Abstract: A magnetic recording and reproducing apparatus capable of recording video, audio and other information on a magnetic tape by, for example, the helical scanning method. A rotary head is rotated at an m-fold speed to record intermittent tracks on the magnetic tape so that real-time simultaneous monitoring is performed. By high-speed dubbing due to high-density intermittent recording and by increasing the number of repetition of track scanning, the information is recorded and reproduced simultaneously with a plurality of channels. Any tracking error is detected to form a continuous and uniform track pattern. With this intermittent comb-shaped recording, reciprocating recording and reproducing can be realized.

Abstract: In a high-efficiency encoder which performs motion-compensation prediction, an intra-field is set every n fields. The presence of a scene change is detected. When a scene change occurs, a reference picture of motion-compensation prediction is switched, or the field immediately after the scene change is set as an intra-field.

Abstract: A high-efficient coding apparatus and method for compressing a digital video signal such as a color television signal, by dividing the digital video signal into a plurality of sub-bands, formatting the video signal of each sub-band into blocks per every plurality of picture elements, performing an orthogonal transform to each formatted block and coding coefficients obtained by the orthogonal transform.

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: A coding apparatus reduces a digital image signal. The coding apparatus includes a block formatting circuit for dividing the digital image signal into blocks of a plurality of picture elements, an orthogonal transforming circuit for transforming the blocks of plurality of picture elements into a plurality of coefficients, an adaptive quantizing unit for quantizing the plurality of coefficients with a quantization table, a calculating circuit that divides each block of the digital image signal into a plurality of sub-blocks and obtains a plurality of indexes, and a detecting circuit that obtains a maximum index and a minimum index from the plurality of indexes. Each index indicates a degree of change between the picture elements in a sub-block of the plurality of sub-blocks.

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), an encoding and modulating mechanism that provides digital data segments, 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 digital VTR is provided for recording data for one-frame of video and audio signals, which have been error-correcting-encoded collectively, in a predetermined number of pieces of tracks during normal recording and for recording data for the video and audio signals, which have been error-correcting-encoded collectively, in one less than the predetermined number of tracks and data for the audio signal, which have been error-correcting-encoded during post-scoring, in the remaining one track exclusively for the post-scoring during post-scoring audio recording.

Abstract: Specified modular arithmetic is applied to input digital data to divide the input data into two main codes and a subcode. Otherwise, input digital data is divided into two pieces of digital data according to a specified rule. The digital data is divided so that the original input digital data can be completely restored if the two main codes and the subcode or both of the divided data are used, and the original input digital data can be nearly correctly restored even when one of the main codes or one of the divided data is used.

Abstract: A digital video tape recorder has interpolation and crossfading circuits and records audio and video signals in independent frames, the audio frames being offset with respect to the video frames. For a four-channel audio signal, the even and odd samples are recorded near different edges of the tape, enabling burst errors near one edge to be recovered efficiently by Interpolating the audio signal from the other edge. When audio dubbing is performed, the first and last dubbed frames contain the even samples of the new signal and the odd samples of the old signal, or vice versa, and audio-dubbing flags are recorded in the these frames. When these frames are played back, the old and new signals are regenerated by interpolation and crossfaded to create a smooth transition between them. The same apparatus can also be used to record a two-channel signal, by recording each sample twice.

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 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: A coding apparatus, in which each block having a plurality of picture elements with digital image signals is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in the sub-block, so that a digital image signal is reduced. Moreover, a coding apparatus, in which each block having a plurality of picture elements with digital image signals is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the maximum and minimum values of the image signals of the picture elements in the sub-block, so that a digital image signal is reduced.

Abstract: A coding apparatus, in which each block having a plurality of picture elements with digital image signals is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the absolute value sum of difference of image signal level between adjacent picture elements in the sub-block, so that a digital image signal is reduced. Moreover, a coding apparatus, in which each block having a plurality of picture elements with digital image signals is divided into a plurality of sub-blocks, and an appropriate quantization step or weighting factor is decided on the basis of the maximum and minimum values of the image signals of the picture elements in the sub-block, so that a digital image signal is reduced.

