方式，可以选线性（垂直和水平）或圆极化。输入“V”为垂直极化，“H”为水平极化，“C”为圆极化。

Signal Availability

Depending on your system design requirements a choice of signal availability should be specified. For typical domestic satellite TV systems, a figure of 99.5% availability is normally sufficient. In fact most packaged fixed dish systems are designed around this figure. For SMATV you may require a higher figure of 99.9% and cable head even higher. The upper limit provided is 99.999% but this level of performance is rarely necessary or even achievable. The parameter is used in calculating an appropriate fade margin based on the rain-rate statistics for the site. If you like to work with "worst month" statistics a conversion to "average year" signal availability is provided under the "Calculate" menu.

With link budgets using uplink power control systems a higher availability is often specified for the uplink than the downlink.

信号可用度（年平均）

根据你的系统设计需求，信号可用度应该是确定的。典型的国内TV系统，这个数到99.5%为宜。实际上大多集成的碟形天线系统按照这个数字设计。SMATV（卫星公共接收电视）需要高到99.9%的可用度，电视终端机则更高。最高可以设为99.999%但是这种程度的可用度不常用也不可行。这个数值经常用来计算合适的雨衰。如果你愿意通过“worstmonth最糟糕的一个月”数值转换为年平均信号可用度，可以通过Calculatec菜单下的工具进行换算。如果链路使用上行功率控制系统，经常要设置一个较高的系统可用度。

Antenna Aperture

Antenna aperture is normally taken as the overall diameter of a parabolic dish, the major dimension if an offset focus antenna. Units are always metric (in metres) to conform to international engineering practice. The lower limit handled is 0.2 metres and the highest 50 metres.

天线口径通常是抛物线天线的直径，偏馈天线的主要直径。单位都是米。最少为0.2米，最大为50米。

Antenna Efficiency

Antenna efficiency is the amount of incident signal actually collected by the dish and feed, expressed as a percentage. Quality of construction, signal blockage by head units, and method of feed affects this parameter. Most antennas have efficiencies of between 60% and 70%. If you do not know the efficiency of the antenna then enter 60% as a worst case value.

With link budget and dual feed forms, the value entered may be prefixed with a "+" character so the value will be interpreted as a gain, in dBi, rather than efficiency.

天线效率

天线效率就是入射信号呗反射面和馈源收集到得数量，表示为一个百分比。建设施工质量，前馈部分的遮挡还有馈源材料会影响这项参数。多数天线的效率在60-70%之间。如果你不

知道则输入60%作为最悲观估计

在链路预算和双馈形式中，这个值必须加一个“+”前缀以便程序将其解读为增益，以dBi 为单位，而不是天线效率。

Coupling loss

This parameter is the total loss due to the insertion of waveguide components and polarizers. Values are expected in dB and are typically in the order of 0.3dB. You should add all the insertion losses of waveguide components, such as OMTs and polarizers, that you intend to use.

耦合衰减

这个数值是波导原件、偏振器引起的一切衰减。单位是dB，典型值为0.3dB。你应该输入整体的波导元器件的衰减，如OMT和偏振器。

Antenna misspointing loss

This parameter allows for the pointing loss between the ground station antenna and the satellite antenna. It is unlikely in practice that the antenna will be targeted exactly due to initial installation errors, factors such as the stability due to wind and the station keeping accuracy of the satellite. A large antenna, having a narrow beamwidth and being relatively unstable in wind inherit a disadvantage over a small one.

A typical allowance for mispointing is 0.3 dB. This may need to be increased to 0.5d

B for very large antennas particularly in windy areas.

天线偏离损耗

这个数值是对星不准引起的地面站和卫星间的损耗。实际中因为初始安装误差，很难将天线完全对准卫星，如风稳和地面保持精度等因素。大型天线发射窄波束时会相对于小天线更加不稳定。

典型值为0.3dB。大型天线处于多风地带的话可能需要加到0.5dB.

LNB Noise Figure (LNB Noise Temperature)

The default interpretation of this input parameter is Noise Figure. However, if you prefix the input value with a '+' character it will be automatically interpreted as a Noise Temperature instead.

It is conventional to quote the noise figure of an LNB in dB for Ku and Ka bands and the equivalent noise temperature in Kelvin for S and C bands. It is usually more difficult and expensive to achieve low noise figures the higher the frequency. For Ku-band low cost LNB's are in the range 0.8dB to 1.0dB or 30K for C band.

Note: We use the term "LNB" in the generic sense here, LNA, LNC etc is equally valid.

LNB噪声

默认的解读法是读为噪声因数，但如果在数值前加上“+”号则程序将其读为噪声温度。

通常使用噪声因数表示Ku和Ka波段的LNB噪声，噪声温度表示。频率越高，通常来讲就越难以达到很低的噪声。比如Ku波段比较便宜的LNB噪声都是在0.8-1.0dB，C波段的通常为30K。

Antenna noise temperature

A value for the antenna noise temperature is often quoted in manufacturer's specifications. The total noise temperature of the antenna depends mainly on the following factors:

1) Sky Noise The total antenna noise, Tant = Tsky+Tgnd. The sky noise, Tsky, consists of two main components, absorption and the background 'big bang' radiation (2.7K). Since the atmosphere is an absorbing medium it must be a noise source so sky noise increases with decreasing elevation due to the longer path through the atmosphere.

