摘要 |
A periodic input signal Sa is input into a first subtracter and is input on the other hand into a second subtracter, a difference signal Sb between the periodic input signal Sa and a signal Se obtained by delaying this signal by 1H is obtained in a second subtracter. This difference signal Sb is input into a first limiter amplifier having a specific gain factor and a second limiter amplifier having a smaller gain factor, the outputs of the first and second limiter amplifiers are input into a third subtracter. A signal Sc is obtained by subtracting the output of the second limiter amplifier from the output of the first limiter amplifier. This signal Sc is subtracted from the input signal Sa by the first subtracter to obtain a filter output Sd. Thereby, without using a non-correlation controlling switch, a tailing phenomenon by a large variation of a signal amplitude can be reduced most suitably, a noise suppressing operation is made in a minute signal, a tailing is suppressed in response to the signal variation amount in a medium signal and further, tailing can be substantially eliminated in a large amplitude signal.
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