Samsung Electronics Co., Ltd.

Chun-Sub Kim

Yong-Serk Kim

A playback/recording modulating-demodulating device, having a voltage-controlled oscillator (VCO), a voltage-current inverter (VCI), a band-pass filter, an amplitude limiter, and a phase-locked loop. In playback mode, the playback input signal is applied to the band-pass filter, the phase-locked loop is activated, and the VCI is set to produce a reference signal which controls the band-pass filter to tune the playback input signal. The tuned playback signal is applied to the amplitude limiter which produces an amplitude-limited signal which is applied to the phase-locked loop to produce a demodulated playback output signal. In record mode, the phase-locked loop is deactivated, the VCO produces a signal having a frequency which varies according to the voltage of a record input signal, and the VCI outputs a current control signal, having an output current related to the voltage of the record input signal, which is applied to the band-pass filter to control its bandwidth. A signal having a frequency value determined by the voltage of the record input signal is output by the VCO and applied to the band-pass filter, which outputs a record output signal. Thus, in the record mode, the bandwidth of the band-pass filter is related to the frequency of the signal which it filters.

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Suwon, South Korea

Chun-Sub Kim