Abstract: A read/write amplifier provides a magnetic disk unit capable of reducing variations of the bias voltage. An output stage provides a DC bias circuit for the read signal and a circuit for producing a high impedance for the read signal. A switch circuit is in a closed circuit operation only when a chip select signal is received. The output stage provides a switching order to connect a constant current circuit to the amplifier circuit at read time and to connect the DC bias circuit at the write time.

Abstract: A video signal is duplicated in a reduced time by using n video tape recording devices having rotary heads reproducing the video signal from respective recording media at a normal rotary head rotational speed and transporters transporting the respective recording media at n times a normal transport speed. The reproduced video signals are offset from each other by one frame of the video signal, and are timebase compressed, selectively delayed and combined into an n times normal speed reproduced signal, that is, a video signal with its timebase compressed by 1/n. The n times normal speed reproduced signal is recorded by at least one video tape recorder on a recording medium at an n times normal recording speed, thereby duplicating the original video signal. An audio signal may also be duplicated in this manner.

Abstract: In accordance with an illustrative embodiment of the present invention, a magnetic tape which has seismic data thereon and which has been stored for so long that stiction is a problem is temporarily placed in an environmentally sealed room and subjected to a temperature of about 140.degree. F. and a relative humidity of 20% or less for about 48 hours. After removal from the room and cooling down to ambient temperature of about 70.degree. F. in the presence of relative humidity of about 50%, the tape is cleaned and retensioned on a reel. The data then can be read out onto another media with recovery of practically 100% of the seismic data.

Abstract: A magnetic disk drive is disclosed which has a tunnel erase head assembly comprising a read/write head for writing and reading data on a magnetic disk, and a pair of tunnel erase heads for trimming a pair of opposite marginal edges of the record track being formed by the read/write head, with the consequent formation of spaces intervening between the record tracks. The spaces created on the same disk by different disk drives may be of one polarity of magnetization or the other, with the possibility of noise production due to an abrupt change in the polarity of magnetization as the read/write head scans any of the spaces as a result of mistracking. For the reduction of such noise the coil of the tunnel erase heads is connected to an erase current source via a circuit whereby the erase current is made to have a staircase or ramp rise and fall.

Abstract: A system which records and reproduces a digital signal in the form of a magnetic reversal on and from a recording medium includes a magnetic head for reproducing data recorded on the recording medium; an automatic gain control unit for controlling the reproduced signal so as to have a constant amplitude; an equalizer for processing the output waveform from the automatic gain control unit; a differentiator for changing the output from the equalizer to a differentiated waveform; a low pass filter for limiting the signal band of the differentiated waveform; a low pass filter for limiting the signal band of the equalizer output; a pulser for receiving the equalizer output, the band of which is limited by the low pass filter and the differentiated waveform, the band of which is limited; a differentiator for receiving the output from the automatic gain control unit and producing a differentiated signal from the output signal; an attenuator for attenuating the differentiator output; and a waveform processor for addi

Abstract: In a multi-channel data recorder, digital data for recording is converted to words of reduced length, and data for identifying the data channel is added to the reduced-length data words to produce a signal having a word length compatible for recording by a conventional data recorder.

Abstract: A digital signal regeneration apparatus measures regeneration output pulses produced by binary-coding an analog signal acquired by reading information from a recording medium to regenerate a digital signal recorded on the recording medium, comprising a pulse spacing extracting circuit for extracting a pulse spacing of a binary-coded regeneration output pulse, a pulse multiple detecting circuit for detecting a multiple indicating how many times a pulse spacing the pulse spacing extracting circuit extracts is larger than a reference cycle, a reference cycle calculating circuit for calculating a new reference cycle using the pulse spacings and multiples of a plurality of predetermined contiguous regeneration output pulses sent from the pulse spacing extracting circuit and pulse multiple detecting circuit, a clock generating circuit for generating a demodulating clock using the reference cycle the reference cycle calculating circuit calculates, a clock synchronizing circuit for synchronizing a demodulating clock

Abstract: A circuit for monitoring the recorded state of audio signals from a microphone on a magnetic tape. The circuit comprises an additional head having only a playback function. The head functions to detect an audio signal recorded on the magnetic tape. The detected audio signal is then applied to an outer speaker, via a switch. Accordingly, the user can monitor completely the recorded state of the audio signal on the magnetic tape in the record mode operation of audio device.

Abstract: A phase-correction circuit comprises an amplifier, comparators, inverters, an S/R flip-flop, a switch and, a pulse width controller. The circuit sets a reference of recording position of a head to a tape and corrects the phase differences between the head, a magnet and a pulse generator, thereby realizing precise drum phase servo action and acquiring excellent audio and video recording and reproducing.

Abstract: A high density helical scan recording device having write/wide-read heads and RAW/narrow-read heads of different widths to permit an increase in the density of data tracks and to allow backward compatibility for reading and recording conventional density data tracks. The write/wide-read heads are used to record data in tracks of either the conventional density or the high density. The write/wide-read heads are also selected to read conventional density data tracks. The RAW/narrow-read heads have a reduced width that permits reading of data tracks in which greater than two-thirds of each data track has been overlapped by an adjacent data track. The RAW/narrow-read heads are used in a read-after-write (RAW) capacity and are used during a read operation of the high-density data tracks.

Abstract: A helical-scan tape storage device is operative to write computer data to tape according to a predetermined format in which the data is store in tracks arranged in groups. These groups are optionally separated by one or more amble track To enable auxiliary data, such as audio data to be stored within the format, the storage device is arranged to store a succession of N ambles into which the auxiliary data is written. Using the amble tracks to store auxiliary data permits storage devices that have been designed only with regard to computer data storage to read tapes containing both computer and auxiliary data, since the auxiliary-data-containing amble tracks are ignored by such a device. A storage device designed to extract auxiliary data from ambles can readily recover the auxiliary data.

Abstract: A video cassette recorder with a television signal storing function can display simultaneously a current television broadcasting signal as well as the television program content during the tape replacing time in picture-in-picture fashion, by adopting a solid state memory device for storing the television program content during the tape replacing time, without discontinuity of the television program content due to replacing the new tape.

Abstract: In a recording and reproducing apparatus according to the present invention, a drum unit incorporates a first recording/reproducing control head. A second recording/reproducing control head is disposed within a running path of a magnetic tape. A control signal synchronizing with a record starting point of recording tracks is recorded by the first or second recording/reproducing control head. The second recording/reproducing control head is controlled in accordance with a state where the control signal is recorded or reproduced by the first recording/reproducing control head, thus recording or reproducing the control signal. A deviation in tracking which is caused due to stretching/contraction of the magnetic tape can be effectively avoided. The control signals can be recorded or reproduced more surely than in the prior art.

Abstract: A duplicator system is provided which transfers information signals such as video signals recorded on a mother tape to a copy tape. This duplicator includes a counting system to manage the life of a mother tape. The counting system is operable to count the number of traveling cycles of the mother tape traveling through a preselected tape path and records data indicative thereof on a preselected section of the mother tape. Thus, an operator can easily read out the data indicative of the total number of traveling cycles from the mother tape to confirm the remainder of the working life thereof.