2) Ground Noise The dominant contribution to antenna noise at low elevations is ground noise pick up through side lobes. Noise temperature increases as the elevation angle decreases since the antenna will pick up more ground noise due to side lobes intercepting the ground (diffraction effects at the antenna rim). This may be reduced by various methods of feed illumination and the dish design itself. A deep dish picks up less ground noise at lower elevations than do shallow ones also prime focus mounted head units will add to noise since it is "seen" at the same temperature as the Earth.

Estimating Antenna Noise Temperature

Since antenna noise temperature has so many variable factors, an estimate is perhaps the best we can hope for. In the absence of a specific manufacturer supplied figure, a reasonable estimate may be obtained by selecting Calculate|Estimate Antenna Noise Temperature from the menu.

天线噪声温度

天线的噪声温度通常标注在厂家的说明书中。天线的总噪声主要受以下几个方面影响：

1）天电噪声。天线的总噪声=天电噪声+地电噪声。天天电噪声，Tsky，包含两部分，空气吸收和大爆炸背景辐射。因为大气是一种（电磁波）吸收媒介所以肯定会有噪声。所以海拔降低大气噪声就会增加，因为在电磁波在大气中传播的更远。

2）大地噪声。在低仰角的情况下对天线噪声影响最大的是旁瓣吸收的大地噪声。天线仰角降低，大地噪声就升高（天线的衍射效果）。它有可能通过馈源和反射面的特殊设计而减小。比较凹的天线反射面会减少大地噪声，而天线头部分也会增加噪声，因为它也可以看作和大地有一样的噪声。

估算天线噪声温度

因为天线噪声温度受很多因素影响，我们只好算出一个估计值。如果没有厂家提供的参数，使用Calculate->Estimate Antenna Noise Temperature进行计算。

Adjacent Channel Interference C/ACI

相邻信道干扰

Enter a value for the carrier to adjacent-carrier interference noise ratio C/ACI in dB. This parameter specifies the expected interference level with respect to the wanted carrier. A typical value to enter for either uplink or downlink is between 24 and 30dB. Some link programs do not use this parameter so if you wish to void it enter 60dB or more. Note that the higher this value is in dB, the lower the interference.

输入一个相邻信道干扰噪声C/ACI，以dB为单位。这个参数指定一个所需载波的干扰程度。上行和下行的典型值在24-30dB之间。很多工程不需要这些参数，如果不希望考虑它，输入60dB以上的值。注意这个值越高表示干扰越小。

Adjacent Satellite Interference C/ASI

相邻卫星干扰

Enter a value for the carrier to adjacent satellite interference noise ratio due to interfering signals to/from adjacent satellites in dB. This parameter specifies the expected interference noise with respect to the wanted carrier..A typical value to enter here for either uplink or downlink is between 18 and 30dB. Note that the higher this value is in dB, the lower the interference.

输入一个相邻卫星干扰噪声C/ASI，以dB为单位。这个参数指定一个所需载波的干扰程度。上行和下行的典型值在18-30dB之间。注意这个值越高表示干扰越小。

Cross Polarization Interference C/XPI

极化干扰

Enter a value for the carrier to cross polarization interference noise ratio C/XPI in dB. This parameter specifies the expected interference level with respect to the wanted carrier. A typical value to enter here for either uplink or downlink is between 24 and 30dB. Note that the higher this value is in dB, the lower the interference.

输入一个交叉极化干扰噪声C/XPI，以dB为单位。这个参数指定一个所需载波的干扰程度。上行和下行的典型值在24-30dB之间。注意这个值越高表示干扰越小。

Earth Station HPA Output Back-Off

地球站高功放输出回退

To reduce uplink interference it is customary to back off the output of the earth station HPA. This trade-off leads to a higher HPA power capability being required. Typical values range from 1 to 7dB.

为了防止上行的噪声一般要对地球站的高功放进行回退。这种权衡的做法会导致需求功放的功率变大。典型值在1-7dB之间。

Number of HPA Carriers

高功率放大器载波数量

Enter the number of carriers simultaneously transmitted by the uplink earth station HPA. Normally this is set to 1 unless you need to size the HPA for multiple carriers. This has no effect other than to increase the HPA power requirement.

输入地球上行功率放大器同时传输的载波数量。如果不需要同时传多个载波的话就输入1。这个数值只会影响功率放大器的功率需求。

HPA Intermodulation Interference C/IM

功放交调干扰

Enter a value for the intermodulation interference expected from the uplink earth station HPA. This parameter is sometimes neglected in many programs. If you wish to make this parameter effectively void enter 60dB or more.. Note that the higher this value is in dB, the lower the interference level.

