Victor Company of Japan, Limited

Yasuomi Namiki

Yukinobu Ishigaki

Masaru Tanaka

Kazutoshi Hirohashi

Yoshio Tokuyama

Satoshi Kawasaki

Koji Arai

Hisashige Fujiwara

Hiroshi Nishiumi

Mitsuhiro Arai

Akihiko Sasaki

Takano Takashi

Kouji Arai

A helical scan type playback apparatus comprising a plurality of magnetic heads, a position signal generation element for generating a signal indicative of each position of these magnetic heads, and a switching element for video signals played back by the plurality of magnetic heads in response to the position signal from the generation element, particularly a playback apparatus for information recorded on a video tape in which the phase of a low frequency band color signal is altered every track of a video tape on the basis of a predetermined rule, thereby allowing spectra of color signals not to overlap with each other between adjacent tracks. This playback apparatus comprises an element for storing the position signal after a first predetermined time has passed from the time when a vertical synchronizing signal of the video signal is received, and a readout element for reading out the position signal stored in the storage element after a second predetermined time has passed from the time when the vertical synchronizing signal is received, and outputting it.

Helical scan type playback apparatus for video data recorded on magnetic

There is disclosed a magnetic recording and reproducing apparatus provided with a rotary drum wherein audio heads for recording/reproducing an audio signal, video heads for recording/reproducing a video signal, an erasing head for erasing recorded information are provided on the outer circumferential surface of the rotary drum, and a running magnetic tape is obliquely wound at a predetermined length on the outer circumferential surface. This apparatus is constituted so that, in an audio recording mode for recording the audio signal onto the tape by the audio heads, after a signal recorded on the tape is erased by the operation of the erasing head, the audio heads record onto the magnetic tape both signals of the audio signal and a control signal used for tracking servo at the time of reproducing operation, and that, in a video recording mode for recording the video signal at the surface layer portion of the tape by the video heads, the erasing head is inoperative, and, under the same state as the reproducing mode in which the servo system is synchronous with an input video signal, the video heads record the video signal at the surface layer portion of the tape of a track on which the audio signal has been recorded in the audio recording mode while carrying out tracking servo on the basis of the control signal reproduced from the tape.

Magnetic recording and reproducing apparatus

A high-speed erasing apparatus for use in a magnetic recording/reproducing system for erasing a recorded signal on a magnetic tape traveling along a predetermined path. The erasing apparatus comprises a flying-erasing head mounted on a rotary cylinder of the system, a full-erasing head disposed at a preceding position of the flying-erasing head in a traveling direction of the tape, and an audio-erasing head provided at a succeeding position thereof in the traveling direction. Also included in the apparatus are a high-speed erase oscillating circuit for supplying the full-erasing head with an output having a frequency higher than N times of the upper limit of the audible range, a video-erase oscillating circuit for supplying the flying-erasing head with an output having a frequency higher than the upper limit of a video signal range, and an audio-erase oscillating circuit for supplying the audio-erasing head with an output having a frequency higher than the upper limit of the audible range. The oscillating circuits are driven so that, at the initial time, the recorded signal is erased by all of the erasing heads with the tape being transported at the industry standard traveling speed and the high-speed erase oscillating circuit is operated so as to, after elapse of a predetermined time, erase the recorded signal by only the full-erasing head with the tape being transported at N times of the industry standard traveling speed.

