JPS59198511A - Pcm recording system - Google Patents

Abstract

PURPOSE:To attain ease of code error by giving a time difference to a data recorded on each track and an offset to a distance and to attain effectively average value interpolation if the compensation is not possible. CONSTITUTION:After an input signal is converted into a digital signal by an A/ D converter 1 at first, its output is fed to an operating device 2 for data to form a CRCC data and an operating device 3 for compensation track adding a transmitted data at each bit, dividing the result by four and forming the data. Signals are recorded on a tape with minimized time loss by using a multiplex head where a sound recording head for each track is arranged with a tilt. The recorded order is as R1 L1 R2 L2 R3 L3 R4 L4 11, 12 and the data is re corded sequentially from the transmitted order. Further, if it is impossible for the code correction, the mean value interpolation is attained from the data before and after the corresponding data.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PCM recorder, and more particularly to a PCM recorder having a means for compensating for errors during recording using a fixed head and multiple tracks.
Regarding M recorder.

In a PCM recorder using a cassette tape, recording is performed on the tape in the steps shown in FIG. First, the L channel and R channel signals are time-divisionally sampled and then combined. Next, this signal is sequentially A/D converted and the digitized signals, .about.L4 and R1-R4, are stored in a single memory, compensated for code errors by an arithmetic unit, and sent to respective tracks. The PCM signal contains a large amount of information, and in order to record it sequentially on tape, the digitized signal of one channel is divided into several tracks as shown in Figure 2 (in the figure, 4 tracks are used). Track) increases the amount of information per unit time). However, this type of PC
In M recorders, there are many code errors (mainly dropouts) due to dust or scratches on the magnetic tape, which is the recording medium, or uneven rotation of the recorder. Therefore, in order to detect and correct this, CRCC (Cyclic Redundan
There is a method of adding cyCheck Code) and vertical parity to the data. Figure 4 shows the data of each track subjected to this detection and correction means.
Vertical parity is added to each pixel so that the total number of 1f in the N0 column is either an odd number or an even number (in the figure, even numbers are equal). Further, CRCC uses the remainder obtained by dividing one data value of each tractor by 4 as CRCC data.

When providing data with redundancy in this way, if a certain pit drops out, the erroneous part can be detected and corrected from the CRCC and vertical parity.

However, when there are multiple dropouts, CRCC and vertical parity cannot be corrected (even if there are multiple turns, it may not be possible to determine which one is correct even if the calculation is performed. This is a particular problem). This is the case when multiple dropouts occur in the same bit number string, and the case where a large number of dropouts occur consecutively over several tracks. For example, as shown in Fig. 3,
If each second bit of the track Rt drops out, the code error 9 cannot be detected from the CRCC (perpendicular to the CRCC).

The present invention has been made to solve the problem of code errors as described above.) By devising a method of recording data on tape, it is possible to easily compensate for code errors and If this is not possible, average value interpolation can be effectively performed. Figure 4 shows an embodiment of the upper recording method for 10 tracks and 14 bit data according to the present invention. R1,L.

It is recorded in the order of 5RssLs*Rz*L2eR4mL+tct, c2, but at that time each track is temporally
Distance difference? Each track has a 4-bit CRCC. This actually recorded R
Since the length of each data item 1 to L4 is extremely short compared to the track width, one block from %R1 to L4 is extremely long and narrow. Therefore, in order to prevent dropouts of several bits that occur sporadically from concentrating on the same bit number string, it is necessary to make the gap between each data sufficiently wide as shown in Figure 4, and to It needs to be tilted.

In addition, 7C2 of the vertical parity records the remainder number of 4 of the total number of 2-bit 2-tracks (11 of each bit number string), C
Set the RCC to 4 bits (record the remainder of 13 or 15), and record the data of each channel as far apart as possible.

FIG. 5 shows a recording device for obtaining a recording format according to the present invention. First, an input signal is converted into a digital signal by an A/D converter 1, and then the output is converted to a data calculator 2 for creating CRCC data. Then, the sent data is added for each pit, the result is divided by 4, and sent to the compensation track calculation unit 3 that creates data, and then sent to the data calculation unit 2.
From R1 to L4 data including CRCC, and vertical parity 1. from compensation track computing unit 3. C.lambda. is output, and recording is performed on the tape with the recording head of each track being arranged at an angle to minimize time loss. The recording order is R1→L 1-gR
t-+L 2-pRs->L 5-) R4→L 4→t
In E t and C2, calculations and recording are not performed after all data of one block have been collected, but recording is performed sequentially from the data sent.

In the above embodiment, each piece of data was arranged diagonally in a row, but as shown in FIG.
In the other column t1, Rs-Ls-R4y L 4-
(I'z may be recorded respectively to more effectively distribute the proximity data of each channel.

In the present invention, the data is Rs=Lle Rs-Ls
Since adjacent data of each channel is recorded apart from each other like R,,L□R,,L,, a large amount of dropouts occur and code correction becomes impossible. Average value interpolation can be performed entirely from the data. For example, if the data before and after t Rl, R3, the average value R2 is R
t''= (Rt+Rs)/2, the data that caused the error can be replaced with the average value R of the previous and subsequent data R1, R, and average value interpolation can be used effectively. Even if error compensation is performed only by this average value interpolation,
No large error noise occurs. Therefore, for example, as shown in FIG. 7, a code compensation circuit 11 and a 3rd and 5th order interpolation compensation circuit (data estimation by linear prediction) 12 are added to a general PCM cassette recorder 10 to create a PCM cassette recorder 10.
It is also possible to realize a system in which errors due to average value interpolation are compensated for in O.

As described above, according to the present invention, even if dropouts and dropouts occur at the same time at arbitrary times, this dropout does not occur in the same bit number string, so the probability of error υ detection and correction is greatly increased. Become.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of general PCM recording. Fig. 2 is a diagram showing the recording state of conventional multi-track PCM recording, Fig. 3 is a diagram showing an example of each data when vertical parity and CRCC are added in PCM recording, and Fig. 4 is a diagram showing the present invention. FIG. 6 is a diagram showing an embodiment of the recording state of PCM recording according to the present invention. FIG. FIG. 7 is a diagram showing a configuration of an application example of the present invention. 1...A/D converter 2...Data compensator, device 3...Compensation track computing unit Patent applicant Pioneer Corporation] Procedural amendment export ) 1981 Patent Application No. 74324 2, Name of invention PCM recording method 3, Relationship with the case of the person making the amendment Patent applicant address 1-4-1 Meguro, Meguro-ku, Tokyo 153 Name (501) No. ＼Ionia Co., Ltd. 4. In column 1 of the "Detailed Description of the Invention" of the specification to be amended, page 2 of the specification, line 13, "4 Figure 0." will be amended to "3 Figure 3." Above 71

Claims (1)

[Claims] A PCM recording method that expands the time axis of a plurality of PCM signals and records them on a plurality of tracks, the PCM recording method being characterized in that the data recorded on each of the tracks has a time difference and a shift in distance. .