输入一个上行功放交调干扰值，以dB为单位。很多工程不需要这些参数，如果不希望考虑它，输入60dB以上的值。注意这个值越高表示干扰越小。

Uplink Power Control / Manual Power Boost

上行功率控制/手动功率控制

Uplink Power Control (UPC) also known as Dynamic Carrier Control is used to compensate for instantaneous rain attenuation on the uplink. Enter the dynamic range of the system here. If UPC is not used or site diversity plans are in operation you can enter zero here. UPC systems usually require a high HPA power capability.

上行功率控制（UPC）又叫动态载波控制，是用来抵消上行偶尔的雨衰。输入动态的系统变化值。UPC系统需要更大的功放功率。

雨衰Rain models

Here you can select the rain model to use. Check the checkbox relevant to the model you wish to use.

The ITU/DAH rain model is recommended since it is probably the most accurate model to date. The Crane models are also provided if you prefer them. You do not need to consult rainzone maps with the latter, the zones are determined automatically.

The ITU/DAH model employs a 1.5*1.5 degree lat/long grid of R0.01 rainfall data and uses bilinear interpolation to achieve an improved estimate for a location from it's grid neighbours.

Although not normally necessary, a better accuracy may result with the ITU/DAH model if a localized R0.01 value is obtained. To use this, check the checkbox labelled "ITU mm/h" then enter your locally obtained R0.01 value into the input field below it. A value of zero may be input if you wish to temporarily remove any rain effects from the budget..

Note: This option is not available for items under the 'Graphs' and 'Tables' menus.

Dual Fade Checkbox (only present on some link budget forms)

Where uplink and downlink stations are separated by several km, it is not normally assumed there is a rainstorm on the uplink and downlink simultaneously as this is statistically unlikely. However, if the uplink and downlink are in the same city or an area which may be covered by a large tropical storm, you may like to check this checkbox so rain attenuation is calculated both on the uplink AND downlink simultaneously. In general, Ku band is not so suitable as C band for tropical regions due to high rain attenuation.

你可以在这里选择雨衰模型。选择相关的复选框即可。

推荐使用ITU/DAH雨衰模型，因为它应该是最精确的模型。Crane模型也可以使用，这种模型你无须寻找降雨地图，系统会自动计算。

ITU/DAH使用1.5*1.5经纬度的方格来统计各地区的R0.01降雨数据，而且使用双线性插值法来得到更精确的估计。

虽然通常不必要，但是如果有相关r0.01数据的话ITU/DAH是更精确的。点选ITU mm/h来手动输入R0.01值。如果不想计算雨衰值可以输入0.

注：这个值是不能在Graph或者Table里面查的。

双重雨衰选项（只有一部分链路预算需要）

如果上下行站相距几千米，一般上行下行同时下雨的情况为统计上的不可能。但是如果上下行在同一个城市或者地区，可能受同一个降雨云影响，你可能需要计算上行和下行同时受到雨衰的影响的情况。因为雨衰，Ku波段总体来讲不如C波段适合热带地区的通信。

卫星部分satellite

Transponder Type Radio Buttons

转发器种类

These radio buttons set the transponder type, which can be either a TWTA (Traveling Wave Tube Amplifier) or SSPA (Solid State Power Amplifier). The default is TWTA. This is used in determining typical values for output back-off and transponder intermodulation interference if the AUTO mode is selected.

这个单选按钮设置转发器种类，可以是TWTA(Travelling Wave Tube Amplifier)或SSPA(Solid

State Power Amplifier)。默认是TWTA。在AUTO模式下，它用来计算输出回退的典型值和转发器的交调干扰。

Satellite Name

卫星名称

Enter the literal name of the target satellite up to a maximum of 40 characters. (18 for satellite data records)

Example Astra 2a

输入卫星名称，不超过40字符。（卫星文件记录不超过18个字符）

如Astra 2a

Satellite Longitude

卫星经度

Enter the longitude corresponding to the sub-satellite point of the satellite on the equator. This should be in decimal degrees with the suffix E for East and W for West. Examples 19.2E or 125.00W

输入该卫星赤道星下点的经度。这个值是10进制的小数，单位是度。如19.2E或125.00W。

Satellite G/T

Enter the Figure of Merit (G/T) of the on board satellite receiver in units of dB/K. This should be the value in the direction of the earth station. Values may be obtained from satellite operators or satellite directories in the form of G/T contour maps.

输入卫星接收器的品质因数G/T，这个值应该是地球站地理位置所对应的那个值。它可以在卫星运营商的G/T等高线图那里得到。

Satellite Saturation PFD(SFD)

卫星饱和通量密度

Enter the Saturation Flux Density (SFD) value, in dBW/m2, required to saturate the satellite's transponder from the earth station. The program assumes this input value corresponds to a reference 0dB attenuator pad setting here. SFD can be thought of as the input sensitivity of the transponder where the more negative the value the higher the sensitivity. (Example: -89 dBW/m2)

Some satellite operators do not supply SFD contour maps, in which case the SFD(effective) at a specific site may be deduced using the following simple expession:

SFD(effective) = SFD(ref) - (G/T - G/T(ref))

where

SFD(ref) and G/T(ref) can be any known pair of reference values such as beam peak or beam edge.

