JPH01201874A - Method for recording multi-channel pcm data - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to a multi-channel PC that records multi-channel PCM data on a magnetic tape via a rotating magnetic head.
This relates to an M data recording method.

[Summary of the invention]

The present invention is a method of distributing and recording multi-channel PCM data of more than one channel by using a method of distributing and recording two-channel PCM signals on a magnetic tape, and in which a data string is It is divided into the first system and the second system which are arranged alternately in word units,
Among the PCM input data of channels (k-m + n≧3), data for m channels is sent to the first system, and
The data for the remaining n channels is distributed to the second system, and then the i-th time series data of the a-th channel of the first system is divided into L (a, 1) (1≦a<m), the The first time series data of the b-th channel of the two systems is expressed as R(b,j
) (1≦b≦n), one cycle of the data string of the first system is L (1゜l)L (2+ 1) ・-
--L (m, i)L (m, i +1)...L (2
, i+1)L (1, i+1), and one period of the data string of the second system is H(1, j
)R(2,j)‥‥R(n,j)R(n,j+1)-R
(2,j+1)R(1,j+1) After generating the read data rearranged to become (1, j+1), the read data is regarded as input data of two channels and is distributed and recorded on the magnetic tape. Even if , dropout, etc. occur, error correction can be performed satisfactorily, and the original signal can be restored and reproduced satisfactorily.

[Conventional technology]

In general, in digital audio tape recorders that use PCM signals, when a dropout or burst error occurs due to small scratches or dust on the magnetic tape, the playback waveform of the channel corresponding to the data concentrated at that location is significantly affected. receive. Furthermore, in a rotating magnetic head type PCM data recording/reproducing apparatus, if an abnormality occurs in the head of one track, the channel assigned to that track becomes completely unreproducible.

As a countermeasure against this problem, in a two-channel rotating magnetic head type PCM data recording and reproducing device (for example, Japanese Patent Application Laid-open No. 61-236074), which is a standard audio device, the first
As shown in Figure 1, the even-numbered data string (in units of 1 word) of the L channel in the input data (1) on the temporal series
Ao, A2 + . . . are placed in the first half (2a) of the +azimuth track on the magnetic tape, and the odd-numbered data A1 .
A3 * .... - the second half of the azimuth track (3b
), the even-numbered data of the R channel Bg H82+
... to the first half (3a) of the -azimuth track and odd-numbered data Bl + B3 *... to the second half (2b) of the +azimuth track; A two-channel deinterleaving circuit for performing inverse conversion is provided. As a result, even if an abnormality occurs in which the output of the +azimuth track cannot be obtained, the data of every other two channels can be reproduced from the head of the -azimuth track, and by performing average value interpolation, etc., the original waveform can be reproduced. It is possible to restore and play back a waveform that is close to the original. Note that the input data in Figure 11 (
1) The sampling frequency fs is 48 KHz, the number of 3 quantization bits is 16 bits (1 word), and the data length is 2.
It is 880 words, + the first half of the azimuth track (2a
) and the latter half (2b) each record 720 words of data. Q in the center of the data is a correction code.

(Problem to be solved by the invention) Recently, multi-channel PCM with three or more channels
However, in order to perform multi-channel distributed arrangement, input and output data must be time-divided based on a conventional two-channel recording and reproducing device, as shown in Figure 12. First, a recording/reproducing device that only distributes data to multiple channels can be considered.

In FIG. 12, (4a), (4b),
(4c).

(4d) etc. are input terminals that receive analog input signals such as multi-channels A, B, C, D, etc., and (5) is for switching these input signals at the timing of switching signal a and taking them in in a time-divided manner. , (6) is an A-D converter for obtaining 16-bit input data (1) from the captured analog signal, and (7) is an input switching circuit for obtaining 16-bit input data (1) from the input analog signal. Conventional 2-channel interleaving circuit for proper distribution, (7a)
is a connection terminal for inputting the output to a processing circuit (not shown), (8) is a rotating magnetic head connected to the processing circuit (not shown), and (9) is a magnetic tape, which connects the PCM data recording section. is configured.

Furthermore, (10a) is a connection terminal for inputting the output of the processing circuit, and (lO) is a connection terminal that performs inverse Q> conversion on the signal obtained from the rotating magnetic head (8) with the two-channel interleaving circuit (7). Conventional two-channel deinterleaving circuit to obtain playback data (11), (12) is playback data (12)
A D-A converter that converts the signal into an analog signal, (13) is the D
- The output of the A converter (12) is switched to each channel A, B, and C at the timing of the switching signal a.

