Abstract: A method of producing a tracking control signal in a rotary head type magnetic recording and reproducing apparatus and a rotary head type magnetic recording and reproducing apparatus capable of a proper tracking by the use of the tracking control signal.

Abstract: A method and an apparatus for recording and reproducing a PCM audio signal either alone or together with a video signal, using a rotary-head type scanner. An analog audio signal is converted into a digital signal having a predetermined number of quantization bits in each predetermined sampling period. The digital signal is recorded on a recording medium such as a magnetic tape, and an analog audio signal is reproduced from the digital signal reproduced from the recording medium. In the reproducing mode, the signal reproduced from the tape is written into a memory where error detection, correction and deinterleaving are carried out, and the signal is then read from the memory and applied to a D/A converter. The write rate from the memory depends on the video field period, and the read rate depends on the sampling period. Accordingly, the difference between the write address and the read address of the memory depends on the difference between the field period and the sampling period.

Abstract: A digital signal reproducing apparatus in which the frequency of a basic clock signal generated from a clock generator having a fixed oscillation frequency is divided to produce a clock signal used for processing a digital signal, and, when the transmission speed of the digital signal is changed, the frequency division ratio is also changed to produce a clock signal synchronous with the digital signal transmitted at the changed transmission speed.

Abstract: In a recording and reproducing apparatus wherein a video signal and an audio signal are recorded on the same recording track, a signal subjected to a quadrature differential PSK modulation with PCM audio signal is generated as an audio recording signal. The audio recording signal is disposed between occupied bands of FM luminance signal and down converted chrominance signal in a video recording signal and also recorded on a track where the video recording signal is to be recorded.

Abstract: An integration type D/A and A/D converter having improved linearity and low power consumption. Logic circuits such as ECL counters consuming a major part of power of the D/A and A/D converters are realized through CMOS process. Current source circuits, current switch circuit and comparator circuit of the integration type A/D converter are realized in IC through bipolar process ensuring high accuracy and low noise. Logic parts such as counter is realized through CMOS process.

Abstract: In a method of transmitting digital data including the steps of constructing one block by a plurality of digital data, constructing one frame by a plurality of blocks, adding two kinds of mutually different error detection and correction codes to these blocks and transmitting these digital data together with the codes that are added, the digital data are not interleaved, only the error detection and correction codes are interleaved and these interleaved codes are added to the digital data.

Abstract: In a recording operation by a rotary head type PCM recording/reproducing apparatus including at least two magnetic heads, the odd-numbered sample data and the even-numbered sample data are discriminatively extracted and stored. The stored data corresponding to an amount of data outputted from the A/D converter within a predetermined time is selectively read out and supplied to the two heads to thereby record the data in such a manner that the odd-numbered data and the even-numbered data are recorded separately on a track basis or alternatively recorded separately on a preceding half and a succeeding half of each track. The error detecting and correcting code is prepared on the basis of the data to be recorded in each track. In reproduction of the recorded data, upon detection of a drop-out of the data from one of the two heads, the drop-out data is corrected through interpolation procedure to thereby reconstitute the original analog signal.

Abstract: Error detection/correction codes appended to a recording signal for a PCM recorder are so arranged as to ensure detection and/or correction of a dropout or error of a data block address in the reproduction of the recording signal. In recording digital signals on a recording medium, the digital signals are formatted in n-word blocks, each block further including a sync signal for providing a reference timing for the reproduction of the signal, control data related to the digital signals, a data block address for identifying the block of n-words, an error detection code for detecting an error in the control data and the block address, and an error detection/correction code for error detection and/or correction for the block address and the n-words. A recording system includes an error detection/correction code generating circuit which generates error detection/correction codes using a Reed Solomon code or b-adjacent code.

Abstract: Digital companding without range bits involves comparison of a digital input with predetermined boundaries separating a plurality of numerical ranges, detection of a numerical range to which the digital input belongs, generation of an off-set unique to each numerical range, bit-shifting of the digital input, and addition of the bit-shifted input with the generated off-set to provide a companded digital output which is in one-to-one correspondence to the digital input. The off-set values are stored in a memory.

Abstract: This invention relates to an error correction upon reproduction of digital signals. The error correction is performed by decoding code words such as cross-interleaved Reed Solomon codes, in which first code blocks are formed by a plurality of information words which are in the first arrangement state and a plurality of first check words which are produced by codes associated with the plurality of information words with a Hamming distance of d.sub.1, and second code blocks are formed by a plurality of information words and a plurality of first check words which are in the second arrangement state and which consist of the said plurality of information words and the said plurality of first check words which are respectively included in the different first code blocks, and by a plurality of second check words which are produced by codes associated with the plurality of information words and the plurality of first check words with a Hamming distance of d.sub.2.

Abstract: The recording area of the magnetic tape is divided into a first area for recording a PCM converted audio signal and a second area for recording a PCM converted video information. In recording the audio signal and the video information which have been separately PCM converted, the magnetic tape is wrapped around the rotary heads so that a wrap angle of each of said first and second areas is less than 90.degree. with respect to the rotary heads of a predetermined diameter.