When the transponder is operated in power limited mode for multi-carriers it is common practice for the satellite operator to set the attenuator pad to a nominal 10dB or 16dB to increase the number of carriers the transponder can support at the expense of earth station uplink power. The attenuator pad, commandable from the ground, affects all carriers sharing the transponder. Important Note: Some satellite operators specify the SFD at a nominal attenuator pad setting typically, 10dB or 16dB.. You should always enter the SFD assuning the reference attenuator pad setting is 0dB here. The attenuator pad may be set separately to 10dB or 16dB within the program. You can, of course, set the SFD at any given attenuator pad setting but if you do, you must set the attenuator pad input field to 0dB. If in any doubt contact your satellite operator for SFD and attenuator pad settings.

输入饱和通量密度（Saturation Flux Density）值，单位是dBW/m2，这个值是使卫星转发器达到饱和的通量密度。程序会认为这个值是对应衰减器为0dB情况。SFD可以看做一个输入的敏感度。这个值越小敏感度越高。

有些卫星运营商不提供SFD等高线图，SFD可以由以下公式算出。

SFD(effective) = SFD(ref) - (G/T - G/T(ref))

SFD(ref) and G/T(ref)可以是任意一对值比如波束中心或者波束边缘值。

当转发器工作于功率限定模式的多载波模式，卫星运营商经常将衰减跳到10dB或16dB来增加支持的载波数，这会增大地球站上行的功率。衰减器可以在地球上控制来改变转发器支持的载波数。

提示：有些运营商给的SFD数据是加了他们常用的衰减10dB、或16dB。但这里需要输入衰减为0的情况。衰减器10dB或者16dB是在程序的其他地方进行设置的。你也可以输入衰减器为任何dB的情况，但这是就要把衰减器设为0dB。如果对SFD和衰减有疑问，和你的卫星运营商联系。

Satellite Attenuator Pad Setting

卫星衰减器设置

Enter the value of the attenuator pad setting in dB. This is set by the satellite operator for the transponder depending on it's use. This program assumes you have entered the SFD corresponding to an attenuator setting of 0dB and adds this value to it.

Example: Suppose the SFD, with 0dB attenuator pad setting is given as -90dBW/m2. The overall SFD with the 10dB attenuator pad included is, -90dBW/m2 +10dBW/m2 = -80dBW/m2)

Important note: If you have already allowed for a nominal attenuator pad setting in the SFD input field you must set this parameter to 0dB otherwise you could severely over dimension the link.

输入卫星衰减器衰减，以dB为单位。这个值是卫星运营商根据需要设定的。这个程序默认你输入的SFD中不包括卫星衰减器的衰减。

举例：比如SFD在0dB衰减的时候为-90dBW/m2。总的SFD在10dB衰减的情况下就是-80dBW/m2

注意：如果SFD中已经考虑了卫星衰减器，这个值要设为0。否则这个链路计算会错误。

Satellite ALC

卫星ALC（Automatic Level Control）

On some satellites, there is an option for a transponder to be switched from conventional fixed gain mode to an AGC system known as Automatic Level Control. This helps to reduce the effects of uplink rain by setting a constant drive level into the TWTA regardless of any input carrier signal fluctuations thus maintaining a constant downlink EIRP. ALC works best with one saturating carrier within the transponder where the uplink C/No is at least 10dB greater than that of the downlink. .ALC is not suitable for multicarriers per transponder use. Once the ALC range is exceeded by an uplink rain fade, the downlink EIRP begins to fall.

Enter the dynamic range of the, on-board, Automatic Level Control in dB used in compensating for rain on the uplink. If ALC is not used enter zero.

有些卫星的转发器可以从固定增益模式转到AGC自动增益控制系统。这样可以减小上行雨衰的影响，不论受到的载波大小，TWTA电平固定，发射的EIRP总是固定的。ALC最好用于上行C/N0大于下行10dB以上的饱和载波。ALC也不适用于转发器的多载波使用。当雨衰的量超过了ALC范围，下行EIRP就会降低。

输入卫星的上行ALC补偿范围。如果不使用则输入0.

Satellite EIRP (saturation)

卫星EIRP（饱和）

Enter the full transponder's effective isotropic radiated power output, at single carrier saturation, in the direction of the earth receive station.

输入地面接收站位置的转发器饱和EIRP值，在单载波饱和的情况。Transponder Bandwidth

转发器带宽

Enter the satellites full transponder bandwidth. This is typically 24MHz, 27MHz, 36MHz or 72MHz or more.

