Abstract: A digital signal processing apparatus adapted for use in a digital video tape recorder or the like. The apparatus includes a digital multiplexer for combing an input digital information signal and an input digital pilot signal with each other on a predetermined time basis so as to produce a composite recording signal; and a variable gain amplifier supplied with the composite recording signal of the digital multiplexer for amplifying at least one of the digital information signal and the digital pilot signal in the composite recording signal to respective different levels. With a relatively simple circuit configuration and a control action which operates in a relatively straight-forward manner, a relatively high operational reliability is achieved.

Abstract: An apparatus for recording a digital signal composed of a plurality of different types of data. A plurality of rotary heads are coupled together to form a head unit, in which the heads are spaced from each other by predetermined distance in a track pitch direction and in a head scanning direction. A record device supplies the rotary heads with the digital signal for recording in adjacent tracks on a magnetic tape. The digital signal is supplied to the rotary heads in a timed manner such that the areas in adjacent tracks in which the same types of data are recorded are displaced from each other along the tracks by the predetermined distance in the head scanning direction.

Abstract: Digital signal recording and reproducing apparatus for recording digital signals in successive tracks of given pitch on a record medium and for reproducing digital signals therefrom. A rotary head assembly including two pairs of head subassemblies angularly separated by approximately 180.degree., with each subassembly comprised of a pair of heads displaced from each other in a direction parallel to the track pitch, is driven at a predetermined rotation speed to record digital signals selectively supplied at respectively different original transmission rates which exhibit a predetermined ratio. The digital signals are timebase modified to have substantially the same data rate even though their original transmission rates differ from each other; and are coupled to the rotary head assembly.

Abstract: A digital video tape recorder for digitally recording and/or reproducing a video signal. An analog video signal is received and converted to a digital signal which is supplied to a time base corrector for correcting a time base error in the input video signal by writing the digital signal into a memory in response to a synchronizing signal derived from the input video signal and reading out the stored digital signal from the memory in response to a reference signal. The output signal of the timebase corrector is processed and recorded on a magnetic tape by a rotary head.

Abstract: In a playback phase correction apparatus for a video recorder, a signal level of an input signal is compared with predetermined reference levels at times according to a playback clock signal. The apparatus operates to continuously detect whether the phase of the playback clock approaches or recedes from a point in time at which the eye pattern of the input signal is at a maximum value by comparing a count value obtained from the comparison results of the reference level counts from a previous cycle with those of the current cycle. Then, the apparatus controls a playback clock delay circuit on the basis of these count values so than an optimal count value is continuously maintained, thus ensuring that the timing of the playback clock is maintained in synchronization with the maximum eye pattern interval of the input signal.

Abstract: An apparatus for processing an input data signal has a generator providing a plurality of pseudo-random signals each of which scrambles the input data signal for providing a plurality of respective scrambled outputs, a detector by which a DC component, such as, a run-length or a digital sum value, is detected for each of the scrambled outputs, and a selector responsive to the detector for selecting one of the scrambled outputs, for example, having a minimum run-length or a digital sum value closest to zero. An identifying signal identifying the pseudo-random signal used in scrambling the selected scrambled output is then transmitted with the latter, for example, by recording on a magnetic tape. When the transmitted signal is received or reproduced, the identifying signal included with it is detected, and the received signal is descrambled with a pseudo-random signal corresponding to the detected identifying signal.

Abstract: Apparatus for regenerating a coded digital signal, comprising an interference cancellation equalizer for cancelling an interference component from an input digital signal and a decoder. The equalizer includes a compensator for high frequency compensating the input digital signal, an extractor for extracting intercode interference from the compensated digital signal, and a subtracter for subtracting the extracted intercode interference from the input digital signal to produce a waveform equalized signal. The decoder recovers the original digital signal as a function of the correlation or samples of the waveform equalized signal.

