Sony Corporation

Tadaaki Yoshinaka

Takao Inoue

Yujiro Ito

Masaaki Hara

Takashi Shimizu

Minoru Kawahara

Toshiaki Noguchi

Tsunenori Shiimoto

Jun Sawai

Tadao Fujita

Teruyuki Yoshida

Fumiaki Henmi

Tetsuo Kani

Nobuchika Momochi

Takashi Sasaya

Kazuo Tomita

Takashi Takayama

Takeo Ooba

Kanji Yamashita

An apparatus for recording information, which comprises a one-dimensional diode array () constituted with a plurality of laser diodes arranged in a line, a modulation control signal generator () for supplying the laser diodes constituting the one-dimensional diode array with modulation control signals based on information to be recorded, and an optical system () for causing laser light beams obtained from the one-dimensional diode array to be incident upon an optical tape (), wherein said optical system is operative to focus the laser light beams which have been modulated in response to the modulation control signals and obtained from the one-dimensional diode array so that geometric optical images of the modulated light beams are reduced over the diffraction limit thereof on the optical tape. Accordingly, when information recording on the optical tape or information reproduction from the optical tape is carried out with the laser light beams incident upon the optical tape, difficulties in determining and maintaining positional relations among various optical means can be reduced and the coefficient of utilization of the laser light beams can be improved.

Apparatus for recording information and apparatus for recording and reproducing information

A digital information reproducing apparatus and method in which a digital reproduction signal is equalized by predetermined equalizing characteristics, and a first clock signal is formed on the basis of the equalized signal. The digital reproduction signal is A/D converted using the first clock signal. A predetermined time base decompression is performed on the A/D converted signal every signal portion by the first clock signal and a second, lower frequency clock signal which is supplied separately from the first clock signal. Decoding data is output by performing a maximum likelihood decoding process to the signal after time base decompression. A predetermined time base compression is performed to the decoding data output by the maximum likelihood decoding process.

Digital information reproducing apparatus and reproducing method

A viterbi decoder employed in a digital-signal playback apparatus provided by the present invention such as a video tape recorder and an optical-disc apparatus executes the steps of carrying out tentative discrimination on an input signal, equalizing the input signal in accordance with a result of the tentative discrimination, limiting the number of state transitions of the equalized signal and forming a judgment to select a most probable state transition among the limited number of state transitions. As a result, the viterbi decoder is suited for viterbi decoding and allows the viterbi decoding to be carried out on a digital signal by using a simple configuration.

Digital-signal playback apparatus

This invention relates to a digital signal reproducing apparatus. This invention is applicable to an apparatus such as a video tape recorder and an optical disk drive, using a Viterbi decoder therein. Noise characteristics are equalized at points of discrimination by adding an equalized signal SPR of a differential system and an equalized signal SPR of an integrating system in a weighted manner, or by adding up metrics Maa-Mbb, (Ma&prime;, Mb&prime;) relative to amplitude reference values calculated for the two equalized signals SPR and SPR over each of relevant paths in a weighted fashion. The arrangements allow the inventive apparatus to avert noise-induced deterioration of discrimination accuracy.

Digital signal reproducing apparatus

This invention relates to a data decoding apparatus and data decoding method which perform maximum likelihood decoding by means of a simple construction, and which can be applied for example to a videotape recorder or optical disk device. In the data decoding apparatus or data decoding method according to this invention, a logic level inversion timing during one clock interval is detected from an input signal, a provisional identification result of identifying the input signal is corrected by effectively one clock identification error, the number of state transitions which can be obtained from the input signal is limited based on this corrected provisional identification result, and the most probable state transition of these limited state transitions is detected to output an input signal identification result. Further, in the data decoding apparatus or data decoding method according to this invention, a provisional identification result is obtained by identifying an input signal by effectively one clock identification error, a logic level inversion interval is corrected when a logic level inversion interval occurs in a shorter interval than a permitted logic level inversion interval in the input signal, the number of state transitions which can be obtained from the input signal is limited based on this corrected provisional identification result, and the most probable state transition of these limited state transitions is detected to output an input signal identification result.

Data decoding apparatus and data decoding method

Error correction processing method and apparatus for digital data

A digital audio and video signal recording system and method wherein erasure of a channel has no major effect on adjoining audio signals in the case of high density recording. The same channel of audio signals are recorded arranged in blocks in a direction orthogonal to the helical track of the magnetic tape. There is a possibility of the occurrence of error at the two outside tracks due to narrowing of the tracks at the time of editing of a channel, but preferably an outer code is added to enable erasure correction.

