A correlator employing Hall multipliers applied to the analysis of vocoder control signals

After an initial discussion of short-term correlation functions the design and performance of an auto-and cross-correlator using Halleffect multipliers are described. It is shown that these devices are well suited to act as the multiplying elements and as modulators in associated circuits, provided that one of the time functions to be multiplied has a narrow bandwidth. Examples of measured auto-and crosscorrelation functions are given for sine waves and noise and for the control signals of a vocoder, from which interesting conclusions can be drawn about the redundancy of vocoder signals.