Abstract: A magnetic recording apparatus of a digital picture signal comprising a block segmenting circuit for converting an input digital picture signal into data segmented by blocks composed of a plurality of picture elements, an encoding circuit for compressing and encoding the output data of the block segmenting circuit by blocks, and a channel encoding circuit for channel encoding the encoded output data from the encoding circuit, wherein the output data from the channel encoding circuit is recorded on a magnetic tape by a magnetic head mounted on a rotation drum, and wherein the magnetic recording apparatus of digital picture data is characterized in that the track pitch formed on the magnetic tape by the magnetic head is 5.5 .mu.m or less, the diameter of the rotary drum is 25 mm or less, and the rotating speed of the rotary drum is 150 rps or more, the track length per unit time is set to particular value thereby.

Abstract: Disclosed is a signal compression recording and reproducing method for cases wherein signals of similar frequency ranges occur sequentially. The method compresses a signal to record it without conversion into digital data, and then to reproduce the thus-compressed signal. The signal compression recording method determines a predetermined range, and detects an amplitude of a signal at a starting point, and a continuous period that the amplitude variation quantity from the starting point lasts within the upper and lower deviation limits, thereby recording the amplitude of the signal at the point and the continuous period. The signal reproducing method obtains the amplitude of the next signal and the current signal according to the state value, and reproduces the signal by the equation, ##EQU1## where m=1, 2, 3 . . . , a.sub.m .epsilon.{a.sub.1, a.sub.2, a.sub.3 . . . } (amplitude of the reproduced signal); n.sub.m .epsilon.{n.sub.1, n.sub.2, n.sub.3 . . . } (continuous period of the reproduced signal); N=1, 2 .

Abstract: The present invention relates to a digital image signal recording/reproducing apparatus and the method thereof which can maintain a track spacing whereto a digital image signal is recorded during a long time mode in the same way as in the normal mode when the digital image signal is recorded on the recording medium, so that the crosstalks between channels caused by narrowed channel spacing of a tape can be prevented to thereby obtain an effect of a clear picture without a picture quality degradation.

Abstract: A picture enhancing circuit for a reproduced picture signal includes a field memory and a circuit for writing data into the memory, in which the reproduced picture signal is in the form of sync blocks made up of sync data and picture data. After sync detection is performed, the content of the sync data is reset to zero and written into the memory along with the picture data, and each time the sync data and picture data are read out from the field memory the content of the sync data is updated. The contents of the sync data indicate the number of times that the picture data has been read out from the memory and, thus, its age. This age is used to determine whether the picture data can be used or whether it should be interpolated before use.

Abstract: In a digital recorder, a signal process can be performed on digital audio data track by track or event by event in a recording mode or in a reproducing mode. In the recording/reproducing mode, transfer of digital audio data between a hard disk and respective audio input/output devices is executed in real time under control of a DMA controller and a HD controller. A DSP provided between the DMA controller and the HD controller performs the signal process such as a filtering process on digital audio data (block data) of several samplings in a lump, which are transferred (DMA transfer) in a lump between the buffer and the hard disk.

Abstract: An arrangement (60) for recording an analog signal in a track on a record carrier (82) is provided with an overload detection circuit (78) for detection an overload situation for the analog signal applied to the arrangement. Upon detection of an overload situation, the recording mode is terminated and the record carrier is rewound to the start location of the current recording. Further, the arrangement is provided with a variable attenuator (66). The variable attenuation factor in the attenuator is increased upon detection of the overload situation.

Abstract: An arrangement for reading a digital audio signal from a master medium (7) and storing it in a digital storage medium (10, 90, 90') at a first bit rate in a first step, and for repeatedly reading the digital audio signal from the storage medium and recording the digital audio signal on a recording medium (20') at a second bit rate in a second step. The digital storage medium is adapted to store a digital information signal which is a representation of a first music program (M1) and a digital information signal which is a representation of a second music program (M2). The arrangement (FIG. 1b) is further adapted to repeatedly read the digital information signal representing the first music program from the digital storage medium while reading the digital information signal representing the second music program into the digital storage medium in the second step.