High-speed erasing apparatus for use in magnetic recording/reproducing

A magnetic recording/reproducing apparatus for magnetically recording and reproducing information on and from a magnetic tape. The apparatus includes a rotary drum adapted to be rotatable about its own axis and having at its circumferential portions a plurality of magnetic heads including at least first and second signal recording/recproducing magnetic heads and one signal erasing magnetic head. In order for coupling between the plurality of magnetic heads and a recording/reproducing circuit of this apparatus, further included is a rotary transformer which is provided between the rotary drum and a stationary portion of this apparatus and which includes first and second transformer coil assemblies coupled to the first and second magnetic heads, respectively, and one erasing coil assembly coupled to the erasing magnetic head. The erasing coil assembly is disposed between the first and second transformer coil assemblies to assume a magnetically neutral position with respect thereto. The recording/reproducing circuit is arranged so that the directions of recording currents through the first and second transformer coil assemblies are in reverse relation to each other, whereby induction currents due to magnetic fluxes produced by the recording currents therethrough are cancelled each other in the erasing coil assembly.

Rotary transformer with winding to cancel crosstalk

A noise reduction circuit is provided with a slew rate detection circuit for detecting a slew rate of a reproduced audio signal, and variably controls a pulse width of a hold signal depending on the detected slew rate. The noise reduction circuit successively produces the reproduced audio signal with a predicted level other than a level of pulse noise included in the reproduced audio signal during a time period corresponding to the pulse width of the hold signal, so as to obtain a reproduced audio signal in which the pulse noise has been eliminated.

Noise reduction circuit for reducing pulse noise in audio signal

A magnetic head switching circuit for a magnetic recording and reproducing apparatus having a recording and reproducing magnetic head has three switching circuits. The first switching circuit is coupled between ground and one end of a winding of the head and controlled between conducting and non-conducting states in response to a voltage applied to a first control terminal. The second switching circuit has an output end, an input end coupled to a D.C. power source, and a second control terminal supplied with a mode switching signal for assuming a non-conducting state in the recording mode and assuming a conducting state in the reproducing mode to guide a voltage at the input end to the output end in response to the mode switching signal. The third switching circuit has an input end coupled to the output end of the second switching circuit and an output end coupled to the first control terminal. When the second switching circuit is in the conducting state, the third switching circuit guides a voltage at the input end of the third switching circuit to the output end of the third switching circuit so as to apply this voltage to the first control terminal and put the first switching circuit into the conducting state.

Magnetic head switching circuit for magnetic recording and reproducing

A rotary head type magnetic recording and reproducing apparatus comprises a circuit for recording and reproducing a signal on and from a magnetic recording medium by rotary heads, a circuit for obtaining a frequency modulated (FM) audio signal by frequency-modulating a carrier by an audio signal which is to be recorded, a circuit for generating a frequency drift detection signal having a constant frequency which does not exist within a frequency range occupied by the FM audio signal, a circuit for obtaining a frequency multiplexed signal by frequency-multiplexing the FM audio signal and the detection signal, a circuit for separating the FM audio signal and the detection signal from the signal reproduced by the rotary heads, a demodulating circuit for obtaining an audio signal by frequency-demodulating the separated FM audio signal, a detecting circuit for frequency-demodulating the separated detection signal and for detecting a frequency drift component, a circuit for forming a frequency drift correction signal responsive to the output of the detecting circuit, and a circuit for correcting a frequency drift component in the output audio signal of the demodulating circuit by the correction signal.

Audio magnetic recording and/or reproducing apparatus utilizing

A video signal recording and/or reproducing apparatus comprises a switch for interrupting a recording when manually turned ON and for resuming the recording when manually turned OFF, a circuit for moving a tape in a forward direction during a recording mode, stopping the tape after moving the tape in a reverse direction over a predetermined distance responsive to an ON state of the switch and moving the tape in the forward direction responsive to an OFF state of the switch, a circuit for generating a joint indication signal and a recording interruption indication signal responsive to the ON state of the switch, a circuit for recording the joint indication signal on the tape and for reproducing the joint indication signal from the tape when the tape moves in the forward direction after being moved in the reverse direction and stopped, a circuit for producing a recording start command signal responsive to a detection of a reproduced joint indication signal, and a circuit for interrupting a recording of a video signal on the tape responsive to the recording interruption indication signal and for resuming a recording of another video signal on the tape responsive to the recording start command signal.

