| 摘要 |
PURPOSE:To equalize the amplitude of an input signal which has the amplitude distorted nearly to characteristics opposite to those of a variable resonance circuit which is variable in center frequency omega0 and frequency selectivity Q0 by increasing or decreasing the center frequency omega0 of the variable resonance circuit according to a value P1-P3 which is obtained by subtracting the output level P3 of a narrow band-pass filter from the output level P1 of another narrow band-pass filter, and increasing or decreasing the frequency selectivity Q0 according to the difference between an interpolated value P2 calculated from the gradient between P1 and P3 and an actual value P2. CONSTITUTION:A microcomputer 1096 detects three pilot levels in a variable resonator output through analog-digital converters 1190, 1191, and 1192, and varies control signals SW0 and SQ for controlling theta0 and Q0. Further, automatic gain control for controlling a center pilot level P2 to a constant value so as to hold the mean level of the whole constant is performed to vary a control signal Sh for varying a passing gain H0, and SW0, SQ, and Sh are converted by digital-analog converters 1193, 1194, and 1195 into analog signals, which are supplied to the variable resonator. Consequently, the signal having the amplitude distorted which is inputted from an input terminal 600 is amplitude-equalized and outputted to an output terminal 601. |
