Abstract: In a magnetic recording and reproducing apparatus in which a frequency-modulated video signal and a frequency-modulated audio signal are frequency-multiplexed and the frequency-multiplexed signal is recorded on video tracks of a magnetic tape, and the recorded signal is reproduced, a noise produced in the audio signal due to video track switching in the signal reproduction is eliminated by holding the audio signal for a period of noise duration.

Abstract: A digital signal recording and reproducing apparatus comprising a dynamic range compression/expansion apparatus. The compression/expansion apparatus receives a digital signal from, for example, an analog-to-digital converter and compresses the dynamic range of the digital signal and the so compressed digital signal is supplied to a recording signal processing circuit in the recording operation mode, while the apparatus receives a digital signal reproduction output from a recording/reproducing head and expands the dynamic range of the reproduced digital signal and the so expanded digital signal is supplied to, for example, a digital-to-analog converter in the reproducing operation mode.

Abstract: A tracking controlling device is provided which is suitable for a rotating head helical scanning-type magnetic video signal recording and reproducing apparatus in which pilot signals of a plurality of frequencies are recorded in advance on tracks on a magnetic tape such as to be superimposed on video signals, and the pilot signals are reproduced during reproduction so as to effect tracking control. This tracking controlling device comprises means for separating and detecting two reproducing pilot signals from both tracks adjacent to the track being scanned by the rotating head, a comparator for comparing the magnitude of the reproducing pilot signals from the adjacent tracks and for generating a binary PWM signal in accordance with the magnitude, and controlling means for controlling the rotation of a capstan motor for driving the magnetic tape using the tracking error signal converted into the form of the PWM signal obtained by the output of the comparator.

Abstract: A helical scanning type magnetic recording and reproducing apparatus records a signal representing recording conditions on a magnetic tape when a recording is effected thereon, together with a PCM audio signal. At the time of reproduction, reproducing conditions are controlled so as to be the same as the recording conditions on the basis of the signal representing recording conditions reproduced.

Abstract: A magnetic recording/reproducing apparatus in which at least two recording and reproducing magnetic heads are mounted on a rotatable cylinder with an angular distnce of 180.degree. therebetween, wherein audio signals having undergone a pulse code modulation are recorded on record tracks slanted relative to the longitudinal direction of a magnetic tape wrapped around the rotatable cylinder. The record track is divided trackwise into a plurality of channels. The audio signals are recorded on the channel basis. The magnetic tape is transported in a forward or backward direction while recording or reproduction is conducted. The rotatable cylinder has mounted thereon a first erasing head rendered operative when the magnetic tape is transported in the forward direction and a second erasing head operative when the magnetic tape is transported in the backward direction for erasing only the audio signal of a given channel on the record track.

Abstract: An audio signal transmission system having a noise reduction circuit, which includes a transmission medium such as a magnetic tape to be used to transmit a digital signal converted from an input audio signal and thereafter to output the audio signal reproduced from the digital signal, a digital signal transmitter having a pulse-code modulator and demodulator (MODEM). The noise reduction circuit includes a compressor for compressing the dynamic range of the input audio signal according to the detection level obtained by detecting at least the high-frequency components thereof in order to supply the output from the compression to the digital signal transmitter and an expander for expanding the dynamic range of the demodulated signal from the transmitter according to the detection level of at least the high-frequency components thereof.

Abstract: An apparatus for detecting and compensating for the drop-out in a video tape recorder in which an FM audio signal is recorded on a magnetic tape and is reproduced therefrom utilizing a rotary magnetic head. In a playback mode, a frequency demodulator demodulates the reproduced FM audio signal. The reproduced FM audio signal is supplied to a synchronous detector and synchronously detected with an output signal of the frequency demodulator. An output signal of the synchronous detector is supplied through an integrator to a drop-out discriminator which detects a drop-out generating period and provides an output indicative thereof.

Abstract: In a magnetic recording and reproducing apparatus of 2-head helical scan type, an overlapping portion is formed at one end of each video track on a magnetic tape, and a PCM audio signal is recorded on this overlapping portion. Video/audio selective switching circuits are disposed on the input or output side of video and audio recording amplifiers, and video/audio selective switching circuits and video/audio playback equalizer circuits are disposed on the output side of video and audio playback amplifiers. Each of the heads acts as both of a video head and an audio head.

Abstract: A helical scanning type video tape recorder is provided with an audio signal recording/reproducing circuit in which the audio signal is submitted to frequency modulation, after which the modulated audio signal is recorded on a video track by a rotary video head while a video signal is also recorded on the same track. This provides very good quality of reproduction of the audio signal. In order to reduce crosstalk interference of audio signals between adjacent tracks, a dynamic range of the audio signal is compressed to have a predetermined characteristic in the recording process, and then expanded to compensate to the original dynamic range in the reproducing process.

