Matsushita Electric Industrial Co., Ltd.

Masao Tomita

Masahiro Honjo

Akio Hashima

Masaaki Kobayashi

Haruo Ohta

Tokikazu Matsumoto

Yukio Nakagawa

Mineo Mino

Kiyoji Fujisawa

Takenobu Isaka

Akihiro Takeuchi

Atsuo Ochi

Kazuhiro Yamanishi

Sakon Nagasaki

Masayuki Matsumoto

Tadaaki Matsuo

Takuya Otsuki

A video tape recorder is provided which is capable of handling plural television standards. The tape recorder includes a video signal processing unit for recording and reproducing video signals selectively in plural television standards, a television standards converter for performing a conversion operation by converting a video signal in a first one of the television standards into a video signal of a second one of the television standards, and a convert control unit for controlling the conversion operation of the television standards converter to operate in (1) a recording mode to convert an input video signal in a first one of the television standards into a second one of the television standards and to provide the converted input video signal to the processing unit for recording and (2) a reproducing mode to convert a reproduced video signal, received from the processing unit, in a first one of the television standards into a second one of the television standards and to output the converted reproduced video signal.

Video taperecorder with television standards converter

A video tape recorder in which video and audio signals of a plurality of channels are simultaneously recorded onto the same tape by using the same tape running mechanism and the signals of a plurality of channels may be simultaneously reproduced from the tape. The video tape recorder of the invention comprises a recording system and a playback system. The recording system includes a recording processing unit for converting the plurality of video signals into recordable signals, respectively; first and second rotary head pairs which are oppositely arranged with respect to a cylinder. Each head has a track width narrower than a recording track pitch and have gap azimuth angles in an opposite relation. Each head records the signals onto the tape and reads out the signals from the tape. The recording system further includes a unit for recording a control signal synchronous with a vertical sync signal included in one video signal onto a control track. The playback system includes a playback processing unit for reconstructing reproduced signals from the rotary head pairs into video signals and a servo unit for reproducing the control signal to control the rotary head pair and the tape run.

Video tape for recording and reproducing plural different independent

A video signal processing apparatus includes a digital vertical filter for passing a signal in a specific vertical high frequency band of a digitized input luminance signal and a digital nonlinear processing circuit having a nonlinear input-output characteristic for nonlinearly processing the signal from the vertical filter so that one of a luminance signal component and a noise component of the signal from the vertical filter is suppressed while the other is maintained as is or so that the luminance signal component is emphasized while the noise component is maintained as is or suppressed. The apparatus also includes an arithmetic operation circuit for arithmetically synthesizing the digitized input luminance signal and an output signal of the nonlinear processing circuit so that the noise component is canceled or the luminance signal is increased, thereby obtaining a digitized luminance signal having an improved signal-to-noise ratio in the specific vertical high frequency band.

Video signal processing apparatus for removing noise from reproduced

A low-range-converted chrominance signal is demodulated into two color difference signals. The two color difference signals are each filtered by a comb filter to eliminate undesired components. The two color difference signals, having been filtered, are modulated to obtain a carrier chrominance signal having a prescribed carrier frequency. To be suitable for digital signal processing, the low-range-converted chrominance signal is sampled at a first frequency which is an integral multiple of a low-range-converted carrier frequency of the low-range-converted chrominance signal when being demodulated. The two color difference signals are sampled at a second frequency which is an integral multiple of the prescribed carrier frequency of the carrier chrominance signal.

Method of reproducing a chrominance signal from a previously

A chrominance signal processing apparatus for converting an input carrier chrominance signal received in a first operation mode to an output low-band converted chrominal signal, and for converting an input low-band converted chrominance signal received in a second operation mode to an output carrier chrominance signal includes a frequency converting circuit which performs these conversions in the respective first and second operation modes. A carrier chrominance signal carrier and a low-band converted chrominance signal carrier, both for use in the frequency converting circuit, are respectively generated by the first and second carrier generating circuits. In each of the first and second operation modes, one of the first and second carrier generating circuits is controlled to compensate for a phase error of each of the input signals. A phase error detecting circuit detects the phase error from the burst signals extracted from the output and respectively input low-band converted chrominance signals in the first and second operation modes to produce a control voltage signal for controlling the first or second carrier generating circuit. Control signals for the ACC and color killer circuit are also produced from the abovenoted burst signals.

Chrominance signal processing apparatus

A video signal processing apparatus used for a video tape recorder performs chrominance signal processing which is digitalized. The chrominance signal is up-converted and phase-shifted in a recording block, and, in a reproducing block, phase-shifted in the opposite direction, filtered by a comb filter, compensated for jitter, and up-converted to the original chrominance signal. Both the recording block and the reproducing block are digitalized or only the reproducing block is digitalized. The digital chrominance signal processing circuit includes an A/D converter, a digital phase shifter, a digital comb filter, a digital jitter compensator, and a D/A converter.

Video signal processing apparatus for video tape recorders

A dropout compensating apparatus used in a video signal recording/reproducing apparatus employs a digital delay circuit such as a digital memory. An input video signal is converted to a digital signal by an A/D converter. The digital signal is applied via a first switch to the digital delay circuit where it is delayed by a specified period. The delayed digital signal is converted to a delayed video signal by a D/A converter. The delayed video signal is applied to a second switch. A dropout detector produces a dropout detected signal when a dropout occurs in the input video signal. The first switch normally passes the digital signal from the A/D converter and is responsive to the dropout detected signal for passing the delayed digital signal from the digital delay circuit back to the digital delay circuit. The second switch normally passes the input video signal as it is and is also responsive to the dropout detected signal for passing the delayed video signal from the D/A converter.

