| 摘要 |
PURPOSE:To eliminate residual amplitude deviation by setting <=5 frequencies for a signal for amplitude equalization, and providing a variable resonance type equalizing circuit with one more primary gradient equalizing circuit. CONSTITUTION:An input signal is supplied to a variable resonance type equalizing circuit 1, whose output is supplied to five filters 11-15 for extracting five different frequencies in a transmission band. Their outputs are inputted to a control circuit 10 through detectors 16-20. According to level relation among the input signals, the control circuit 10 controls the resonance freuqnency and sharpness of the variable resonation type equalizing circuit 1 to obtain simple residual primary gradient deviation without allowing residual amplitude characteristics to vary. Then, signal levels extracted by filters 24 and 25 are equalized to each other by a trailing loop B, eliminating the amplitude deviation completely. |
