| 摘要 |
1,113,700. Analogue-to-digital converters. STANDARD TELEPHONES & CABLES Ltd. 22 Nov. 1966, No. 52125/66. Heading G4H. In an encoder for converting analogue signals into a symmetrical binary code, the zero level of the input signal is adjusted to lie in the centre of the code range by a feed-back between the digit output and the input, having means for examining the polarity of each of the successive channel codes, means assigning a polarity to a block of channel codes, means for generating a corresponding analogue bias signal which is applied to the input to equalize the number of channels having opposite polarities. The digital outputs are each preceded by a polarity signal which are gated by gate 10 to a counter 9 the output of which indicates whether the majority in a group of channel codes is positive or negative. Flip-flop 6 is set in one state or the other and integrator RC to a bias signal generator 8 to apply a signal to the input at 3. The whole block of channels may be divided into m groups of n channel codes, each n channel codes being examined as before to see whether the majority is positive or negative and the outputs are applied to a further counter indicating whether the majority of the n groups has a positive or negative preponderance. The counter adapted to indicate whether the majority of n polarity signals is positive or negative has a capacity of ¢ (n + 1), n being odd. The capacity will be exceeded or not to give the required indication. |
