摘要:
A PCM audio signal recording and reproducing apparatus samples an audio signal with a sampling frequency having an asynchronous relation to a field frequency of a video signal; converts it to a PCM signal, adds error detection/correction data to a predetermined number of PCM data, forms a data frame by those signals, modulates it in accordance with a predetermined modulation system, and records the audio signal together with the video signal or just the audio signal on a record medium by using a rotary head type scanner which is controlled so as to have a synchronous relation to the field frequency of the video signal. A digital signal processing circuit having a memory of a predetermined capacity is provided, and the number of digital data to be recorded in one data frame is varied in accordance with a difference between the number of input data of the digital audio signal to the digital signal processing circuit and the number of output data supplied to the record medium for recording. In the recording mode, the PCM audio signal is sectioned into blocks, a data block address signal is added to each block to indicate a relative order of a block to the other blocks and is completely added in one track, certain number of blocks are combined to form a block set for processing signals, and an identification signal completing in the block and an interleave block address signal for indicating a relative order to other blocks are added to each block.
摘要:
In an information recording/reproducing apparatus for recording/reproducing a digital audio signal on/from a magnetic medium, a modulator/demodulator for modulating/demodulating the digital signal by offset quadrature phrase shift keying (O-QPSK). This technique is particularly applicable to the multi-layer recording of video and audio signals in a video tape recording/reproducing system and has the advantage of avoiding interference between the recorded digital audio and video signals at the time of reproduction.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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. The method includes the steps of applying a first frame of symbols, taken one from each input channel, and having a first arrangement state, to a first error-correcting code encoder to generate a series of first parity words; delaying each of the symbols in the first frame and each of the first parity words by a respective different delay time in a unit of the sample word at a delay line to provide a resulting second frame of symbols in a second arrangement state; applying the second frame of symbols to a second error-correcting code encoder to generate a series of second parity words; and transmitting said second frame of symbols together with said second parity words.
摘要:
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.
摘要翻译:数字信号的纠错适用于具有错误检测和纠错字的代码,例如双重编码的里德 - 所罗门码。 在第一解码中,至少进行错误检测,并且添加指示解码条件的标志。 在第二解码中,用于第一代码块的错误检测和未知位置处的S2字的错误检测和E标记的字擦除,其中d1是汉明距离,S2和E满足2S2 + E d1>的关系, 平行或顺序地实现,并且从错误位置的多个校正结果和在第一次解码时添加的标志数量,选择具有高校正能力和低错误概率的S2和E的组合,并且单词错误 根据所选择的组合进行校正。
摘要:
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 such that the data of the adjacent sample points are spaced from each other by at least the distribution length of the parity data and the parity data is arranged between the distributed adjacent data.
摘要:
A signal conversion apparatus for use in a PCM signal processing system in which a series of multi-bit digital signals is produced through sampling and quantization of a multi-channel analog signal. The series of multi-bit digital signals includes groups of multi-bit digital signals being representative of respective analog signal portions constituting the multi-channel analog signal. The apparatus comprises a translating section for producing substitutional multi-bit digital signals from at least one of the groups of digital signals corresponding to at least one analog signal portion, which substitutional digital signals represent amplitudes of the one analog signal portion at sampling points different from those at which the one analog signal was sampled to provide the one group of digital signals. The substitutional digital signals are substituted, in the translating section, for the one group of the digital signals to produce a corresponding group of sampling point-shifted multi-bit digital signals. The resulting PCM multi-bit digital signals are acceptable by digital-to-analog conversion processor requiring PCM digital signals generated through sampling at shifted or different sampling points as compared with the above-mentioned series of digital signals.
摘要:
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. By changing a master clock, which defines the sampling period controlled by the read address, in accordance with the address difference, the difference between the video signal field period and the audio signal sampling period can be controlled and compensated.