Abstract: Apparatus and method of even harmonic distortion compensation are provided for digital data detection in a disk file. The disk file includes a magneto-resistive (MR) head or other magnetic transducer head and an analog-to-digital converter (ADC) for providing a sampled readback signal. An even harmonic filter is coupled to the ADC for providing a filtered readback signal having only even harmonic components. An adder subtracts the filtered readback signal from the sampled readback signal for providing a compensated output signal. The compensated output signal is applied to a digital channel of the disk file.

Abstract: In the reproduction of a video signal from tape-shaped recording medium on which plural oblique tracks are formed in parallel manner, the signal processing for interpolating the video signal reproduced by a rotary head is suitably switched according to the transport speed of the tape-shaped recording medium. Thus, satisfactory interpolation can be achieved at different transport speeds, and a reproduced image of satisfactory quality can be obtained.

Abstract: A customized album recording system is under the control of a central microprocessor or mini-computer. A master library or storage medium is filled with a repertoire of recorded information items (such as musical selections) which may originate with any suitable source, such as phonograph records, tapes, sound tracks, compact discs, or the like. Each information item is stored in the library under its own address. On read out, an operator keys in the addresses identifying the selected items which are read out of the library medium and stored in a large capacity memory, usually to provide about forty-five minutes of total listening time. Then, all of the music is read out of that large capacity memory and recorded at a high speed onto a suitable album size medium, such as a tape cassette, for example. The source music and the customized album music are usually recorded in an analog form. The music which is processed within the system is in a digital form.

Abstract: A disc recording/reproducing apparatus according to the present invention intermittently records and reproduces compressed digital audio data in normal recording/reproduction. In high-speed dubbing of digital audio data, two of such apparatuses are used, wherein compressed digital audio data is continuously reproduced from a disc for reproduction by the reproduction side apparatus to be directly applied to the recording side apparatus and continuously recorded on a disc for recording. Thus, the compressed high-speed dubbing of the digital audio data can be achieved without increasing a rotation speed of the disc even in high-speed dubbing.

Abstract: In a digital data storage audio tape system having a host device interface unit, a main data buffer manager, a main data buffer, a processor, a data separator, a tape drive unit, and a read/write channel, this invention comprises a formatter providing track construction, encoding and decoding, error correction, and direct memory access of digital data transmitted between the host device unit and the tape drive unit and a frame buffer for buffering digital data for encoding and decoding, and error correction. The formatter is coupled between the main data buffer manager, via a direct memory access channel, and the read/write channel of the tape drive, and further is coupled to the frame buffer. The formatter is coupled to and responsive to instruction control by the processor in conjunction with instruction control of the tape drive unit by the processor.

Abstract: When a video signal is recorded on a magnetic tape (14), a high frequency signal component of data converted by a DCT (discrete cosine transform) converter (3) in a DCT fashion or an outer code is recorded on a recording track at its beginning portion in which a waveform of a reproduced output is considerably deteriorated in amplitude when a reproducing head (15) starts to reproduce the recording track. Also, a low frequency signal component of data converted by the DCT converter (3) in a DCT fashion is recorded on the recording track at its succeeding portion in which the reproducing head (15) can stably reproduce the recording track by a recording head (13).

Abstract: An arrangement (60) for recording an analog signal in a track on a record carrier (82) is provided with an overload detection circuit (78) for detection an overload situation for the analog signal applied to the arrangement. Upon detection of an overload situation, the recording mode is terminated and the record carrier is rewound to the start location of the current recording. Further, the arrangement is provided with a variable attenuator means (66). The attenuation factor in the variable attenuator is increased upon detection of the overload situation.