A switching circuit for outputting images into D, etc. (14a).

(14b), (14c), (14d), etc. are output terminals corresponding to each channel, and these and the rotating magnetic head (8) and magnetic tape (9) connect the PC
An M data reproducing section is configured.

In the above, if the input switching circuit (5) takes in input signals of three channels in which the i-th time series data is A it B it C1, as shown in FIG. 5A, Channel A at sampling frequency fs
(band f s /2), channel B.

C is taken in at a sampling frequency of fs/2 (bandwidth fs/4), and the switching signal a of the switching circuit (5) is driven at a frequency of 2fs.

In a multi-channel PCM data recording/reproducing device using this conventional method with three or more channels, only distributed arrangement is performed for two channels, so data of the same channel may be arranged only on the same trunk, or,
For example, it is concentrated only in the first half or the second half of the trunk,
The degree of dispersion was not appropriate for multiple channels.

For example, when three channels of input data are recorded using a conventional device, the recorded data is placed in the latter half (2b) of the +azimuth track as shown in Figure 5A.
o, C1, C2, .
o*Bt+B2*... are arranged in a concentrated manner. Similarly, Figure 6A shows the recorded data using the conventional method when the human data is 4, 5, 6, 7 and 8 channels.
, Fig. 7A, Fig. 8A, Fig. 9A, and Fig. 10A. Therefore, if a dropout occurs, there is a disadvantage that the channel recorded on the trunk where the dropout occurred will not be reproduced properly.

The present invention has been made in view of these problems,
The purpose of this method is to record multi-channel input data in a distributed manner using a method in which two channels of input data are distributed and recorded on magnetic tape. The object is to properly distribute and arrange the first and second tracks that are alternately formed on the top.

[Means to solve the problem]

The multi-channel PCM data recording method according to the present invention has a first system (
Fig. 5A,
As shown in Fig. 6A, Fig. 7A, Fig. 8A, Fig. 9A, and Fig. 10A, k channels (k - m + n≧3)
Of the PCM input data (1), the data for n channels is sent to the L system, and the data for the remaining n channels is sent to the R system.
Next, the i-th time series data of the a-th channel of the L system is distributed to L (a, 1) (1≦a≦m), and the i-th time-series data of the b-th channel of the R system is distributed to R. (b.

j) When the husband device is (1≦b≦n), Fig. 5B.

As shown in FIG. 6B, FIG. 7B, FIG. 8B, FIG. 9B, and FIG.
l)L (2,1)----L (m,i)L(m,i
t1) ‥‥L (2, it1)L (1, it1), and one cycle of the data string of R system is R(1,j)R(2,3)‥‥R(n+ j)R(
n, it1) ・---R(2, j+1) R(1, J+
After generating the read data (23) that has been rearranged so that be.

Note that the read data (23) is formed by alternately arranging the L series rearranged data string and the R series rearranged data string for each time series data. is a data string that can be called LR integrated time series data.

[Operation] According to the present invention, when the input signal has three channels, the recorded data on the magnetic tape is $5 as shown in Figure B.
They are distributed in a track (+azimuth track) (2) and a second track (-azimuth track) (3), A,
Each of channels B and C is arranged on different halves of different trunks (for channel A, on the front half (2a) of the + azimuth rack and on the rear half (3b) of the -azimuth trunk). More A.

For each channel B and C, even-numbered data strings (Ao
, A2 , etc.) and the odd data string (
Ar, A3, . . . ) are placed on a different track.

Similarly, even if the input signal is 4 or more channels, for example 4.
5.6.7 and 8 channels, Figure 6B, 7th
As shown in Figure B, Figure 8B, Figure 9B and Figure 10B,
The data of each channel is recorded on different halves of different tracks, and even-numbered data strings and odd-numbered data strings of each channel are recorded on different tracks.

[Example] The following is a first example of the PCM data recording method of the present invention.
This will be explained with reference to the figures or FIG. 1O.

