METHOD FOR AUTOMATICALLY CONTROLLING THE AMPLITUDE OF INPUT SIGNALS

摘要

Input signals having the same functional time dependence, e.g. a sinusoidal one, and being out-of-phase with regard to each other are amplified selectively according to the result of a previous comparison of the amplitudes of a first and a second matched signals (s1m, s2m), which were formed from the input signals (s1, s2) by means of said selective amplifying, which step-by-step matches the output signals to each other in amplitude. There is measured the duration (T) of a time interval between such passings of the matched signals through a signal ground (gnd) that both matched signals have the same polarity in said time interval. It is ascertained on the basis of the time duration (T) that the frequency of the input signals is within preset frequency limits. The first matched signal is sampled the moment the second matched signal passed through the signal ground and the second one the moment the first one passed through the signal ground. Values obtained by sampling are compared to each other. A selective gain control signal is generated as a result of said comparison of the sample values. The gain applied to either input signal is increased or decreased. The method of the invention for automatically controlling the amplitude of input signals initiates an automatic selective amplification of individual input signals.