Abstract: A magnetic recorder/reproducer converts two-channel analog signals into digital signals by a sample-and-hold/A-D converter circuit (3) and controls addresses in a memory circuit (4) by a memory address control circuit (5), to distribute the digital signals into odd sample groups and even sample groups per each channel for arraying the odd sample groups and the even sample groups of the same channel in alternate scanning intervals, thereby to write the same in the memory circuit so that the odd samples and the even samples of the same channel are arrayed in positions separated from each other along the direction of scanning by rotary heads (10, 11). The digital signals thus permutated are modulated by a modulation circuit (7), to be recorded in a magnetic tape by the rotary heads. The digital signals reproduced by the rotary heads are demodulated by a demodulation circuit (14), to be stored in a memory circuit (15).

Abstract: The invention relates generally to media carrying symbols representing digital information, the recovery from media of symbols representing digital information and the establishment of the digital information represented by such symbols. While the present invention has many applications, it is more particularly described in connection with preferred embodiments in which the symbols are recovered from and carried by tape- and disk-based storage media in which the symbols are arranged in spiral, concentric, parallel or linear tracks.

Abstract: A magnetic tape for the recording of digital video signals is constituted by a nonmagnetic base having thereon a magnetic layer of at least one thin magnetic metal film which has an energy product of at least 100 G.cm.Oe, and with the surface roughness of the magnetic tape being at most 0.003 .mu.m in center line average height. Such tape, when used with magnetic heads each having a gap defined between portions of the respective head having a saturation magnetic flux density of at least 14 kG., contribute to the maintenance of an acceptable raw error bit rate below 1.times.10.sup.-4 when recording with a recorded bit area of no more than 1.25 .mu.m.sup.2 /bit.

Abstract: A reproduction equalizer including a linear equalizer for linearly equalizing a source signal read from a recording medium, a nonlinear cancellation means for cancelling intersymbol-interference (ISI) contained in the reproduction signal, a decoder for decoding the ISI free signal to reproduce a digital signal prior to storing into the recording medium and means for automatically calculating and/or updating the ISI data held in the nonlinear cancellation means on the basis for the equalized source signal for each address defined by the reproduced digital signal. The nonlinear cancellation means includes a lookup table storing the ISI data, a circuit for generating an address for reading out the ISI data from the lookup table, and a circuit for subtracting the ISI data read out from the lookup table from the equalized source signal. At an initial stage, the calculation means calculates the ISI data, and in a normal operation mode, the calculated ISI data is used.

Abstract: A scheme has been devised for retrieving audio from a digital audio tape (DAT) that has been used in a device such as a digital audio logger wherein audio is recorded on a intermittent basis. An audio bit map is created on the DAT that represents a record of activity with a "1" bit representing audio and a "0" bit representing absence of audio. The channels of the logger can be searched for a next message or previous message. A predetermined sequence of "1's" and "0's" are used in the search for identifying a message.

Abstract: A digital audio signal reproducing apparatus is adapted for reproducing digital audio data at a constant data rate by reading digital audio signals recorded on a recording medium after bit compression, in which the compressed data are read out from the recording medium and written in the memory when the volume of the non-read-out data in the memory becomes lower than a predetermined volume. The reading out of data from the memory is discontinued when it becomes impossible to write data in the memory in order to establish a standby state by way of performing a memory control. Upon actuation of a pause key, the reading out of data from the memory is discontinued. Upon releasing the actuation of the pause key, the readout operation from the memory is re-initiated.

Abstract: A method for digital magnetic recording and reproducing of video images while compressively encoding video image data to reduce a bit rate includes the steps of forming the compressed data into sync-block units corresponding to minimum units for error-correcting, recording the compressed data as sync block units on a plurality of tracks of a digital magnetic tape, and reproducing a recognizable image corresponding to the video image data from the recorded compressed data. According to one aspect of the method, the sync blocks are arranged so as to be recorded on the plurality of tracks using a line sequential scanning method in the track-traversing direction, and the arranged sync blocks are restored to their original locations during reproduction. A digital magnetic recording and reproducing apparatus suitable for implementing the above method is also disclosed.