In this figure 1 to figure 10, figure 11 and figure 1
Portions corresponding to those in FIG. 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

First, FIG. 1 shows a multi-channel PCM data recording and reproducing apparatus for using the PCM data recording method of the present invention.
This multi-channel PCM data recording and reproducing device is the 12th
In the conventional multi-channel PCM data recording and reproducing apparatus shown in the figure, input data (1) is arranged between an A-D converter (6) and a two-channel interleaving circuit (7) according to the number of channels. A correspondingly converting pre-interleaving circuit (15) is inserted, and the pre-interleaving circuit (15) is inserted into the reproduced data (11) between the two-channel de-interleaving circuit (10) and the D-A converter (12). A post-deinterleaving circuit (16) that performs the inverse conversion is inserted, and both inserted circuits (15) and (16) form a multi-channel interleaving circuit (17). In this FIG. 1, the other parts are constructed in the same manner as in FIG. 12. Further, as shown in FIG. 2, +azimuth tracks (2) and -azimuth tracks (3) are alternately recorded on the magnetic tape (9).

The pre-interleaving circuit (15) and post-deinterleaving circuit (16) are constructed as shown in FIG.

In this Figure 3, (6a) is an input switching circuit (5
) (Fig. 1) input terminal for inputting the time division signal, (6)
is an A-D converter that obtains 16-bit input data (1),
(20) is a multiplexer that switches and selects input data (1) and reproduction data (11). Here (2
0a) is the input terminal on the input data (1) side, (20b)
is an input terminal on the playback data (11) side, (20c) is an output terminal, and a multiplexer (20) is an input terminal on the input terminal (20c).
The data of either a) or (20b) is output to the output terminal (2
0c) side and output.

(21) writes the output data of the multiplexer (20) during the half cycle of the sampling clock b supplied from the outside (b=rOJ), and writes the stored data during the latter half cycle of the sampling clock b ( b=rlJ
).

(22) is a latch circuit that latches the output data of RAM (21) that is output in the second half cycle of sampling clock b, (23) is the read data that is the output of the latch circuit (22), and (24) is the read data. Data (23) is transferred to the 2-channel interleaving circuit (7) side and the D-A converter (12).
This is a multiplexer that outputs signals by switching between the two sides. Here, (24a) is an input terminal into which read data (23) is input, and (24b) is a 2-channel interleaving circuit (7).
The side output terminal (24c) is the output terminal of the DA converter (12), and the multiplexer (24) is the input terminal (24c).
Output the data of 24a) to the terminal (24b) or (24c)
Selectively output to either. In addition, (24) is a 172 frequency divider that divides the sampling clock b into 1/2, (2
6) counts the output of the 1/2 frequency divider (25) and stores it in the RAM (
21) A hexadecimal or 32-decimal counter that generates the write address (counter address A), (27) controls switching between the counter address A and the input switching circuit (5) (Fig. 1). Channel number switching signal a and RAM
Address for reading (21) (encode address E)
(29) is an address switch that switches between counter address A and encode address E at the change point of sampling clock b to generate a RAM address (28) for writing or reading from RAM (21). It is.

Here, (29a) is an input terminal to which counter address A is input, (29b) is an input terminal to which encode address E is input, (29c) is an output terminal, and address switch (29) is connected to sampling clock b. rOJ
When the sampling clock is 0, the input terminal (29a) is selected, and when the sampling clock is rlJO, the input terminal (29b) is selected. In addition, (25b) and (27b) are input terminals for sampling clock b and channel number switching signal a, respectively, and (1
2a) is a connection terminal with the output switching circuit (13) (Fig. 1).

In the above, when the input/output signal is 3 or 4 channels, the counter (26) is in hexadecimal, and the input/output signal is 5,
In the case of 6 or 8 channels, the counter (26) is in 32-decimal notation.

In FIG. 3, when the multiplexer (20) is selected to the input terminal (20a) side and the multiplexer (24) is selected to the output terminal (24b) side, the multi-channel interleaving circuit (17) of FIG. It operates as a pre-interleave circuit (15) and records PCM signals.
Multiplexer (20).

(24) is set to the input terminal (20b) and output terminal (24c), respectively, the multi-channel interleaving circuit (17) becomes the post-deinterleaving circuit (1) shown in FIG.
6), and the PCM signal is reproduced.

Next, the operation of this embodiment will be explained for the cases where the number of channels of the human output signal is 3.4, 5°6.7, and 8.

