| 摘要 |
Corruption in digital data communications systems is detected, at the receiving end, by taking a number of samples of the received signal within each bit period. Flip flops (4, 7 and 8) are used to take samples from the digitised received signal as follows: flip flop (4), a mid bit sample indicative of the value of the centre of the bit; flip flop (7), a pre-mid sample taken within the bit period before the mid-bit sample; and flip flop (8), a post-mid sample taken within the bit period after the mid-bit sample. Gating circuitry (23, 24, 25) is used to analyse the three samples and give a "good" or "bad" output signal to register 11 as a result of the analysis. Corruption is judged to be present if any one of the samples has a different value to the others.
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