Abstract: A modulator-demodulator suited to record an audio signal in a recording medium in the form of a frequency-modulated signal and to demodulate the frequency-modulated signal is disclosed. It includes a voltage-controlled oscillator, a switching circuit for changing one of two input frequency-modulated signals toward a control input of the voltage-controlled oscillator, and a phase detector for detecting a difference in phase between the frequency-modulated signal reproduced from the recording medium and the output signal of the voltage-controlled oscillator. In a recording operation, an input audio signal is supplied to a control signal input terminal of the voltage-controlled oscillator through the switching circuit, and the VCO acts as a modulator for carrying out frequency modulation.

Abstract: A sound signal recording and reproducing device for use in a picture signal recording and reproducing apparatus comprises a first sound signal recording and reproducing system recording a sound signal in superposed relation with a picture signal on the same track on a magnetic tape by a rotary head, and a second sound signal recording and reproducing system capable of recording a sound signal independently of the picture signal by a stationary head in a direction parallel with the traveling direction of the magnetic tape.

Abstract: A magnetic picture signal recording/reproducing apparatus in which a picture signal recorded on a magnetic tape is read out by a magnetic head for reproduction. First and second resonance circuits having respective resonance frequencies in the vicinity of a frequency of a carrier signal corresponding to a white peak level of the picture signal and in the vicinity of a frequency corresponding to an average level of the picture signal, respectively, are connected in cascade, to thereby prevent the white peak level of the picture signal from being attenuated.

Abstract: In an apparatus for recording a frequency modulated audio signal and a frequency modulated video signal on the frequency multiplex basis onto the same recording track, a muting circuit is necessary so that the reproduced audio signal is not outputted when a dropout takes place and/or when the frequency modulated audio signal is missing on the track. The muting circuit is controlled not only by the output signal of a dropout detector, but by a signal obtained by integrating the dropout detection signal so that the audio output is blocked during a frequent occurrence of dropout. The muting circuit includes a previous value holding circuit serving to hold its output at an input level immediately before the control signal has been given, the previous value holding circuit being arranged in the reproduction audio signal processing system following a demodulator.

Abstract: A previous level holding circuit is connected to an output of an FM demodulator to eliminate dropout disturbance from a reproduced audio signal from a record medium on which an FM-modulated audio signal has been recorded. The previous level holding circuit is controlled by an output of a circuit for detecting dropout in the reproduced signal and comprises a gate circuit operable in response to a dropout detection signal and a capacitor. During the occurrence of dropout, the previous level holding circuit holds and produces the reproduced output level assumed immediately before the dropout to eliminate the noise due to the dropout.

Abstract: A frequency converter circuit suitable for being constructed in the form of an integrated circuit and adapted to the frequency conversion of a carrier chrominance signal for recording and reproducing chrominance video signals basically comprises a full balance type differential amplifier including three sets of paired differential transistors. Two sets of paired differential transistors, in which the collector of one transistor of one paired differential transistors is connected to that of the corresponding one transistor of the other paired differential transistors and the collector of the other transistor of the one paired differential transistors is connected to that of the other transistor of the other paired differential transistors, are provided for the output stage and have those collectors each connected to the respective emitters of grounded base transistors. The grounded base transistors have their collectors each connected to a load resistor.

Abstract: An apparatus for recording a color television signal on a recording medium by converting a carrier color signal in the color television signal to a low frequency band signal and reproducing the color television signal by converting the recorded low frequency band carrier color signal to the original high frequency carrier color signal is disclosed.

Abstract: A recording apparatus extracting and recording for reproduction a video signal of a still-picture out of a received multiple signal, which video signal is divided for every several horizontal scanning lines and inserted in the vertical fly-back period of an ordinary television signal included in the multiple signal, comprises means for extracting and recording sequentially the video signal for a still-picture from out of the vertical fly-back period of the television signal, and means for extracting by detection of that vertical synchronizing signal of the television signal which is the nearest to a position where the vertical synchronizing signal of the video signal for a still-picture should be located, and for recording the extracted vertical synchronizing signal together with the extracted video signal for a still picture.

Abstract: A synchronizing signal regenerator for regenerating all the required synchronizing signals from a composite signal having a plurality of synchronizing signals having a different repetition period and phase. The composite signal comprises a video signal and a pulse code modulated audio multiplex signal arranged in a predetermined sequence. The composite signal further comprises a first synchronizing signal consisting of a certain predetermined pulse series synchronized with a modulated pulse series of the audio multiplex signal and a second pulse code modulated synchronizing signal including a plurality of other synchronizing signals required for the reproduction of the video signal and the audio multiplex signal. The synchronizing signals are inserted at a certain predetermined portion in the video signal and in the audio multiplex signal.