- In the case of 3 channels - As shown in Figure 5A, the data strings are arranged alternately in word units, and are divided into the A, B, and R channels.
Within the 3-channel PCM manual data (1), 1 channel's worth of data is distributed to the L system, and the remaining 2 channels' worth of data is distributed to the R system, and 1 channel of this L system (
A channel) X-th time series data Ax is L(1,
X), the X-th time series data Bx of the first channel (B channel) of the R system is R (1,
When there is a husband device with R(2,x), one cycle of the data string of R system is R(1,x)R(2,x
)R(2,x+1)R(1°x+1) to generate the readout data (23) of the LR integrated gold time series data.

As for the L system, there is no need to rearrange it because there is only one channel's worth of data. Specifically, the rearrangement is performed using the following steps.

First, in FIG. 3, in order to record a PCM signal, select the multiplexer (20) to the input terminal (20a), and select the multiplexer (24) to the output terminal (24b).
) side to convert the circuit into a pre-interleaved circuit (15)
(Figure 1).

At this time, the signal waveforms of each part in Fig. 3 become as shown in Fig. 4, but the sampling frequency [3 to 41
If the frequency is 3KHz, the switching signal a is 2fs (96KHz
), and the frequency of sampling clock b is also 2fs.
is set to .

At this time, the first half Tl of one period T of the sampling clock b
(b=rOJ) (Figure 4B), input data (1) is written to the address of RAM (21) determined by counter address A, and in the second half 1-2, input data (1) is written to the address of RAM (21) determined by encode address E. The data stored starting from the address is output and becomes read data (28) by the latch circuit (22).

A-D weird Ij! ! A buffer is attached to the device (6) so that it is in a high output resistance state in the read cycle 1.2.

Here, the encoded address table of the address generation encoder (27) in FIG. 3 is shown in Table 1.

Table 1 Counter address A in Table 1 is a hexadecimal counter (26)
is the count value itself, and the encoded address El, E
2 indicates the address to be read, but when counter address A is in area AI (address φ~7), reading is from area A.
2 (addresses 8 to 15), and when counter address A is in area A2, the data in area A1 is read out with the arrangement changed. Using the encoded address El in Table 1,
One period rAj+B 1 of 3 channels shown in FIG. 5A
1Aj◆1+ uiJ (J-21) human power data (
1), array conversion is performed with 8 words as one block, and one period shown in FIG. 5B is rA j * B s r
AJ◆1゜Cs + A s◆21 C4◆1. Aj◆
31 Bt◆1” read data (23) is generated.

Note that here j=2i±1. It is also possible to set it to ±2 etc. This is (Bl *
The data pairs CI ) + (B3 *C3), ... are exchanged, and this read data (2
3) to the 2-channel interleaving circuit, +
In the azimuth track (2) and the azimuth track (3), the data of each channel A, B, and C are recorded on different halves of different tracks as shown in FIG. The second data string is recorded on a different track. Therefore, even if one of the playback RADs fails and the signal cannot be played back, the data of each channel can be played back every other channel, and even if a dropout occurs at a certain location on the tape, the track Different half of the signal can be reproduced, and a waveform close to the original signal can be restored.

Also, as the encode address E, for example, E2 in Table 1
It can be seen that even when using , the data of each channel is still appropriately distributed.

Next, when reproducing a PCM signal, the multiplexer (20) in FIG. 3 selects the input terminal (20b) side, the multiplexer (24) selects the output terminal (24c) side, and the address generation encoder ( 27), simply replace E and A in the encoded address table.

- In the case of 4 channels - As shown in Figure 6A, data for 2 channels out of 4 channels of PCM input data (1) is transferred to the L system, and
The data for the remaining two channels is distributed to the R system.
channel), the X-th time series data C× of L(2, x
), the X-th time series data Bx of the first channel (B channel) of the R system is R (1, x), the second channel (
D channel) X-th time series data Dx of R(2,
x) and a husband device, one period of data string of L system is L (1,X) L(2+ ”) L (
2+ x + 1) L (1+ x+1), and one cycle of the data string of R system is R(
1,x)R(2,x)R(2,x+1)R(1,x+1
) to generate read data (23) of 8 words in one block as an LR integrated time series.

Specifically, the input data (1) is one period rAi, Bi, Cis Di J as shown in FIG. 6, and by changing the encode address table 1, it can be converted into one block as shown in FIG. One cycle rAi with 8 words.

Bi lC3+ Di t Ct◆1, DB◆1
*Ai*1 + Bi+Engine" read data (23) is generated for each channel A.

