Victor Company of Japan, Limited

Nec Corporation

Fujio Suzuki

Nobuaki Takahashi

Takeshi Shibamoto

Koji Tanaka

Seiichi Takashima

Hiroyuki Sugiyama

Mitsuo Kubo

Mikiko Saito

Masao Kasuga

Mitsuru Kikuchi

Yoshiaki Amano

Hideo Sato

Yoshiki Iwasaki

Norio Shibata

Tsuneo Furuki

Katsuhiro Ohba

Kohji Tanaka

A magneto-resistive (MR) head having a read element including two magnetic shield films, two magnetic gap films which separate the two magnetic shield films and which are held between the two magnetic shield films, and an MR element held between the two magnetic gap films, with the two magnetic gap films having a stress value of up to 200 MPa.

Manufacturing process for a magneto-resistive head accommodating a narrow gap

Magneto-resistive head accommodating a narrow gap

An information signal recording medium has a spiral track on which an information signal is recorded. The information signal includes picture element data which correspond to one field, and is time-sequentially recorded on the spiral track in terms of the picture element data which correspond to one field. The picture element data which correspond to one field are made up of a plurality of picture element data of a first field and a plurality of picture element data of a second field, among picture element data which are obtained by subjecting an analog video signal to a digital pulse modulation, where the analog video signal corresponds to one frame made up of the first and second fields. A reproducing apparatus is designed to reproduce the second field in a sequence different from a sequence with which the recorded picture element data are reproduced from the information recording medium in the first field.

Information signal recording medium and reproducing apparatus therefor

A digital video signal reproducing apparatus comprises a reproducing circuit for reproducing a digital video signal from a recording medium, where the recording medium is time-sequentially recorded with the digital video signal having a signal format in which a header signal is added to each of divided picture element data groups which are obtained by dividing a picture element data group in terms of a predetermined unit, the picture element data group is obtained by subjecting an analog video signal to a digital pulse modulation at a sampling frequency such that a product of a number of picture element data in one scanning line and an effective number of scanning lines in one picture of a standard television system is exceedingly close to 2.sup.18 but less than 2.sup.18, and the header signal at least comprises a synchronizing signal and a picture mode identification code, a header signal reproducing circuit for discriminating the header signal within the digital video signal reproduced by the reproducing circuit and reproducing the header signal, two memory circuits into which the picture element data group within said reproduced digital video signal is written and from which a stored picture element data group is read out, a circuit for controlling write-in and read-out with respect to the two memory circuits according to a code in the reproduced header signal, and a circuit for producing an analog video signal in accordance with a standard television system from the picture element data read out from the two memory circuits.

Digital video signal reproducing apparatus

A digital video signal recording system and reproducing apparatus comprise a circuit for independently subjecting a luminance signal and two kinds of color difference signals of a color picture information to digital pulse modulation, to produce a digital luminance signal and two kinds of digital color difference signals, a circuit for dividing the digital luminance signal and the two kinds of digital color difference signals into picture element data groups, in terms of specific number of rows or columns which are adjacent on a screen, and adding a header signal at least comprising a synchronizing signal, a picture mode identification code, and a picture information quantity identification code to a beginning position of each of the divided picture element data groups comprising the digital luminance signal and the two kinds of digital color difference signals, to produce a digital video signal having a signal format in which the digital luminance, the two kinds of digital color difference signals, and the header signal are time-sequentially multiplexed, a circuit for recording the digital video signal onto a recording medium, a circuit for writing each of the divided picture element data groups picked up and reproduced from the recording medium into a memory circuit according to codes within the header signal, and a circuit for producing an analog video signal in accordance with a standard television system from picture element data read out from the memory circuit.

Digital video signal recording system and reproducing apparatus

A digital signal recording system and a reproducing apparatus for reproducing signals recorded according to this recording system comprise a circuit for alternately transmitting a first digital luminance signal and a first two kinds of digital color difference signals obtained by subjecting a color picture information signal to digital pulse modulation, in terms of information of one or a plurality of scanning lines, and producing a first digital video signal having a signal format wherein signal components of two sampling points of the first digital luminance signal are arranged within the same word and signal components of the same sampling point on a picture of the first two kinds of digital color difference signals are arranged within the same word; a circuit for time-sequentially multiplexing the first digital video signal and the digital audio signals obtained by subjecting audio information signal to be recorded to digital pulse modulation, in terms of words, and recording the time-sequentially multiplexed signal onto the same one track on a recording medium; a decoder for demodulating and reproducing analog audio signals from a signal picked up and reproduced from the recording medium; and a circuit for producing an analog video signal in accordance with a standard television system, from the output first digital video signal of the decoder.

Digital signal recording system and reproducing apparatus

Analog primary color video signals of a still-picture converted to luminance and color difference components and converted to digital samples. The digital samples of each video component are written into a respective memory at the sampling rate and retrieved by a reading circuit at a rate lower than the sampling rate. Analog multi-channel audio signals are converted to digital samples which are time-division multiplexed with the retrieved digital samples of the video components. The multiplexed digital samples are recorded on a recording disc medium in a spiral track pattern.

System for recording and reproducing time-division multiplexed digital

A multichannel record disc reproducing apparatus comprises a first phase locked loop circuit including a phase comparator and a voltage controlled oscillator for demodulating an angle-modulated wave signal. The modulated signal is separated from a composite signal picked up from a multichannel record disc on which a multiplexed direct wave signal and an angle-modulated wave signal are recorded. The output of the first phase locked loop is a demodulated signal. A second phase locked loop circuit includes a phase comparator and a voltage controlled oscillator, supplied with the separated angle-modulated wave signal and having a lock range of a width which covers and is wider than the maximum lock range width of the first phase locked loop circuit. A synchronous detector compares the phases of the angle-modulated wave signal and the output signal of voltage controlled oscillator of the second phase locked loop. The synchronous detector operates when the phase difference of the two signals deviates sufficiently from a predetermined phase difference. Means are provided for reducing or removing noise components which are developed in the demodulated signal in accordance with the output of the synchronous detector. This noise reduction or removal is provided in the first phase locked loop circuit and/or in a channel for transmitting the demodulated signal.

Multichannel record disc reproducing apparatus

A multichannel record disc reproducing apparatus has a pickup cartridge for picking up signals from a multichannel record disc. A multiplexed signal was recorded on the disc by first multiplexing direct wave signals and angle-modulated wave signals which are recorded on opposite groove walls. Filters separate the picked up multiplexed signal into the direct wave signal and the angle-modulated wave signal. A demodulates circuit for demodulating the angle-modulated wave signal, thus separated. A matrix circuit separates the signals to obtain a plurality of separate channels from the direct wave signals and the demodulated signals. A circuit in a stage preceding the demodulator removes substantially all components of the higher harmonics at the carrier wave center frequency, which carrier was used for angle-modulating the original signal.

Apparatus for reproducing a multichannel record disc

A multichannel record disc reproducing system comprises at least two phase-locked loops. Each loop includes a phase comparator and a voltage-controlled oscillator for respectively demodulating an angle-modulated signal which is separated from a signal picked up from a multichannel record disc. The picked up signal includes a direct-wave signal and an angle-modulated signal which were multiplexed and recorded. An addition circuit adds the demodulated output signals of the phase-locked loops. The respective phase-locked loops have different lock ranges in order to exclude noise and other distortion.

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Machida, Japan

Fujio Suzuki