Matsushita Electric Industrial Co., Ltd.

Kozo Kurashina

Kunio Sekimoto

Chojuro Yamamitsu

Katsuhiko Yamamoto

A portable video tape recorder for broadcasting applications comprises a pair of video heads mounted diametrically opposite to each other on the circumference of a rotary cylinder. High and low frequency carriers are modulated by frequency modulators with I and Q signals, respectively, and frequency division multiplexed for application to the video heads. The frequency values of the carriers are selected so that third-order distortion noise caused by the hysteresis characteristics of the video heads and the magnetic tape may fall within a frequency range differing from the frequencies of the modulated carriers by an amount greater than the bandwidth of the I and Q signals which are demodulated by frequency demodulators to prevent the occurrence of beat interference in the frequency band of the reproduced video signal.

Video tape recorder immune to third-order distortion noise

In a video tape recorder, luminance and chrominance signals are recorded respectively by first and second transducer heads along separate tracks skewed to the direction of tape motion. The transducer heads are rotated during particular modes such as slow-motion or still picture reproduction, in a tape-head speed relationship different from the normal tape-head speed relationship, causing the transducer heads to traverse several tracks. A switching circuit is coupled to the transducer heads to selectively connect the outputs of the heads to an output circuit in response to a point of transition of amplitude of the output signal from the second head to cancel unwanted signal components detected by the heads during traversal across the tracks.

Video tape recorder with inter-channel switching circuit for special

Luminance and chrominance signals, which are interleaved with respective synchronization signals, are recorded through the use of two video transducer heads alternately in skewed separate tracks of a recording tape. Upon reproduction, the timing signals are separated from the luminance and chrominance signals and compared in phase between them to detect the phase difference between the luminance and chrominance signals. A variable delay line is provided to introduce a variable delay interval as a function of the detected phase difference to the one of the signals which is advanced in phase relative to the other. The time axis deviation of the video signal from a standard phase is also detected by a comparison between the time base, or horizontal sync pulse, and a reference time base to introduce a delay time to both the luminance and chrominance signals.

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Yahata, Japan

Kozo Kurashina