PSK31 Mode [复制链接]

psk31 is a new amateur radio teletype mode invented by amateur radio enthusiasts like peter martinez g3plx. like traditional rtty, it is a kind of keyboard to keyboard communication (chat). the baudrate used is 31.25 baud, fast enough to handle most operators manual typing capabilities. it is not suitable for transporting computer data like pictures or programs, but intended as a mean of human communication between two or more operators in a very simple and thus very robust way. it can be compared to cw (morse code radio communication), but it is more efficient than cw. it uses a bandwith of just 31 hz with a speed of about 288 lpm or 48 wpm (words per minute). according to the small bandwidth, the system gain against a cw filter with 500 hz is 12 db. that means a cw transmitter has to output 16 times more power than a psk31 transmitter to gain the same signal to noise ratio on the receiving side. psk31 seems to be the perfect mode for all amateur radio stations with small antennas and little power.

as the name of the new mode says, psk (phase shift keying) modulates the carrier phase. the phase modulation has some more advantages against cw, which uses ask (amplitude shift keying). in noisy and distorted propagation environements, the amplitude of a signal varies much more than the phase of a signal. to cope with the problem of phase shifts caused by different propagation paths (especially in hf links), the modulation is done in differential phase shift keying (dpsk). thus only the phase differences between two bits are used, not the absolute phase.

to get some kind of online information compression (like zipping files on the computer), g3plx introduced the use of a varying length code (varicode). in contrast to normal compression techniques where statistical analysis is used during transmission, g3plx does something samual morse did many years ago. he analyzed english language ascii textfiles and built an alphabet, where the more frequently used characters are represented by less lengthy codewords. additionally he made the code selfsynchronizing, which means there are no codewords having two or more zero bits in them. two zero bits are used to describe the end of a word. thus eliminating the start and stop bits used in asynchronous codes like the ascii or baudot code.

the plan for psk31 activity has always been (since psk31 started) to concentrate activity starting from the bottom edge of the iaru rtty band plan, expanding upwards as activity increased. the exception is in the 10m band in order to give non full privileges ham to meet. it was defined as 150 hz above it. keep in mind that all you need is about 100 hz as channel separation. these recommended frequencies are in accordance with the iaru band plan for region 1: 160m (1838 khz), 80m (3580 khz), 40m (7035 khz), 30m (10142 khz), 20m (14070 khz), 17m (18100 khz), 15m (21080 khz), 12m (24920 khz) and 10m (28120 khz). however, most psk31 activity can be found +/- 5…10 khz around these frequencies.

下面是google翻译的：
psk31业余无线电电传方式是一种新发明的业余无线电爱好者喜欢彼得g3plx内斯. rtty喜欢传统,它是一种沟通键盘键盘(聊天). 用的是31.25波特速率,足以应付最为快速打字手工操作能力. 它并不适合计算机数据传输照片或喜欢的节目,但作为一种人类沟通指两个或两个以上的经营很简单,因而十分强劲. 这就好比化学(无线电通讯莫尔斯码),但它比化学更有效. 它是用带宽31赫兹刚刚以288左右的速度山泥倾泻或以wpm48(每字分钟). 据小带宽,该系统针对连续滤波器增益12分贝,500赫兹. 这意味着已连续发射机输出功率超过16倍,取得了同样的发射机psk31信噪比就接收方. psk31方式似乎是所有业余电台完美小天线和实权.

作为新模式的名字说,库尔德斯坦(相位键控)调制载波相位. 调相有更多的优势连续打击,以问(振幅键控). 在喧嚣和歪曲繁殖environements,振幅不同的信号比阶段的信号. 为了应付不同所造成的问题逐步转向传播途径(尤其在短波通)调制做差相键控(的dpsk). 因此相区别只用两个比特,而不是绝对的阶段.

取得某些网上信息压缩(如压缩计算机档案)g3plx推出使用不同长度码(varicode). 相对于正常使用压缩技术统计分析,在那里输电、g3plx做点事samual摩士多年前. 他分析了建一个英文字母和代码textfiles,更常用的字码是由少长篇. 此外他还selfsynchronizing代码,即有两个或两个以上具有无码零零碎入. 两零比特来描述末一句话. 因而开始停止使用的异步比特码如代码或代码baudot教授.

psk31活动计划一直(以来psk31开始)集中活动从底部边缘iarurtty的乐队计划,拓展活动内容向上增加. 唯一的例外是在乐队26,472,627.49为了让火腿不完全符合的特权. 它定义为150赫兹以上. 记住,只需约100赫兹作为渠道分离. 这些建议按照频率波段iaru规划区内1:160m的(1838千赫)80m(580千赫),111(035千赫)、三十米(142.0千赫),600(14070千赫),17m条(18100千赫)2,252,451.70(21080千赫)二型(24920千赫)26,472,627.49(28120千赫). 不过,可以找到活动最psk31+/-510千赫左右::这些频率.

psk31模式
　　psk31是一种新的业余无线电电传通讯模式，它由g3plx-皮特·马蒂尼（peter martinez）这样狂热的业余无线电爱好者所发明。和传统的rtty模式一样，它是一种键盘对键盘的通讯方式（聊天对话）。它使用的符码率是31.25波特，对于应付大多数操作者的手工打字能力来说，已经是足够快了。它并不适合于传输计算机数据，例如图像或者程序，但可以作为架设在两个或者多个操作者之间的一种非常简单而稳健的人际交流手段。它可以与cw（无线莫尔斯电报通讯）相媲美，但它比cw要更有效率。它仅仅使用31hz的带宽就可以提供大约288lpm或48wpm（每分钟单词数）的传送速度。得益于很小的带宽，相对于一个500hz带宽的cw滤波器来说，可以多获得12db的系统增益。这意味着一台cw发信机需要输出16倍于一台psk31发信机的功率来提高接收端的信噪比。psk31似乎是所有使用小天线和低功率的业余无线电台操作模式的完美选择。
　　正如这种新操作模式的名字所指的，psk（相移键控）调制载波的相位。相位调制与使用ask（幅度键控）的cw相比有很多优点。在嘈杂和扭曲失真的传播环境里，一个信号的振幅比它的相位更容易变化。为了克服由多径传播造成的相移失真难题（特别是在hf链路里），调制采用差分相移键控（dpsk）来完成。这样只使用两个比特之间的相位差，而不是绝对相位（来判决信号）。
　　为了达到对在线传送的信息进行压缩的目的（就像计算机中使用的zip文件那样），g3plx引入了一种变长码的使用（varicode）。对比于通常的在发信过程中进行统计分析的压缩技术，g3plx做了莫尔斯（samual morse）在很多年前做过的事。它分析了诸多英语ascii文本文件并建立起一个字母表，在这个表中，越频繁使用的字母将被赋予更短的码字。除此之外，他还建立起编码自同步机制，也就是说表中没有使用2个或更多0比特位的码字。两个0比特被用来表示单词的结尾。这样可以消除类似ascii或baudot这样的异步码中的起始和停止位。

　　最后一段我译不出……汗'

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