| 摘要 |
PURPOSE:To obtain an adaptive type delta modulation coder/decoder in following to the sudden change in an analog input and having a small quantized noise by forecasting and controlling the optimum step width of integration depending on the signal being the exponentinal smoothing of a past coding string. CONSTITUTION:The output of a flip-flop 7 is multiplied by (1-alpha) by an attenuator 12 and the result is fed to an adder 13. A sample holding circuit 14 holds the output of the adder 13 by one clock and an attenuator 15 multiplies it by alphaand the result is fed to the adder 13. Thus, the output of the adder 13 is subjected to the exponential smooting to the output of the flip-flop 7. When H levels are consecutive at the output of the flip-flop 7, the voltage approaches the H level and when L levels are consecutive, the voltage aproaches the L level, then a current proportional to the difference between the center voltage and the H or L level is formed by a V-1 converter 10 and given to an integration device 11, then the current is increased when the analog input change is frequent and H or L levels are consecutive, the gradient of an analog feedback signal is high and the signal follows the analog input.
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