Abstract: A pulse code modulation (PCM) recording and reproducing apparatus for recording analog signals from N channels which are sampled at a predetermined sampling frequency and converted into samples of a variable number of bits each. The samples of PCM data are assembled into a frame consisting of a specific number of samples and the frames are assembled into a number of blocks of PCM data comprising a specific number of tracks. The number of bits per frame is set to a value equal to the least common multiple of all values of bit quantization numbers which the samples may have such that digital signal sources of varying bit quantization formats may be accomodated by the recording apparatus utilizing a simplified structure.

Abstract: A digital signal reproducing apparatus reproduces coded digital signal data which have been recorded on a magnetic tape. The digital signal reproducing apparatus includes first and second decoders. These decoders perform the error correction and erasure correction. The second decoder has a higher error detection capability than that of the first decoder. The reproducing apparatus further includes a checking circuit for checking code errors contained in the coded digital signal data. When the code errors detected by the checking circuit may occur simultaneously, a first editing-point detection signal is produced. When the first editing-point detection signal is output, a judgement is done that the editing-point may exist in the digital signal data, and the first decoder is changed to the second decoder for a predetermined time period. When the second decoder detects correction-prohibited data portion, a second editing-point detection signal.

Abstract: A decoder for decoding a code C which is two-stage encoded by a C.sub.1 code ((N, K, D) Q dimensional code) and a C.sub.2 code ((n, k, d) q dimensional code), which includes: a C.sub.1 decoder including an error correction means for conducting an error correction of the errors below the number [(D-1)/2] to output the decoded word, and a weight generator which generates wj (j=1, 2, . . . , n) when i (i=0 to [(D-1)/2 ]) errors are corrected and an error detection (correction disability) is judged; a C.sub.2 decoder for decoding the C.sub.2 code including a forfeiture error correction means for judging the position j of the wj among the weight vector w in the received word r which is obtained in accordance with the decoded word output from the C.sub.1 decoder, and conducting a forfeiture error decoding. A weighted distance calculating means for calculating the weighted distance .rho..sup.(k) between the decoded word r.sup.(k) and the received word r when a decoded word in each of K=0, 1, . . .

Abstract: An error correcting and controlling system forms syndromes S.sub.1 and S.sub.2 for each of a set of reproduced, sampled signal words and error correcting words P or Q and also forms a syndrome S.sub.i =S.sub.1 .sym.T.sup.i-7 S.sub.2 by using the result of a CRC check of the set of sampled signal words. An error position i is determined by three zero counters which respectively indicate S.sub.1 .noteq.0, S.sub.2 .noteq.0 and S.sub.i .noteq.0. Alternatively, the system may further include three counters for respectively counting errors developed in the set of sampled signal words, and the error correcting words P and Q, the errors being detected by a CRC check circuit. When any one of the counters counts an error and the remaining counters count no error with S.sub.1 .noteq.0, S.sub.2 .noteq.0 and S.sub.i .noteq.0, a control signal is generated to perform a concealing operation, such as a means value interpolation, etc.

Abstract: A PCM record reproducer comprises a coder circuit for forming PCM signals by adding error detection codes to data signals in a predetermined pattern; a splice detection circuit for determining a splice point of a magnetic tape by finding inconsistency of the detected result of said error detection code depending upon said PCM signals read-out from said magnetic tape in which said PCM signals are recorded; and an editing circuit for editing said PCM signals when the splice point is determined by said splice detector circuit.

Abstract: An apparatus for reproducing voice signals from a PCM magnetic recording tape which is equipped with a discontinue waveform calibrator which comprises a control signal generator for detecting an edited part from PCM signal rows reproduced from the magnetic tape and for transmitting a control signal; a first memorizing means for memorizing at least one word part of the PCM signal rows which are sequentially imputted; a second memorizing means for memorizing specific words of the PCM signal rows overflowed from the first memorizing means; a third memorizing means for memorizing at least one word part of the PCM signal rows overflowed from the memorizing means; a first weighing means for multiplying a gradually increasing weight from X0 to X1 to the memorized data of the first memorizing means upon receiving the control signal to output it; a second weighing means for multiplying a gradually decreasing weight from X1 to X0 to the memorized data of the third memorizing means upon receiving the control signal; an

Abstract: Upon reproducing a PCM audio signal, the disclosed weighting circuit gradually changes the weight or value of signal bits constituting the PCM audio signal in accordance with a command signal so as to vary gradually a level of a reproduced analog audio signal corresponding to the PCM audio signal.