PAM to PCM code converter for PCM communications - varies conversion curves of coder and decoder relative to one another to reduce distortion

摘要

The PAM to PCM code converter (and vice versa), for a PCM communications system, consists of a coder at the transmitter and a decoder at the receiver. The relative positions of the conversion curves of the coder and decoder are altered relative to the instantaneous amplitude of the PAM signal such that the baseline voltage obtained by dividing the supply voltage is varied by a voltage divider. - The divided voltage depends on the frequency of occurrence of higher-valued binary bits in the retrieved or received PCM words. The higher-valued bits are integrated by an RC circuit coupled to the controllable part of the voltage divider. The baseline voltage is taken from the capacitor.