Abstract: An improved monaural signal judgement circuit which is capable of judging whether or not an input signal is monaural when signals from a television, a video cassette tape recorder, an audio cassette tape recorder, a compact disc player, or the like are inputted to the monaural signal judgement circuit and of converting the process into a pseudo stereo function when the input signal is monaural, which includes a wave form shaping circuit for separately wave-form-shaping a left-side signal and a right-side signal inputted thereto; an operation circuit for computing a signal level difference of the wave-form-shaped right-side and left-side signals; a control signal setting circuit for setting a control signal in accordance with an output of the operation circuit; an input control circuit connected between an input side of the operation circuit and an output side of the control signal setting circuit for adjusting a signal level at an input side of the operation circuit in accordance with a control signal applied

Abstract: A compact disk playback/recording system having a compact disk playback apparatus and a cassette recording apparatus.

Abstract: A faulty operation prevention circuit for an infrared-ray remote controller comprising inverter for inverting a transmission signal from the infrared-ray remote controller, a first pulse generation circuit for generating pulses in response to an output signal from the inverter, each of the pulses having a first width, a noise identification unit for identifying an optical noise contained in the transmission signal from the infrared-ray remote controller in response to the output signal from the inverter and the output pulses from the first pulse generation circuit, the noise identification unit having first and second transistors, and a second pulse generation circuit for generating a pulse in response to an output signal from the noise identification unit, the pulse having a second width.