Abstract: A method of transmitting a digital signal in the form of successive signal frames containing codes for detecting and correcting errors of the digital signal for reducing degradation in the quality of the reproduced sound due to generation of the code errors in a digitized audio signal transmission system. An analog signal such as an audio signal is sampled and subjected to A/D conversion. The sample word thus obtained is divided into a plurality of symbol elements. Parity words for detecting and correcting code errors are added to every group of a predetermined number of the information symbols through an interleave procedure before being transmitted.

Abstract: Error correction of digital signals is suited for codes having error detection and correction words, such as doubly-encoded Reed-Solomon code. In a first decoding, at least error detection is effected and flags indicating decoding conditions are added. In a second decoding, error detection for first code blocks and error correction for S2 words at unknown locations and E flagged word erasures, where d1 is a Hamming distance and S2 and E satisfy a relation of 2S2+E.ltoreq.d1-1, are parallely or sequentially effected, and a combination of S2 and E having a high correction capability and a low probability of miscorrection is selected from a plurality of correction results of error locations and the numbers of flags added at the first decoding, and the word errors are corrected based on the selected combination.

Abstract: In a stationary head type PCM recorder having an A/D converter for sampling an analog signal and converting the analog signal to a digital signal, a signal processing circuit including data delay means for adding an error detection and correction code and a predetermined signal to the digital signal for each error correction group of a predetermined number of samples, and a multi-track head for recording an output of the signal processing circuit on a plurality of tracks of a magnetic record medium and reproducing the signals recorded on the magnetic record medium; incorrectability of the error detection and correction code for a burst error in the output analog signal due to a burst error in the reproduced output is reduced by delaying parity data by the error detection and correction code and the digital signal data by different delay times such that the digital signal data are dispersely recorded in a track direction and a tape transport direction, and allotting the delayed data to the multi-track head suc

Abstract: The rotating-head PCM record/reproduce apparatus has record and reproduce heads of which the reproduce heads are disposed to scan the recorded track formed by the record heads with a delay of a rotation angle of 90.degree. thereby reading immediately after recording, and circuits for converting analog signal to digital signal, and for compressing the timebase of the digital signal, the compressed digital signal being supplied to the record heads so that no signal is supplied to the record head while the reproduce heads are reading the recorded signal.

Abstract: A rotary-head PCM data recorder in which PCM signals of m in number, a synchronizing signal, control signals related to the PCM signals, and a parity signal for error detection and correction are formed into data blocks, and data blocks of n in number are recorded on one track of a magnetic tape. Among the control signals, bits of signals common to n data blocks (i.e., information needed once for each track) are formed in distributed data allocated in a group of consecutive blocks or tracks, and multiple block distributive control data are recorded on one track multiple number of times, or multiple track distributive control data are recorded along n block strings a multiple number of times. In reproduction, block or track distributive data are composed to reproduce the control signals. The recorder thus arranged reduces the bit number needed for the control signals and compensates dropout of reproduced data due to scratches on the tape and the like.

Abstract: A digital signal recording/reproducing apparatus capable of recording and reproducing digital signals having differences in respect to sampling frequency thereof and the number of quantization bits per sample by means of a common circuit arrangement includes means for varying revolution speed of rotating heads for recording and reproduction or traveling speed of a recording medium as a function of different sampling frequencies. A signal processing circuit for processing the digital signals so as to be suited for the recording on the recording medium is controlled by a clock signal of which frequency is changed in dependence on the different sampling frequencies. The signal processing circuit is arranged so that PCM data contained in a frame is constituted by a number of bits which is equal to a common multiple of the different quantization bit numbers and added with a common frame synchronizing signal and common error detection and correction codes to thereby prepare the PCM signal of the frame arrangement.

Abstract: A digital-to-analog converter device for PCM signals at different sampling frequencies comprises a signal converter which expands the frequency distance between a PCM signal band and a side band by converting the sampling frequencies associated with the PCM signals to be reproduced into higher frequencies. With this signal converter, a single low-pass filter can be simplified, having a gradual ramp cut-off characteristic for removal of the side band wherein a pass band cut-off frequency and a stop band cut-off frequency can be adapted for low pass filtering of the PCM signals at different sampling frequencies.

Abstract: A circuit for reproducing a signal associated with synchronization with a digital data signal. The digital data signal includes a combination of a plurality of pulses each having a predetermined pulse width. The reproducing circuit comprises a logic circuit for discriminating the pulse width of at least one of the plurality of pulses, an oscillator and a frequency divider connected with the oscillator and responsive to the output of the logic circuit to generate a clock signal timed with the output of the logic circuit.

Abstract: In a rotary head type digital information signal recording and reproducing apparatus having plural rotary heads mounted on a rotary drum so as to be capable of recording and reproducing signals on parallel, oblique tracks on a magnetic tape, a tracking signal is recorded on at least one portion of each track which is not overlapped with a portion of each track where a digital information signal is recorded to avoid interference between the tracking signal and information signal. The tape travel speed and the rotary drum rotation speed are changed depending upon the transmission rate for a digital information signal to be recorded and reproduced to make the wavelength of a recorded signal frequency constant irrespective of the signal transmission rate. Tracking control is enhanced without increasing the error rate.