Video signal recording and/or reproducing apparatus having a function of

A delay time adjusting system comprises a comparing circuit for comparing levels of reproduced frequency modulated signals from a pair of rotary heads which simultaneously scan over a magnetic tape, where the rotary heads have gaps of mutually different azimuth angles, a head selecting circuit responsive to an output signal of the comparing circuit, for selectively producing the reproduced signal from the rotary head having the greater level, a signal processing circuit for obtaining a reproduced video signal from the reproduced signal which is selectively produced from the head selecting circuit, a variable delay circuit for delaying the reproduced video signal from the signal processing circuit by a delay time, and a delay control signal generating circuit for variably controlling the delay time of the variable delay circuit so that the variable delay circuit produces a reproduced video signal in which reproduced horizontal synchronizing signals have a constant period.

Delay time adjusting system for video signal reproducing apparatus

In a noise reduction circuit, a sampling pulse is generated for opening a switch in time-coincident relationship with a signal portion which is affected by a noise impulse. During tracking modes the signal is passed through the switch to a junction between a capacitor and a noninverting amplifier to charge the capacitor to the level of the signal. During a sampling mode the switch is open to block the signal. A feedback circuit having plural time constant values is connected between the output and input of the amplifier to provide primary and secondary differentiation of the output signal of the amplifier. The feedback circuit is disabled during tracking modes to enable the amplifier to linearly amplify the voltage developed across the capacitor and is enabled during the sampling mode to differentiate the voltage that occurred immediately before the switch is turned off for application to the input of the amplifier for linearly interpolating the noise-affected portion of the signal.

Noise reduction by linear interpolation using a dual function amplifier

In a video tape recorder of a helical scan type, a low frequency index signal and a high frequency signal are simultaneously applied to a full erase head (FE) with the high frequency signal acting as a bias prior to the recording of a video program. After the index signal has been recorded, the application of the high frequency signal is continued to erase a prerecorded material. The high frequency biasing prevents the index signal from interfering with the video signal during playback.

VTR Circuit arrangement for recording index signal

In a noise reduction circuit, a sample-and-hold circuit operating on a tracking mode is sampled in response to the occurrence of a noise impulse. The voltage sampled is stored in the capacitor of the sample-and-hold. A slope detector is responsive to the capacitor voltage for generating an output representative of the rate of variation of the capacitor voltage. A voltage-to-current converter is connected between the output of the slope detector and the capacitor for converting the voltage to a corresponding current and injecting the current to the capacitor when the rate of variation is positive and draining the current from the capacitor when the rate is negative.

Noise reduction by linear interpolation using a single sample-and-hold

A signal recording and/or reproducing system is provided in a recording and/or reproducing apparatus having a control head for performing recording and/or reproduction of a control signal with respect to a control track on a tape, and a control circuit supplied and controlled by a reproduced control signal. The signal recording and/or reproducing system comprises a switching circuit for only passing signal parts in a signal reproduced by the control head which are required in the control circuit for control, a circuit for obtaining a signal which has passed through the switching circuit as a reproduced control signal and supplying this reproduced control signal to the control head, a modifying circuit for modifying signal parts recorded on the control track other than the signal parts required in the control circuit for control, and a discriminating circuit for discriminating signal parts within a reproduced signal obtained by reproducing the control track by the control head which are modified by the modifying circuit, to produce a discrimination signal.

Signal reproducing apparatus having means for modifying a pre-recorded

An electromagnetic transducer head assembly for use in magnetic recording comprises a ferromagnetic core structure (1'; 30) having a magnetic gap and a winding (1'; 31) mounted on the core structure. A capacitor (3; 34) is mounted in proximity to and connected to the winding to form a resonance circuit. An amplifier circuit (4; 38) is also mounted in proximity to and connected to the resonant circuit for generating an alternating current in the winding.

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Yokohama, Japan

Yasuomi Namiki