Abstract: A digital video recording system for digitizing analog video signals and recording the digital signals on video tape and for reading digital video signals from video tape and producing an analog video signal. The recording system comprises an A/D converter, a data compressor for compressing digital video signals at a data rate of 1/N (N: an integer greater than 1), a selector mechanism for selecting between the compressed digital video signal and a non-compressed digital video signal, and a control mechanism for controlling the system such that recording data for one field, which is normally recorded in M tracks (M: an integer greater than N) in ordinary recording mode, is recorded in about M/N tracks in a long recording mode.

Abstract: A method for the continuous recording of irregularly supplied video signals on a selected video tape in a double deck video cassette recorder comprises the steps of: (a) setting a period of time allowing the video cassette recorder to operate in a recording mode during the period of time; (b) selecting any operable one of the two decks to drive a tape loaded therein in response to a trigger signal initiating the recording operation of the selected deck; (c) registering a reference signal to indicate that the selected deck is operable in the recording mode; (d) holding the selected deck in a stand-by state until another trigger signal is generated after the completion of the recording operation during the period of time; (e) referencing the reference signal in order to determine whether the selected deck remains operable to continuously drive the tape loaded therein when said another trigger signal is generated; (f) selecting the remaining operable deck so as to have the recording operation transferred thereto

Abstract: A digital signal recording and/or reproducing apparatus which converts an input analog signal into a digital signal and records the digital signal on a recording medium, or which reproduces a digital signal recorded on a recording medium and converts the digital signal into an analog signal has an analog signal level controller and a digital signal level controller connected in front of and after an A/D converter or a D/A converter and the digital signal level controller and the analog signal level controller are controlled in correlation with each other, whereby the S/N ratio of a recording signal or a reproducing signal can be improved.

Abstract: A data recording and/or reproducing apparatus records and/or reproduces file data by processing the file data on the unit of a predetermined block length, a data block and information data for identifying the data block on predetermined unit regions. A supplement data is recorded on a region other than the region recorded the file data, the block data and the information data for identifying within the unit regions. Thereby these data are recorded and/or reproduction processed at every predetermined units so that the bit error rate is remarkably improved.

Abstract: A high-definition signal (HD) is separated to prevent the quality of an image from being deteriorated when the high-definition signal is mixed with a standard video signal. A low band signal of the HD signal from a decimation circuit (5) is supplied through a discrete cosine transform circuit (7), a quantizer circuit (8), a variable length coder circuit (9) and an encoder circuit (11) to a recording head (12). A signal from the quantizer circuit (8) is supplied through an inverse quantizer circuit (17) to a subtracter circuit (18). A signal from the discrete cosine transform circuit (7) is supplied to the subtracter circuit (18), thereby forming a difference signal between a decoded signal of the compresses signal and the original signal. This difference signal is supplied through a quantizer circuit (19) a run length coding circuit (20) and a variable length coder circuit (21) to an adder circuit (16).

Abstract: An audio signal recording apparatus and method for recording an video signal (e.g., a half field) and at least four channels of audio signals corresponding to the video signal to a plurality of tracks on a tape. The audio signals are recorded to recording blocks in an audio recording area which are separated from a recording area for the corresponding video signal in accordance with a priority rating. More specifically, the at least four channels of audio signals are divided into groups each having a plurality of channels. The audio signal recording area is divided into a plurality of recording blocks in the longitudinal direction of the tracks and each group of audio data is recorded to one of the audio signal recording blocks. Each group of audio data is assigned a priority rating depending on the importance of the data contained therein. Audio data having a high priority are recorded to blocks that are located further away from the track ends than those for audio data having a low priority.

Abstract: A method can record or reproduce a digital audio signal and a digital video signal simultaneously. An N-bit (N: positive integer) digital audio signal is positioned at a higher bit side and an M-bit (M: positive integer) digital video signal is positioned at a lower bit side so as to form an (N+M)-bit digital signal which is recorded or reproduced in this condition. Since the digital video signal is positioned at the lower bit side, the digital video signal may not affect the reproduced audio signal even if the (N+M)-bit digital signal is processed as the digital audio signal in the reproducing process.