Dropout compensating apparatus using a digital delay circuit

A magnetic recording and reproducing method, applicable to a magnetic recording and reproducing apparatus such as a video tape recorder. The method comprising the steps of recording a first signal in a magnetic layer of a magnetic tape by a first head, recording a second signal which is preferably a digital signal in a shallower portion of the first signal recorded magnetic layer by a second head having a different azimuth from that of the first head. The width of the shallower portion is preferably narrower than the width of the first signal recorded magnetic layer. The recorded first and second signals are reproduced by heads having different azimuth from each other, respectively, so as not to interfere with each other.

Method of recording and reproducing video and audio signals on a

A digital noise reducing apparatus improves the signal to noise ratio (S/N) of a luminance signal of a video signal reproduced from a recording medium. This apparatus includes: an analog to digital (A/D) converting circuit for converting the luminance signal into a digital luminance signal; a digital delay circuit for delaying the digital luminance signal by one horizontal scanning period (1H); a first calculating circuit for calculating the difference between the digital luminance signal and the delayed digital luminance signal; a limiting circuit for limiting the amplitude of an output signal of the first calculating circuit, and a second calculating circuit for subtracting a signal output which is from the limiting circuit from the digital luminance signal. The apparatus operates to reduce noise at the line offset frequency of the luminance signal.

Digital noise reducing apparatus for a video signal processing recording

A video disc reproducing apparatus is provided with a pickup by which the information recorded on a video disc is detected as a variation in electrostatic capacity. The signal output from the pickup is processed so as to generate a control signal proportional to the logarithm of the pickup signal. This control signal is then utilized to control the pressure of the pickup on the video disc. Element functions of the apparatus may be combined such that an automatic gain control device may also serve to generate the logarithmic control signal.

Video disc reproducing apparatus

A magnetic recording/reproducing apparatus has a rotor drum with a group of rotary magnetic heads mounted thereon, a reproducing amplifier, a recording/reproducing mode switching circuit, a head selection circuit, a control circuit and a DC voltage source. The control signal circuit and the DC voltage source receive a control signal transmitted from a stator drum through a rotary transformer and produce signals for controlling the mode switching circuit and the head selecting circuit and a DC voltage for energizing all the circuits on the rotor drum, respectively.

Magnetic recording and reproducing apparatus

A tracking-error correcting system in a rotary head magnetic recording and reproducing apparatus in which reproducing magnetic heads are mounted on a respective bimorph leaf having piezoelectric elements so as to be movable in the direction of the axis of rotation. The piezoelectric elements are controlled by a control voltage which is produced by adding a signal from an auto-tracking circuit and a signal from a triangular wave generating circuit. In a reproducing mode at a tape speed which is different from a tape speed in recording mode, this system activates the auto-tracking circuit when the control voltage level is within a limited range which is detected by a control voltage detector. Also, this system stops the auto-tracking circuit during a transition period when the reproduction mode changes.

Control of auto-tracking in tracking-error correcting system of video

An automatic tracking apparatus, by which a tracking condition of reproducing heads and a recorded track can be automatically adjusted. This apparatus has a rotary heads, an envelope detector, and a filter. A tracking error signal is generated by detecting the envelope of a video signal which does not contain chrominance signal components, the video signal being derived from the rotary heads. As a result, the tracking error signal includes only the luminance signal but does not include the signal from the next track. Therefore, the envelope signal is a good tracking error signal which is only responsive to the signal level of the objective track.

Eliminating the low-frequency chrominance signal for tracking in a video

In a rotary head magnetic recording and reproducing system, the number of horizontal synchronous signals which occur between the vertical synchronous signals are kept almost constant by delaying the video signal of the field following the one in which a shift of a track has been detected, the operation occurring when the system is in the abnormal reproducing mode in which the speed of the magnetic tape in the reproducing mode is different from the speed of the magnetic tape in the previous recording mode.

System for eliminating vertical TV picture fluctuations appearing in

A video signal recording/reproducing apparatus includes a first set of rotary heads mounted on a rotary disk and a second set of rotary heads mounted on head actuators which are also mounted on the rotary disk. The apparatus has two reproduction modes. A magnetic tape in the first reproduction mode is driven at a speed equal to the speed used in a recording mode. The magnetic tape in the second reproduction mode is driven at a speed which is different from the speed used in the recording mode. The apparatus has a negative feedback loop which detects the reproduced signal level of the second set of rotary heads and drives the head actuators in order to increase the reproduced signal level of the second set of rotary heads. In the first reproduction mode, the negative feedback loop is intermittently closed. At the period of time when the negative feedback loop is open, the negative feedback loop holds the value of its output signal to that of the last time period when the negative feedback loop was closed, and, in addition, the head actuator is not driven when the feedback loop is open. At a transitional period when the apparatus switches from the first reproduction mode to the second reproduction mode, a holding signal from the negative feedback loop is supplied to the head actuator.

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Neyagawa, Japan

Masao Tomita