双语畅销书《艾伦图灵传》第6章:连接两个世界(9)
They had begun in 1941 with the Vocoder, and tried to adapt it to their purpose by approximating its eleven outputs as being either 'on' or 'off'.
This, however, resulted in a 'badly mutilated' speech signal.
但是这样产生的语音信号是严重残缺的，无法使用。Accordingly they had abandoned the simple binary 'on or off of the Vernam cipher, and instead approximated the Vocoder outputs not by two possible levels, but by six.
于是，他们放弃了简单的二进制形式，转而采用六进制来对声码器的输出进行编码。
The effect was to encode the speech-signal as a total of twelve streams of 'base six' digits, like 041435243021353....
其效果就是把语音信号编成12串六进制数，比如041435243021353……Each such stream would then be added in modular fashion to a similar but random key sequence, and the result transmitted.
这样的，然后给它模加注上一串形式相似、但却是随机的密钥，最后再进行传送。At the other end the identical key would be subtracted, and the speech reconstituted.
接收端收到信号后，减掉一组同样的密钥，就可以重新得到语音。The speech signal was to be sampled for its 'levels' fifty times a second, which meant that the transmission was roughly equivalent to sending 300 teleprinter characters a second.
语音信号每秒要采样50次，这意味着每秒要发送300个字符。They had succeeded in devising the equivalent of a one-time pad system for speech.
他们成功地为这套语音系统设计了一次性密钥手册注。The development was given the intriguing name of 'Project X' or the 'X-system'.
这项新发明，被赋予了一个非常激动人心的名字：X系统。By November 1942 an experimental model had been installed at New York and tested with5 'a synthetic set of signals from a signal generator that had previously been sent to England'.
1942年11月，一台实验样机在纽约部署完毕，并用之前送到英国的信号发生器来产生信号进行测试。In January 1943 they were beginning to assemble the first model intended for operational use.
1943年1月，他们开始装配第一台军用样机。