Abstract: The present invention describes an improved RLL channel utilizing a closed-loop clock recovery scheme and a simplified decoding algorithm. (1,7) run-length-limited (RLL) code is used to reduce the magnetic nonlinearity problem posed by prior art PRML systems. In the preferred embodiment of the present invention, the analog data signal amplified, filtered and equalized to approximate an ideal waveform. The signal is then sampled and decoded into binary data. The clock recovery circuit is designed to sample the analog data such that the signal peak lies centered between consecutive sample points. It is thus made possible for the phase error to be extracted from a direct comparison of neighboring sample values. The phase error is then used to adjust the clock signal for the following samples. In the decoding algorithm of the present invention, by making useful approximations, the complexity of the decision functions is reduced, along with the number of required look-ahead samples.

Abstract: A recording/reproducing system for use in a digital audio tape recorder using memory functions and a method thereof which are capable of storing reproduced aural signals in a memory bank, and capable of reading and recording the stored aural signals without the use of an additional DAT system. The system includes a memory section for storing signals that are input to a D/A converter from a digital signal processing section, and a memory controlling section for storing signals that are input to the D/A converter from the memory section, and for reading and applying the signals stored in the memory section to the digital signal processing section. As a result, the system and the method for recording/reproducing can duplicate a tape with one DAT by storing reproduced signals in the memory when the DAT is in are producing mode and reading and recording the stored signals in a tape.

Abstract: In a digital VTR that carries out magnetic recording and reproduction by bit rate reduction coding a digital video signal, a fixed length block is formed by controlling the code amount of a large block including a plurality of small blocks located distant from each other on a screen at the time of recording. The fixed length block is divided into a plurality of recording blocks so that the main components of respective small blocks are included separately on the recording blocks, whereby error correction is applied to form a plurality of error correction blocks. The error correction blocks are rearranged so that recording blocks including the main components of small blocks adjacent on a screen are also adjacent on a recording medium. Thus, the possibility of deviation in the information amount of each large block is suppressed to improve efficiency of bit rate reduction coding, and to obtain a high speed reproduced picture of high quality.

Abstract: A digital video/audio recording and reproducing apparatus comprising a video signal high-efficiency encoder having a variable reduction rate, an audio signal high-efficiency encoder having a variable reduction rate, and a controller for controlling the reduction rates in both of the high-efficiency encoders. The reduction rates in both of the high-efficiency encoders are controlled in such a manner that the sum of the information amount of the video signal and that of the audio signal, after high-efficiency encoding, is maintained constant. When recording multi-channel audio signals, the reduction rates in both of the high-efficiency encoders are controlled according to the number of audio signal channels to be recorded. The high frequency components of the high-efficiency encoded video and audio signals are recorded at the end portions of recording tracks on a magnetic tape, while the low frequency components thereof are recorded in the central portion of the recording tracks.

Abstract: Continuous data is divided into a plurality of portions and then recorded on a recording medium such as a magnetic tape or the like so that, even when a recording medium is exchanged, the divided data thus recorded can be continuously reproduced. During a period in which a recording head is moved to a second recording position after the recording at a first recording position is ended, corresponding data reproduced from a recording medium even when the recording medium is exchanged is written in a memory means in which an input signal applied to an input terminal is written.

Abstract: Digital data is recorded on a magnetic tape by rotary heads. The magnetic tape has a PCM data recording area on which PCM data of a plurality of programs is recorded and sub-code recording areas on which sub-code data is recorded. On the sub-code recording areas of each program, character code data representing the title of the associated program and the like is recorded. On the sub-code recording area of the first program, pack data of a TOC mode is recorded. The pack data of the TOC mode includes character code data, and this character code data includes information recorded on the sub-code recording areas corresponding to all programs. By reproducing the pack data of the TOC mode by the rotary heads, character code data of all programs can be recognized.