输入卫星转发器带宽。典型值有24MHz, 27MHz, 36MHz or 72MHz等。Transponder Input Back-off (IBO)

转发器输入回退IBO

This parameter is set to the total transponder input back off, or operating point, relative to single carrier saturation. Most satellite transponders operating in multicarrier mode (e.g. SCPC carriers sharing the same transponder) will operate with an input back-off within the range 6 to 10dB to

reduce intermodulation interference and/or to limit the downlink EIRP density within certain agreed limits.

.这个参数是转发器输入回退，或者说工作点，相对于单载波饱和发送。多数的卫星转发器使用多载波模式会进行一个输入回退，大概是6-10dB，来减少交调干扰，也有时用于限制下行EIRP。

Transponder Output Back-off (OBO)

转发器输出回退

这个数值是转发器的输出回退，相对于单载波饱和调制。它和输入回退有关。一对（输入回退和输出回退）值可以从卫星运营商处得到。典型值是0-4dB，比多载波转发器的输入回退小。

输入“AUTO”会根据典型的TWTA或者SSPA放大器的参数进行自动计算。如果输入AUTO，相应的交调也会自动计算。换句话说，这两个值是自动计算中成对生成的。

注意：

1）自动计算只是用于多载波模式的转发器，功率限定模式。如果是单载波转发器，输入手动值。通常对于单载波也是符合的，除非卫星运营商设定了特定的IBO和OBO值来限制下行EIRP密度。

2）如果转发器使用线性器时请使用手动值，此时IBO和OBO值有1对1的对应（比如IBO=8dB，OBO=8dB）

Transponder Intermodulation Interference C/IM

转发器交调干扰

这个值是载波间的交调干扰，单位是dB。它取决于中心频率、以及使用该转发器的其他载波确切的数量、种类、位置等。这些数据很难得到。增加输入回退也会减小交调干扰。

如果你无法得到输出回退或者交调干扰的确切值就输入AUTO让程序根据典型的行波管放大器和固态放大器参数自行估算两个值。如果这两个值（C/IM,IBO）有一个设为AUTO则使用系统计算的值。换句话说，这两个值是成对计算的。

注意：

1）AUTO只是用来计算多载波转发器在功率限定的情况下的值。单载波转发器需要手动输入值。它通常也适用于单载波饱和转发，除非卫星经营者设定了特殊的IBO，OBO对来限制下行EIRP。但是如果想要在AUTO模式下计算单载波转发器，C/IM增到60dB（实际等于没有干扰）。只有在IBO<3dB的情况下会产生这种情况。你应该在以后重新修改精确这一数字。2）C/IM在转发器未100%利用的情况下会有一定的改善。AUTO模式已经考虑了这方面因素。3）如果转发器上只有一个载波，你应该输入一个相对高的值，比如30dB-60dB，这样这个值对结果几乎没有影响。请注意这个值越高干扰越低。

Number of Carriers Sharing Transponder

转发器载波数量

In most cases AUTO is recommended here unless you know the number of similar carriers sharing the transponder in advance. For example, with single carrier per transponder usage you could enter, 1. If you do set the number of carriers manually you may also use the downlink optimization feature.

Important Notes:

1) The "HPA power capability" input, under the uplink tab is hidden if a manual value is entered.

2) The downlink optimization radio buttons are hidden with the AUTO oprion.

多数情况下这个值填AUTO。除非你已经知道转发器上载波的数量。比如，转发器上只有一个载波，输入1.如果手动输入了这个值，你也许也要输入下行优化特性。

注意

1）如果手动输入该值，上行链路中的“功放功率容量”会隐藏。

2）在AUTO模式下下行优化选项是隐藏的。

载波和调制部分Carrier and Modulation

Service name

服务名称

Enter the literal name of the satellite service or the customers name.

输入卫星服务名称或者用户名称。

Coverage

覆盖区域

Enter a literal name for the coverage of the service. e.g. spot, hemi, conus etc.

输入服务的覆盖区域名称，比如点覆盖，半球覆盖，美国本土覆盖等等。

Required Overall Eb/No

整体Eb/N0需求

Enter the overall value of Eb/No required for the link. This should include the demodulator implementation margin and group delay margin. Typical values are given under 'Graph | Reference Eb/No Curves. When multicarriers are sharing the same transponder the link budget is iterated to this target value plus any added system margin that is entered.'

Remember, that you can cancel the form to view any other data provided without losing what you have already entered. To reinstate the form just click the EDIT button.

输入链路的整体Eb/N0需求。这应该包括解调器解调余量和群延时余量。典型值在Graph->Reference Eb/No Curves

计算出。当多个载波公用一个转发器时，链路预算将叠加到这个值上再加上的其他一切的系统余量。

谨记，你可以按cancel退出界面来浏览其他的数据，其中已经输入的内容不会因此丢失。再按EDIT键就可以恢复界面。

Information rate

信息速率

Enter the information rate of the data in Mbps. For example 0.064 would be entered for 64kbps data.

