雙語暢銷書《艾倫圖靈傳》第7章:運轉起來(28)
The figure of 2000 Hz was in fact the one he intended to use, and his encipherment process would start with the speech signAl being sampled 4000 times a second.
The Delilah would then have to effect the addition of these sampled speech amplitudes to another stream of key amplitudes.
黛麗拉則把這些採樣的聲音振幅疊加到一組密鑰振幅上。The addition would be done in modular fashion, meaning that while speech sample amplitude of 0.256 units and key amplitude 0.567 units would be added to give 0.823 units, the addition of 0.768 and 0.845 would give 0.613, not 1.613.
這個疊加的過程就是模加，比如說0.256單位的聲音振幅和0.567單位的密鑰振幅疊加起來就是0.823單位，而0.768和0.845疊加就是0.613，而不是1.613。
The result of all this would be a train of sharp 'spikes', of heights varying between zero and one unit:
得到的結果是一組鋒利的脈衝，高度在0到1個單位之間注：The next problem was that of how to transmit the information of these 'spike' heights to the receiver.
接下來的問題是，如何把這些脈衝發送給接收者。In contrast to the X-system, Alan planned no quantisation of amplitudes here. He wanted to transmit them as directly as possible.
與X系統相比，艾倫的計劃中並沒有將振幅離散化，他想要儘量直接地發送它們。In principle the 'spikes' themselves could be transmitted, but being of such short duration, a few microseconds in fact, they would require a channel which could carry very high frequencies.
從理論上說，這些脈衝本身是可以發送的，但是它們的持續時間很短，實際上只有幾微秒，因此需要很高頻率的發送頻道。No telephone circuit could do this.
沒有哪個電話線路能夠做到這一點。To use a telephone channel the information of the 'spikes' would have to be encoded into an audio-frequency signal.
如果要使用電話頻道，脈衝信息就必須編碼成音頻信號。Alan's proposal was to feed each 'spike' into a specially devised electronic circuit with an 'orthogonal' property.
艾倫的想法是，把這些脈衝輸入一種特殊的正交電路，This meant that its response to a spike of unit amplitude would be a wave with unit height after one time interval, and with zero height at every other unit time interval:
一個單位振幅的脈衝，會反饋爲一段在1單位時間點上具有單位高度的波，而在其它單位時間點上的高度均爲0：
