Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 sign

Abstract: 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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A rotary magnetic head type recording and/or reproducing apparatus to which a tracking system can be applied, comprises two rotary heads provided opposing a rotary body for alternately and successively recording signals on oblique tracks in a recording medium with respect to the longitudinal direction of the recording medium or for alternately scanning over tracks in the recording medium to reproduce recorded signals, moving mechanism for continuously moving the recording medium, a head moving mechanism for displacing the two rotary heads substantially at the same time in mutually opposite directions by the same amount in a plane which is perpendicular to the rotating plane of the rotary heads, in response to a driving signal supplied from the exterior, and a control head for recording a control pulse having a predetermined period onto the recording medium.

Abstract: In an insert recording system for a video signal, a tape is recorded with a video signal along tracks formed obliquely with respect to the longitudinal direction of the tape, a part of recorded tracks is erased, and a different or new video signal is recorded onto the erased part. The insert recording system comprises one or a plurality of video heads for recording the different or new video signal onto the erased part of the tape, one or a plurality of flying erase heads mounted on a rotary body provided with the one or a plurality of video heads, at a position leading the video head by an angle .theta.

Abstract: A device for detecting the position of a tape in a magnetic tape recording and/or reproducing apparatus comprises a tape guide making contact with a magnetic tape traveling along a specific tape travel path at the side thereof opposite to the side having a magnetic layer surface thereon, a detection head provided in the tape guide at the front side thereof for producing a tape position designation signal on the magnetic tape from the side opposite to the side having the magnetic layer, and a circuit for detecting a desired position of the magnetic tape responsive to detection of the designation signal by the detection head.