输入信息速率，单位为Mbps。举例0.064就是64kbps的数据。

Overhead

系统开销（数据速率的百分比）

This is the amount of "overhead" added to the information data rate to account for miscellaneous signalling requirements and initialization of modems. This is typically expressed as a percentage of the information rate. This parameter may be given as a fixed value, in which case it must be converted into a percentage before input. You can enter zero here if unkown.

这是“包头”在数据信息速率中的数量。包头是用来负责多种信号制式需求和调制解调器的初始化。它一般表示为信息速率的百分比，你可能有的只是实际值，在这种情况下它必须转换成百分比才可以输入。如果不清楚可以输入0。

Forward error correction.

FEC率。FEC Code Rate。

Enter the inner code rate used with forward error correction. Typical values are 0.5 for BPSK and 0.75 or 0.875 for 4-PSK (QPSK).

输入前向纠错的内部码率。典型值BPSK为0.5,QPSK为0.75或0.875.(注，只是典型值，可以随便设)

Spreading Gain

扩频增益

Enter the spreading gain in the range 0dB to 100dB. This parameter is only relevant to spread spectrum transmission, in all other applications set this parameter to zero.

输入传播增益，范围为0-100dB。这个参数之和扩频传输有关，在其他的应用情况下设为0。

RS Code

RS码

Enter the Reed Solomon outer code (n/k). This can be either entered either as an expression, for example 204/188 so the program will evaluate it at run time or you can enter a specific value, for example, the equivalent 1.0851064. The former is perhaps the easiest method.

If you are not using RS coding simply enter a value of 1. This is the value set by default for backward compatibility with some previous versions which did not have a separate RS code input.

The numerator term, n, is the protected package length in bytes.

The denominator term, k, is the transport package length, or payload, in bytes.

The RS code can vary according to the system for example,

DVB-S = 204/188

Hughes DSS = 146/130

IBS = 126/112

Reed Solomon codes are used to correct burst errors and are frequently given in the literature in the following typical form:

RS[204,188, t=8]

where n=204 and k=188. The term t=8 just signifies that the code is capable of correcting up to 8 bytes per packet and is not relevant here.

输入里德-所罗门外部码（n/k）。这个数字可以以分数输入，比如204/188，程序会自动在运行时计算。或者你也可以输入一个小数，比如相应（204/188）的1.0851064。前者一般是比较简单的方式。

如果你没在使用RS编码这个值只需输入1.这是之前没有RS码输入的版本向后兼容默认输入的值。

分子n，为受保护的包长字节。

分母k，为传输的包长，或者说负载，以字节计。

不同的系统ＲＳ码率不同。比如

DVB-S = 204/188

Hughes DSS = 146/130

IBS = 126/112

ＲＳ码用来纠正突发的传输错误。它经常以如下方式表示：RS[204,188, t=8]

当ｎ＝２０４，ｋ＝１８８．数值ｔ＝８只表示这个编码每个包可以纠正８字节，和我们的计算不相干。

1+Rolloff factor

1+滚降系数

The roll off factor for a digital filter is typically expressed as a figure less than unity. However the actual factor used to expand the bandwidth is (1 + roll off factor).

Ranges between 1.15 to 1.3 are frequently used here. If in doubt, enter a nominal value of 1.2. Note: The bandwidth used by a digital carrier is proportional to the symbol rate, not the bit rate. 数字滤波器的滚降系数通常表示为一个图形。但是实际使用中计算扩展的带宽为（１＋滚降系数）。

该参数常用1.15-1.3。如果不清楚，输入一个1.2的标称值。

数字载波的带宽和它的符号率成正比，不是比特率。

Carrier Spacing Factor

载波分隔系数

For shared transponders, the allocated bandwidth is often greater than the occupied bandwidth of a carrier. This is to minimize adjacent carrier interference and to allow for minor fluctuations in the carrier's centre frequency.

A typical value to enter is 1.4 for multicarriers sharing the same transponder. If you do not require any carrier spacing, enter the same value as you entered for (1+ roll-off factor).

You cannot enter a value less than that entered for (1+roll off factor) as both factors are applied to the symbol rate. Be careful here because some programs apply this factor to the occupied bandwidth and not the symbol rate.

Note: The bandwidth used by a digital carrier is proportional to the symbol rate.

共用转发器时，分配的带宽一般比载波所占的带宽要大。这是用来减小相邻载波的干扰并允许载波中心频率小幅度的偏移。

多载波共用转发器的典型载波分割系数为1.4.如果你不需要载波分隔，输入值设为“1+滚降系数”的值。

不能设小于“1+滚降系数”的值，因为两个值会影响最终的符号率。注意，有的程序中这些值会影响占用带宽而非符号率。

Bandwidth Allocation Step Size

带宽分配块大小

Satellite operators sometimes charge for multiples of a fixed unit of allocated bandwidth. When estimating the amount of transponder bandwidth to lease or rent, the allocated bandwidth is normally rounded up to the nearest whole allocation unit. For example, a typical bandwidth charging step is 100kHz, since this program always requires input in MHz you would enter 0.1MHz. If you do not require this rounding up process then just enter zero.

