Abstract: A video signal recording and reproducing apparatus comprises a circuit for generating a first signal having a sampling frequency f.sub.s which is approximately a natural number multiple of a horizontal scanning frequency f.sub.H of an input composite video signal and satisfies f.sub.s .apprxeq.f.sub.L +f.sub.U and having a phase which differs by 180.degree. for every one field, where f.sub.L represents a constant frequency in the range of 0.5 to 1 MHz and f.sub.

Abstract: A signal-to-noise ratio improving circuit for a color video signal comprises an adder supplied with a chrominance signal of an input color video signal, a delay circuit supplied with an output signal of the adder, for delaying the signal supplied thereto by a delay period which is in terms of one horizontal scanning period of the input color video signal and producing an output signal to the adder wherein the output signal of the delay circuit is added with the input chrominance signal, and a switching circuit supplied with the input chrominance signal and the output signal of the adder. The switching circuit passes the output signal of the adder during an interval corresponding to a color burst signal of the input chrominance signal and passes the input chrominance signal during intervals other than the color burst signal interval of the input chrominance signal.

Abstract: A video memory device comprises an analog memory part in which memory elements are arranged in a matrix form with a plurality of rows and a plurality of columns, for storing an input analog video signal, an input circuit for applying the input analog video signal to the analog memory part and causing the analog memory part to store the input analog video signal, and an output circuit for obtaining an analog video signal delayed by a predetermined delay time from the analog memory part.

Abstract: A system for controlling the rotation of a rotating structure comprises a detector for detecting the rotation of the rotating structure a circuit for repeatedly forming address signals for every revolution of the rotating structure in response to a detection output from the rotation detector, a memory circuit in which control data responsive to deviations in the rotational peripheral speed of the rotating structure in each revolution thereof have been stored beforehand at addresses corresponding to the address signals, the address signals being supplied to the memory circuit, whereupon the data stored at the corresponding addresses are read out, and a control circuit for obtaining a control signal from the detection output of the rotation detector and the data thus read out from the memory circuit and accordingly controlling the rotation of the rotating structure.

Abstract: A system for controlling the rotation of a direct current motor has an armature resistance control circuit. An operational amplifier has one input terminal connected to the direct current motor and another input terminal connected to form a differential amplifier. A first resistor is connected between an output terminal of the operational amplifier and one of the input terminals. A second resistor is connected between the other input terminal of the operational amplifier and a terminal for applying a control signal voltage thereto. A third resistor is connected between the output terminal of the operational amplifier and the other input terminal. The rotational phase of a structure rotated by the direct current motor produces a phase detection signal. A phase comparing means compares the phase detection signal with a reference signal and applies the resulting output, phase comparison error signal as a control signal voltage.

Abstract: A color video signal recording system comprises a frequency modulator. A luminance signal is separated from an input color video signal. The amplitude of a color burst signal is intensified after it is separated from the input color video signal. The intensification is with respect to the amplitude of a carrier chrominance signal separated from the input color video signal. An automatic chroma control circuit receives the intensified color burst signal and the non-intensified carrier chrominance signal to effect level control. A specific level is not exceeded. A first frequency converter converts the frequency of the output signal of the automatic chroma control circuit. The converted signal is in a band which is lower than the band of said frequency-modulated luminance signal. The frequency-modulated luminance signal and the resulting output signal of said first frequency converter are mixed and multiplexed. A transducing head records the resulting mixed and multiplexed signal on a recording medium.