Amplitude modulated high frequency signal detection device

摘要

A high frequency signal detection device to be used in an information playback system for playing back signals from a record medium having a plurality of record tracks, includes first and second positive peak hold circuits having different time constant and a negative peak hold circuit. A difference circuit is provided to generate a difference signal between output signals of the first positive peak hold circuit and the negative peak hold circuit and an output signal of the difference circuit is compared with an output signal of the second positive peak hold circuit, to produce a high frequency signal detection signal. Thus, a very accurate detection signal is produced irrespective of the polarity of the input signal and whether or not the envelope of the high frequency signal is symmetric.