天线运营商有时将频带分成固定带宽的块进行过按块收费。计算转发器租用带宽数量时，非配的带宽通常向上取整于最近的分配快。比如说，典型的带宽分配块大小为100kHz，因为本程序的单位为MHz你应该输入0.1MHz。如果你不需要向上取整过程只要输入0.

System Margin

系统余量

Although the program calculates industry standard rain fade margins and includes them in the link budget, it is customary to include an overall system margin to account for uncertainty in the various input parameters and to allow for difficult to quantify non-linear effects such as AM-PM conversion and perhaps terrestrial interference, a value of about 1dB should be sufficient. Some links may not balance if this parameter is set too high. If you are having trouble balancing a link budget, or getting negative excess margin warnings, set this value to zero.

虽然本程序按照工业标准计算雨衰并且包括在链路预算中，但是通常还是要留出一个整体的系统余量来应对各种输入的不确定性，以及各种难以计量的非线性效应如AM-PM调幅-调

相转换或者地面干扰，1dB就足够了。

如果这个量设的过高有些链路可能就会超出预算。如果你的链路预算超出预算，或者收到余量负溢出警告，请将该值设为0.

Edit Digital Modulation Method

编辑数字调制模式。

Select one of the three radio buttons to define the modulation scheme adopted and enter the value of M for an M-ary system. Example for 8-PSK you would enter 8. For QPSK (4-PSK) you would enter 4. Set M=2 for BPSK since it is a binary signaling system.

选择三个按钮中的一个来选择调制方案或者输入M值来选择一个M相键控系统。举例,8PSK 为8，QPSK为4，BPSK为2。

Edit Bit Error Rate

误比特率

The bit error rate (BER) is numerically equal to the bit error probability over the communication channel, and is quoted in 10 raised to the power n, where n is a negative integer. The equivalent of ITU-R grade 5 in analogue link budgets is BER = 10 ^ -6. That is to say there is likely to be one error in each million bits transmitted.

For convenience, only the logarithm to the base 10 need be input into this program's forms. For example with a BER of 10 ^ -6. you would enter -6. For a BER of 10 ^ -10 you would enter -10. This is used exclusively to calculate the Eb/No required without channel coding.

误比特率(BER)就是通信信道中每比特发生错误的概率，以10为底数n为指数，n是一个负整数。等效于ITU-R的5级模拟链接预算为BER=10^-6。这就是说平均1000000个比特里有一个会出错。

为了方便，只需要输入BER以10为底的对数即可。比如BER=10^-6只要输入-6，BER=10^-10输入-10.这个值用来唯一计算出所需要的信道Eb/N0。

Transponder Power Usage

转发器功率使用

The program checks if the transponder usage is either "power limited" or "bandwidth limited" at run time. If this box is checked and the transponder usage is detected as bandwidth limited, a power iteration is performed at the maximum supported carrier limit. This essentially underuses the available transponder power and often results in a lower uplink power. This is the default setting.

On the other hand, if the transponder usage is found to be bandwidth limited and this option is unchecked, no power iteration is performed and the link budget assumes all the available transponder power is to be used. The "Excess Margin" and consequently the resulting HPA capability could be significantly higher if this box is unchecked as there is less IBO per carrier. In a situation where large HPAs and small downlink antennas are required, as in TV broadcasting, this

option may be more appropriate.

In cases where the transponder is naturally power limited (common), this option has no effect and the budget is iterated for minimum uplink power requirements.

程序会检查转发器是“功率限定”还是“带宽限定”。如果这个选项被勾选并且转发器为带宽限定，功率计算将按照转发器支持最多的载波进行迭代计算，这实际上低估了转发器功率而且经常会导致较低的上行功率。这是默认设置。

另外如果转发器为带宽限定且这个选项未选，不会有功率叠加计算，假设所有的转发器功率都可用。当选项未勾选时，算出的HPA高功放功率可以显著增加，因为每个载波的IBO减少了。在大型上行天线和功放配合小型接收天线的情况下，比如TV广播，这种选项比较合适。

档转发器是自然功率限定的（普遍），这个选项没有作用，链路预算按照最小上行功率需求计算。

Downlink Optimization Radio Buttons

下行优化单选按钮

只有手动输入“载波数量”时才会在下行栏中出现，载波数量时“AUTO”时隐藏。它也在需要更大的系统余量使用。这个选项主要用于单载波转发器的使用，比如电视广播，需要把一切的余量留给下行链路，以减小接收天线的口径。

1）无：如果不需要下行链路优化（默认）、

2）天线口径：把链路设计的尽量减小下行接收天线的尺寸。算出的结果会输出到输入表格里的天线口径。如果迭代失败会显示一个警告，不过计算会继续。这个选项只计算最小可能的天线尺寸。有些情况下这不是唯一的选择。比如有时计算出的接收天线太小，边瓣就会收到相邻的卫星信号。如果发现天线大小不正常多数是因为输入了过高的下行信号可用度。99.5-99.9%就可以了。