Abstract: In a system for recording digital data obtained based on an information signal on a magnetic tape and/or reproducing digital data obtained based on an information signal from a magnetic tape, a magnetic recording apparatus comprises an encoder for producing, based on the information signal, one of plural kinds of digital data which have different transmission rates respectively, a time base processor for selectively converting a time base of digital data obtained from the encoder so as to produce modified digital data having a predetermined transmission rate, a recording modulator for producing a recording signal corresponding to the modified digital data, a recording portion provided with a rotary magnetic head device to which the recording signal is supplied and a tape guide for guiding the magnetic tape and operative to cause the rotary magnetic head device to contact with the magnetic tape for forming oblique record tracks on the magnetic tape, a head driver for rotating the rotary magnetic head device at

Abstract: In an apparatus for magnetically recording and/or reproducing digital signals in a plurality of modes characterized by different respective formats, pilot signals having different frequencies are generated to identify the modes, respectively, and, during a recording operation in one of such modes, the respective pilot signal is mixed with the digital signal to be recorded for providing a resultant mixed signal which is recorded. Thereafter, during a reproducing operation of the apparatus, the pilot signal included in the reproduced mixed signal is detected for determining the format of the recorded signal on the basis of the frequency of the detected pilot signal, whereupon the respective mode of the apparatus is established.

Abstract: Data reproducing apparatus for reproducing data that is recorded with a selected one of at least two different recording densities such that the played back data may exhibit different frequency characteristics, depending upon the recording density. The played back data is supplied to a selected one of plural equalizer circuits whose respective equalizing characteristics match the frequency characteristics of the played back data, thereby reducing the bit error rate of the played back data, regardless of the particular recording density with which that data had been recorded.

Abstract: An apparatus for decoding a transmitted signal has a receiver for receiving the transmitted signal, a filter for limiting the frequency of the output of the receiver below a predetermined frequency, a generator for generating a clock signal having a frequency equal to a transmitting rate of the signal output from the receiver, a converter for sampling the output of the filter at a frequency defined by the clock signal and for converting the filter output into a binary signal, and a processor for decoding the binary signal according to a predetermined system.

Abstract: In an apparatus for recording data on a magnetic recording medium by means of a magnetic head, a recording current supplied to such head, for example, from a recording amplifier, is varied in accordance with the recording density of the data being recorded so as to reduce the bit error rate upon playback or reproducing of the recorded data. For each recording density, the recording current supplied to the magnetic head is a predetermined amount greater than the optimal value of the recording current at a Nyquist frequency of the digital data being recorded.

Abstract: In an apparatus, such as, an 8-mm VTR, in which a pilot signal and a digital signal modulated by an information signal, and occupying frequency bands that overlap at least in part, are recorded together as an addition signal in a track on a recording medium; a D.C. component of the addition signal reproduced from the track is detected and compared, in a voltage comparator, with the level of the reproduced addition signal so as to provide the digital signal as an output of the comparator, and such output of the voltage comparator is subtracted from the reproduced addition signal so as to provide the pilot signal without error by reason of the digital signal. Further, the pilot signal and cross-talk from adjacent tracks obtained from the first-mentioned subtraction is, in turn, subtracted from the reproduced addition signal for obtaining the digital signal therefrom, and the D.C.

Abstract: In a digital data reproducing apparatus for demodulating digital data recorded on a magnetic medium with either a first or second record modulation mode, such mode is detected by identifying the frequency of a recovered clock signal derived from the digital data by a clock recovery circuit, and an appropriate demodulation circuit for the recording mode is then selected to demodulate the reproduced digital data.

Abstract: A digital recording and reproducing system for ME tape uses a class 4 partial-response encoder in the recording apparatus and a corresponding decoder in the reproducing apparatus. A high signal-to-noise ratio is achieved without the need for a phase equalizer.

Abstract: A clock regeneration circuit for use in data reproducing apparatus which reproduces and demodulates digital data that has been recorded on a magnetic medium in accordance with different types of modulation having different recording densities, such as biphase-mark modulation and 8-10 modulation, respectively. The clock regeneration circuit includes a phase locked loop for regenerating a clock signal from the clock component included in the reproduced data and comprises a switchable voltage controlled oscillator for selecting the frequency of a reference signal generated thereby in correspondence with the type of modulation which had been used for recording. Also included in the clock regeneration circuit is a phase comparator and a switchable low pass filter for supplying the output of the phase comparator to the voltage controlled oscillator, the time constant of the filter being selected in correspondence with the type of modulation that was used for recording.