【正文】 transport package length, or payload, in bytes.The RS code can vary according to the system for example,DVBS = 204/188Hughes DSS = 146/130IBS = 126/112Reed 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.輸入里德所羅門外部碼（n/k）。這個(gè)數(shù)字可以以分?jǐn)?shù)輸入，比如204/188，程序會(huì)自動(dòng)在運(yùn)行時(shí)計(jì)算?；蛘吣阋部梢暂斎胍粋€(gè)小數(shù)，比如相應(yīng)（204/188）。前者一般是比較簡(jiǎn)單的方式。分子n，為受保護(hù)的包長(zhǎng)字節(jié)。分母k，為傳輸?shù)陌L(zhǎng)，或者說(shuō)負(fù)載，以字節(jié)計(jì)。不同的系統(tǒng)ＲＳ碼率不同。比如DVBS = 204/188Hughes DSS = 146/130IBS = 126/112ＲＳ碼用來(lái)糾正突發(fā)的傳輸錯(cuò)誤。它經(jīng)常以如下方式表示：RS[204,188, t=8]當(dāng)ｎ＝２０４，ｋ＝１８８．?dāng)?shù)值ｔ＝８只表示這個(gè)編碼每個(gè)包可以糾正８字節(jié)，和我們的計(jì)算不相干。1+Rolloff factor1+滾降系數(shù) 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 to are frequently used here. If in doubt, enter a nominal value of .Note: The bandwidth used by a digital carrier is proportional to the symbol rate, not the bit rate.數(shù)字濾波器的滾降系數(shù)通常表示為一個(gè)圖形。但是實(shí)際使用中計(jì)算擴(kuò)展的帶寬為（１＋滾降系數(shù)）。如果不清楚。數(shù)字載波的帶寬和它的符號(hào)率成正比，不是比特率。Carrier Spacing Factor載波分隔系數(shù)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 carrier39。s centre frequency.A typical value to enter is for multicarriers sharing the same transponder. If you do not require any carrier spacing, enter the same value as you entered for (1+ rolloff 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.共用轉(zhuǎn)發(fā)器時(shí)，分配的帶寬一般比載波所占的帶寬要大。這是用來(lái)減小相鄰載波的干擾并允許載波中心頻率小幅度的偏移。，輸入值設(shè)為“1+滾降系數(shù)”的值。不能設(shè)小于“1+滾降系數(shù)”的值，因?yàn)閮蓚€(gè)值會(huì)影響最終的符號(hào)率。注意，有的程序中這些值會(huì)影響占用帶寬而非符號(hào)率。Bandwidth Allocation Step Size帶寬分配塊大小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 . If you do not require this rounding up process then just enter zero.天線運(yùn)營(yíng)商有時(shí)將頻帶分成固定帶寬的塊進(jìn)行過(guò)按塊收費(fèi)。計(jì)算轉(zhuǎn)發(fā)器租用帶寬數(shù)量時(shí)，非配的帶寬通常向上取整于最近的分配快。比如說(shuō)，典型的帶寬分配塊大小為100kHz。如果你不需要向上取整過(guò)程只要輸入0.System Margin系統(tǒng)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 nonlinear effects such as AMPM 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.雖然本程序按照工業(yè)標(biāo)準(zhǔn)計(jì)算雨衰并且包括在鏈路預(yù)算中，但是通常還是要留出一個(gè)整體的系統(tǒng)余量來(lái)應(yīng)對(duì)各種輸入的不確定性，以及各種難以計(jì)量的非線性效應(yīng)如 AMPM調(diào)幅調(diào)相轉(zhuǎn)換或者地面干擾，1dB就足夠了。如果這個(gè)量設(shè)的過(guò)高有些鏈路可能就會(huì)超出預(yù)算。如果你的鏈路預(yù)算超出預(yù)算，或者收到余量負(fù)溢出警告，請(qǐng)將該值設(shè)為0.Edit Digital Modulation Method編輯數(shù)字調(diào)制模式。Select one of the three radio buttons to define the modulation scheme adopted and enter the value of M for an Mary system. Example for 8PSK you would enter 8. For QPSK (4PSK) you would enter 4. Set M=2 for BPSK since it is a binary signaling system.選擇三個(gè)按鈕中的一個(gè)來(lái)選擇調(diào)制方案或者輸入M值來(lái)選擇一個(gè)M相鍵控系統(tǒng)。舉例,8PSK為8，QPSK為4，BPSK為2。Edit Bit Error Rate誤比特率The bit error rate (BER) is numerically equal to the bit error probability over the munication channel, and is quoted in 10 raised to the power n, where n is a negative integer. The equivalent of ITUR 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 program39。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.誤比特率(BER)就是通信信道中每比特發(fā)生錯(cuò)誤的概率，以10為底數(shù)n為指數(shù)，n是一個(gè)負(fù)整數(shù)。等效于ITUR的5級(jí)模擬鏈接預(yù)算為BER=10^6。這就是說(shuō)平均1000000個(gè)比特里有一個(gè)會(huì)出錯(cuò)。為了方便，只需要輸入BER以10為底的對(duì)數(shù)即可。比如BER=10^6只要輸入6，BER=10^。Transponder Power Usage轉(zhuǎn)發(fā)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 (mon), this option has no effect and the budget is iterated for minimum uplink power requirements.程序會(huì)檢查轉(zhuǎn)發(fā)器是“功率限定”還是“帶寬限定”。如果這個(gè)選項(xiàng)被勾選并且轉(zhuǎn)發(fā)器為帶寬限定，功率計(jì)算將按照轉(zhuǎn)發(fā)器支持最多的載波進(jìn)行迭代計(jì)算，這實(shí)際上低估了轉(zhuǎn)發(fā)器功率而且經(jīng)常會(huì)導(dǎo)致較低的上行功率。這是默認(rèn)設(shè)置。另外如果轉(zhuǎn)發(fā)器為帶寬限定且這個(gè)選項(xiàng)未選，不會(huì)有功率疊加計(jì)算，假設(shè)所有的轉(zhuǎn)發(fā)器功率都可用。當(dāng)選項(xiàng)未勾選時(shí)，算出的HPA高功放功率可以顯著增加，因?yàn)槊總€(gè)載波的IBO減少了。在大型上行天線和功放配合小型接收天線的情況下，比如TV廣播，這種選項(xiàng)比較合適。檔轉(zhuǎn)發(fā)器是自然功率限定的（普遍），這個(gè)選項(xiàng)沒(méi)有作用，鏈路預(yù)算按照最小上行功率需求計(jì)算。Downlink Optimization Radio Buttons下行優(yōu)化單選按鈕只有手動(dòng)輸入“載波數(shù)