Abstract: In an arrangement for reproducing standard analog audio compact cassettes and digital compact cassettes is provided with an analog output terminal (9) for supplying an analog audio signal obtained from reproducing a digital audio signal from a digital compact cassette, or an analog signal from a standard compact cassette. The analog reproducer (28) is coupled to the analog output terminal (9) via an A/D converter (20) and a D/A converter (13). A further measure that can be used separate or in combination with the previous measure, is that a digital output terminal (23) is provided and that the output of the analog reproducer is coupled to the digital output terminal (23) via an A/D converter (13).

Abstract: A noise reduction apparatus wherein a sampled digital data is compared with a first threshold value (t) to average the digital data during a period while the level of low frequency components containing jitter noises is a predetermined threshold level or lower, an averaging operation for the digital data after a predetermined number of sampling points continues if a difference value between previously and presently obtained digital data takes a second threshold value (tp) or lower, the averaged digital data obtained during a predetermined number of rotations of a rotary head is converted into an analog signal, and the analog signal is subtracted from a reproduced signal.

Abstract: A video signal recording apparatus is provided with first and second channels for transmitting an input video signal. The first channel has a line memory for conducting a 1H delay on data and a time-base-extension line memory for conducting time base extension on the data with the 1H delay. The data subjected to the time base extension undergoes D/A conversion to be an output of the first channel. On the other hand, the second channel does not have a line memory for a 1H delay, and the video signal without delay is subjected, to time base extension and undergoes D/A conversion to be an output of the second channel. In the arrangement, odd lines and even lines respectively contained in adjoining two frames in each channel are reversed such that in a certain frame, odd lines of the input video signal are transmitted through the first channel with even lines through the second channel. In the next frame, even lines are transmitted through the first channel with odd lines through the second channel.

Abstract: A digital signal recording apparatus directly receives analog signals and digital signals, the directly received digital signals or the analog signals converted to digital form being selectively recorded on a recording medium. The digital signals for recording are selected on the basis of copy-enable/disenable assigning signals which are contained in the directly received digital signals.

Abstract: In a digital signal magnetic recording/reproducing apparatus, input digital signals of plural channels and a recording current control signal expressing recording current values corresponding to the respective digital signals are time-division mulitplexed and transmitted into a rotary cylinder, and the digital signals and recording current control signal are separated by a circuit built in the rotary cylinder. The recording current for each of the digital signals is controlled depending on the recording current control signal. By time-division multiplexing the input digital signals of plural channels and transmitting the multiplexed signal into the rotary cylinder, the number of channels of the rotary transformer can be reduced. Further, by transmitting the recording current control signal into the rotary cylinder, the recording current of the digitally transmitted signal can be adjusted.

Abstract: An apparatus is described for rearranging the relative positions of data samples of a digital video signal within each field of the video signal, for use in a digital VTR in which alternate samples are separated into two different recording channels to be recorded on different tracks of a recording medium. The apparatus includes an intra-line shuffling circuit and a field memory into which output data from the shuffling circuit are written, such that adjacent samples which are of the same channel and are located mutually adjacent in the same line of the video signal are read out from the memory and recorded on respectively different tracks of the recording medium, thereby ensuring that if a sample is lost due to a read error, the adjacent samples of the same channel will always be available for use in interpolation processing to compensate for the lost sample.

Abstract: A digital audio tape recorder signal processor whose signal processing period is Td performs signal processing for recording 2-channel PCM signals having a sampling frequency of Fs. A circuit is provided for compressing the time-base of 4-channel PCM signals by one-half to form 2-channel time-base-compressed PCM signals in which the first and second channels are time-divided and multiplexed and the third and fourth channels are time-divided and multiplexed, so that when the time-base-compressed PCM signal is supplied to the signal processor, the signal processor is operated with a sampling frequency of 2Fs and the signal processing period is changed to 1/2 Td.

Abstract: A television signal format converter is provided for converting without loss of picture information any high definition television format to or from a given recorder/player format. An interface converts between RGB and luminance/chrominance inputs and between analog and digital inputs. The interface couples a high definition television format to a plurality of pairs of memories. A clock and control circuit controls addressing of the memories for reading and writing so that conversion is performed between a high definition television format and a format required for a given high definition digital video tape recorder or any other comparable recorder.