System and method for recording digital audio signal and digital video

A total of eight magnetic heads are attached to a rotary drum in a manner such that the magnetic heads of four channels are spaced apart from the other magnetic heads of four channels by an interval of 180.degree.. A magnetic tape is wrapped around the peripheral surface of the rotary drum in a range of 270.degree.. The channels are repaired off and time divisionally multiplexed so that four signals are formed. Those signals are subjected to digital recording processes by the circuit blocks. Recording data of eight channels having phases which coincide with the recording phases of magnetic heads is produced by the FIFO memories on the output side.

Apparatus for recording and reproducing a digital/video signal having a

In a picture data recording system, a coding processing unit encodes picture data having a quantity of data generated at a different point in time so that its data quantity becomes equal to a predetermined target data quantity at every predetermined field. An error correcting code adding unit adds known data to the picture data coded by the coding processing unit within a correcting ability range by error correcting codes to carry out a parity calculation so as to add an error correcting code to picture data of a predetermined target data quantity. Thus, a recording unit records, onto a recording medium such as a magnetic tape, etc., the picture data having the predetermined target data quantity to which the error correcting code is added by the error correcting code adding unit. In addition, in a picture data reproducing system, a reproducing unit reproduces picture data from the recording medium. Then, an error correcting processing unit adds known data to the picture data having the predetermined target data quantity obtained from the reproducing unit to implement an error correcting processing thereto on the basis of an error correcting code used in the picture data recording system.

Picture data recording apparatus and picture data reproducing apparatus

In a digital data recording and/or reproducing apparatus, the frequency of digital data to be recorded or that has been reproduced is converted so that data blocks formed from the digital data have a time duration that allows for coordination with the timing of data sectors formed from the data blocks and recorded with predetermined timing in respective tracks on a recording medium.

Digital data recording and/or reproducing apparatus

Time base error correction apparatus for correcting time base fluctuations in input digital signals containing block sync signals includes a clock generator for generating clock signals from the input digital signals that contain the same time base fluctuations. A first FIFO memory for writing and reading out the input digital signals on the basis of the generated clock signals and on the basis of reference clock signals, respectively, corrects the clock phase, and a second FIFO memory controlled during writing on the basis of the block sync signal separated from the output of the first FIFO memory and controlled during readout on the basis of a reference block sync signal corrects phase errors of the block sync signal.

Apparatus for correcting time base fluctuations in digital signals

In a digital video tape recorder designed for recording each unit of video data in a plurality of tracks simultaneously by the use of a plurality of magnetic heads, the shift value between a track scanned by a magnetic head in a reproducing mode and another track recorded previously by the same magnetic head is decided from the majority of shift values obtained with respect to the individual magnetic heads, and the contents of identifying signals included in the pickup data are determined in accordance with the majority-decided shift value, whereby accurate shift values and identifying signals are ensured to consequently realize satisfactory picture reproduction.

Apparatus for reproducing digital data

There is disclosed an automatic phase control apparatus for controlling a phase of a phase information signal used for producing an initial address, the initial address being used for writing into or for reading out from a memory circuit of a time base corrector for reducing a time base error included in a reproduced video signal, including a phase shift circuit for shifting the phase of a horizontal synchronizing pulse, a phase comparator for comparing a phase between the phase shifted horizontal synchronizing pulse and a constant wave signal being in phase with a chroma burst signal and a feedback circuit between the phase comparator and the phase shift circuit for applying a feedback signal in relation to an output signal of the phase comparator to the phase shift circuit so that the phase of the phase information pulse signal is synchronized with the constant wave signal. In this case, the automatic phase control apparatus is characterized by the feedback circuit which includes a capacitor for holding the amplitude of the output signal of the phase comparator, a display circuit connected to the capacitor for indicating the value of the output signal of the phase comparator and a stabilizer circuit connected between the capacitor and a switch circuit for stabilizing the feedback signal so that the value of the feedback signal is approximately zero voltage when the switch circuit is operated.

Automatic phase control circuit used for time base corrector

A read start pulse generator comprises circuit elements for automatically adjusting the phase of a read start pulse signal by cancelling phase offset caused when phase adjustments are made to a synchronizing signal, burst signal, and hue signal.

Read start pulse generator for time base corrector

In a time base corrector for correcting time base fluctuations of signals reproduced from a record medium, on which a plurality of time-compressed component signals occurring within one horizontal period in a predetermined sequential order are recorded in response to a clock signal with a predetermined frequency, a write clock pulse generator used in the time base corrector includes a phase shifter for shifting the phase of an incoming write clock signal, whereby the write clock signal having a frequency different from the predetermined frequency is generated in response to a horizontal synchronizing signal, the start time of each of the plurality of reproduced component signals is detected and the shifting amount of the write clock signal by the phase shifter is switched in accordance with the detected output so as to synchronize the write clock signal with the start time of each of the reproduced component signal.

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Kanagawa, Japan

Tadaaki Yoshinaka