3）可用度：用于使链路设计的可用度尽量高，而接收天线口径确定的情况。计算出的值直接输出到对话框中。如果迭代失败会显示一个警告，不过计算会继续。相似的，如果对于给定的天线大小，发现可用度小于95%—最低可用限度，在这种情况下请增加下行天线尺寸。

Calculate 计算

Using the Expression Evaluator

使用公式计算器

An expression evaluator is a convenient alternative to a calculator since you do not need to reenter keystrokes if you make a mistake. It is easy to edit the expression and try again. Click on the hot spots below for details on how to use it.

公式计算器是一个方便的计算器的替代品，因为你不用因为输错了而重新输入。它可以方便地更改表达式进行计算。点击下列链接以了解如何使用。

Entering the Expression

输入公式

The evaluator has one specific purpose, to evaluate a mathematical expression represented by a string of characters to a numerical result. Normal mathematical operators can be used as well as multi-level parenthesis. No equals sign or variable assignment is necessary and would be signaled as an error. White space is tolerated to aid readability..

计算器只有一个目的，就是把一段字符串表达形式的数学算式计算为一个数字的结果。普通的运算符合多极的括号都可以使用。不需要输入等号或者变量赋值，如果输入了会被判为出错。可以有空格来增加可读性。

Operator Precedence

运算顺序

- Negation 负号

* Multiply 乘

/ Divide 除

+ Add 加

- Subtract 减

^ Raise to the power 次方

All function arguments should be enclosed in parenthesis and trigonometrical functions may be user switched to either degree mode or radian mode. For example sin(45) or sin(pi/4) are equivalent depending on the mode selected Since most of us are more comfortable with degrees, this is the default mode. Function names may be entered in upper or lower case.

The supported functions working to double precision are as follows:

所有函数的参数都应该写在括号里，三角函数可以由用户切换角度和弧度模式。比如Sin（45）或者Sin（Pi/4）在两种模式中是一样的。我们都比较熟悉角度模式，所以它是默认值。函数名用大小写皆可。

下面是所有的函数，支持到双精度（浮点数）

abs calculates the absolute value of any number 绝对值

acos calculates the arc cosine of a value 反余弦函数

asin calculates the arc sin of a value 反正弦函数

atan calculates the arc tangent of a value 反正切函数

cos calculates the cosine of a value 余弦函数

cosh calculates the hyperbolic cosine of a value 双曲余弦函数

exp calculates the exponential e to the x (the argument) e的x次幂

log calculates the logarithm to the base 10 of a value 以10为底的对数

logt calculates the logarithm to the base 2 of a value 以2为底的对数

ln calculates the natural logarithm to the base e of a value 以e为底的对数

sin calculates the sine of a value 正弦函数

sinh calculates the hyperbolic sine of a value 双曲正弦

sqr calculates the square root of a value 平方根

tan calculates the tangent of a value 正切

tanh calculates the hyperbolic tangent of a value 双曲正切

Finally the constant 3.14159256 may be entered as the symbol pi or simply p.

最后，3.14159256可以用pi或者p代替。

Output Format

输出格式

The result is displayed truncated but correct to six decimal places. If the absolute value exceeds 1,000,000 or is less than 0.000001 the output defaults to an alternative exponent mode. For example -20,000,000,000 would be displayed as -20.000000e09 meaning 20*10^9. Note the e means exponent not exponential in this context. Another example, 0.000000003 would be displayed as 3.000000e-09 meaning 3*10^-9.

结果只保留小数点后6位。如果绝对值超过1000000或者少于0.000001，输出值会切换为指数模式。比如说-20,000,000,000会显示为-20.000000e09，表示20*10^9。注意e是代表指数计数，而不代表指数函数。另外一个例子0.000000003 显示为3.000000e-09 表示3*10^-9。

Mathematical Errors

The evaluator will try to detect common math errors, such as divide by zero, under flow and log / trig domain errors. However there may be some singularity, domain and overflow conditions which may be fatal causing the program to terminate with an appropriate message. In view of this possibility, it is recommended you save the current state of your work before using the evaluator with complicated expressions. This is less likely to happen, if at all, with the 32 bit version.

计算器会发现一般的数学错误，比如除数为0，浮点数下溢错误，对数函数超出定义域错误等。但是仍有一些特殊值、域和溢出条件可等会导致程序跳出错误信息并终止。基于此种可能，建议计算前保存现存的数据以防丢失。这种事很少发生，就算发生也只会出现在32位的版本上。

Degree Mode

角度模式

For trigonometrical functions, the expression evaluator may be set to work in degrees by selecting the degree mode radio button. The default setting is degree mode.

选择该模式后，三角函数中，算式表达的值为角度。默认设置为角度模式。