Abstract: An apparatus and method for encoding data in a text format such as ASCII or EBCDIC on a laser disc or compact disc without affecting the digitized sound by utilizing what is known as the subcode channel of the laser disc or compact disc. By storing text data in the subcode channel region as described herein, it is possible to create subtitles for movies in a number of languages such that the language in which the subtitles appear is user selectable. In this manner, it is possible to create laser discs having subtitle information in, for example, ten languages thereby avoiding the necessity of creating ten separate laser discs, each having a different language used for subtitling.

Abstract: A digital recording apparatus has a transporter and processor. (1). Long play mode: The transporter rotates heads and transports a recording medium at each first speed. The processor converts a first input signal supplied at a normal transfer speed with A/D conversion at a first sampling frequency to generate a first data of a quantization levels, converts the first data to a second data of a quantization levels with a first clock frequency and processes the second data which is supplied to the heads so as to be recorded in the medium. (2). High recording mode: The transporter rotates the heads and transports the medium at each second speed which is N times faster than the first.

Abstract: A digital signal reproducing apparatus for reproducing a digital signal from a recording medium on which a digital signal, including coded address data to identify a data block, is recorded includes a reproducing circuit for reproducing the recorded signal, a memory for storing the reproduced signal, an address extracting circuit for taking out the address data from the reproduced signal, a circuit for forming a reference address from the extracted address data, a comparator for comparing the extracted data and the reference address, and a writing circuit for selectively writing the reproduced signal into the memory in response to the output from the comparator.

Abstract: An automatic equalizer for use with a recording and/or reproducing apparatus or with a communication transmission channel, wherein equalizer parameters are rendered variable and the degree of change of the error rate is extracted to set the parameters to optimum values based on the degree of change of the error rate. Output signal error rates are sequentially detected at a plurality of measurement points corresponding to preset plural characteristic parameters to find a minimum error rate measurement point. An initial parameter setting operation is performed for providing characteristic parameters for this measurement point to the equalizer as the initial parameter.

Abstract: A method of simultaneously recording and reproducing a digital audio signal and a digital video signal for a dynamic picture. A digital signal is recorded and reproduced in N bits (N: integer), and an image area, an audio area and a control area are formed by part of the N bits. Compressed digital video signals for multiple screens forming a dynamic picture are allocated in the image area in each compression reference period. A digital audio signal in each compression reference period is allocated in the audio area in the compression reference period. Data, such as compression information, which concerns a digital signal to be allocated in the image area or audio area, is allocated in the control area. As a digital video signal carrying a vast amount of information is recorded in a compressed manner, and the compression information is recorded at the same time, recording and reproducing the digital video signal for a dynamic picture can be executed without problems.

Abstract: There are provided an error correction circuit for correcting a code error of a compressed information code train having been reproduced from a recording medium, compressed in information amount by compression encoding, and added with an error correction code, by using the error correction code, an expansion circuit for subjecting the compressed information code train outputted from the error correction circuit to decoding corresponding to the compression encoding, and expanding the information amount of the decoded code train, an error concealment circuit for concealing an information code of the information code train outputted from the expansion circuit, by using correlation of the information, the information code being unable to be corrected, and a compression circuit for compression encoding again an information code train outputted from the error concealment circuit.

Abstract: A digital signal reproducing apparatus includes an address continuity check circuit, in addition to a parity check circuit, to check the validity of a reproduced block address. The address continuity check circuit checks the address continuity of n consecutively reproduced data blocks. In accordance with the present invention, a reproduced block address will be accepted as a correct block address only when it passes a parity check and a continuity check. Thus, the possibility of failing to detect an incorrect block address is greatly decreased.

Abstract: A voice signal is modulated using two carriers which are perpendicular to each other. The modulated signal is supplied to a low-pass filter, and then sampled. The sampled data are encoded, and then stored. When the stored data are to be reproduced, the data are decoded, and sampled. The sampled data are supplied to a demodulator through a low-pass filter.