The recording data of B, C, and D are arranged on both the +azimuth track (2) and the -azimuth track (3) and on different halves. Here, read data (23) is human data (1) and data pair (Ax * C1) (Bt +Dz
), but in addition, for example, the data pair (Ao, C1) (80.

Appropriate distributed arrangement can also be achieved by exchanging Dl).

- For 5, 6, 7 or 8 channels - If the human signal is 5.
For 6 or 8 channels, the input data is shown in Figure 7A, respectively.
, as shown in FIG. 8A or FIG. 10A, one cycle consists of 8 words. Therefore, the array conversion is performed with 16 words as one block as shown in FIG. 7B, FIG. 8B, or FIG. 10B, respectively, and the counter (26) in FIG. When it is 15, it is RAM (21)
When the counter address A is 16 to 31, data is read from the area of addresses θ to 15 of the RAM (21). The procedure for generating read data (23) is basically the same as in the case of 3 channels, and specific examples of read data (23) are shown in FIGS. 7B, 8B, and 10B. . The arrangement of these input data (1) and read data (23) within one cycle is summarized in Table 2.

Table 2 Next, in the case of the 'l channel, data for channels (A, C, E, G) of the 7 channels of PCM input data (1) is transferred to the L system as shown in Figure A. , and when data for the remaining three channels (B, D, F) is distributed to the R system, one cycle becomes 24 words. A; Te for convenience 4
The counter (26) in Figure 3 is 9, with 8 words as one unit.
The read data (23) is generated so as to be rearranged as hexadecimal as shown in FIG. 9B.

B in Figures 7 to 10 shows the recorded data of the corresponding +azimuth trunk (2) and -azimuth track (3), but in each case, the even-numbered data string and the odd-numbered data string of each channel are shown. Since the data is recorded on a different track from the data stream, even if one of the playback heads fails and the signal cannot be played back, the data of each channel can be played back every other channel, so it is possible to perform average value interpolation, etc. With this method, it is possible to restore and reproduce a waveform close to the original waveform.

Historically, the even-numbered data rows and odd-numbered data rows of each channel are recorded on different halves of the trunk, so dust, scratches, etc. can cause dropouts at certain locations on the tape, making playback impossible. Even if such a situation occurs, the recorded signals on a different half of the track can be reproduced, so a waveform close to the original waveform can still be restored.

In the above embodiment, the number of input/output signals is 3 to 8.
Although an example of channels has been shown, it is clear that the present invention can be similarly applied even if the input/output signals are nine or more channels. Specifically, in the case of two channels, using natural numbers m and n that satisfy k = m + n, data for m channels of PCM input data is transferred to L systems, and the remaining n
Distribute the data for the channels to the R system. Next, the data strings of the L and R systems are each inverted every other period, and then they are arranged alternately in word units to generate read data as LR integrated time series data.

Further, the multi-channel interleaving circuit (17) shown in FIG. 3 is not limited to this, and various modifications are possible.

〔Effect of the invention〕

According to the present invention, read data is generated by rearranging input data in a predetermined order, and the read data is regarded as input data of two channels and distributed arrangement of two channels is performed. Even if there is an error in one of the playback heads or tracks, it is possible to record the even-numbered data string and odd-numbered data string of each channel on different tracks, and it is possible to play back a waveform close to the original signal even if an abnormality occurs in one of the playback heads or tracks. becomes.

Furthermore, since the even-numbered data rows and the odd-numbered data rows of each channel are recorded on different trunks and on different halves, even if data dropouts or burst errors occur in one part of the magnetic tape, they are recorded on different halves. Since this data is reproduced, it is possible to reproduce a waveform close to the original signal.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a multi-channel PCM data recording and reproducing apparatus according to the PCM data recording method of the present invention;
Fig. 2 is a diagram showing the recording state of the magnetic tape, Fig. 3 is a block diagram showing an embodiment of the multi-channel interleaving circuit shown in Fig. 1, and Fig. 4 is a diagram showing the signal waveforms of each part in Fig. 3. , FIG. 5(A) is a diagram showing input data and recorded data according to the conventional method in the case of 3 channels, and FIG. Figures 6 to 10 show recorded data for 4 to 8 channels.
11 is a diagram showing the correspondence between input data and recorded data using the conventional two-channel interleaving method, and FIG. 12 is a diagram corresponding to the multi-channel PCM using the conventional method.
FIG. 1 is a configuration diagram of a data recording/reproducing device. (1) is input data, (2) is +azimuth track,
(3) is a −azimuth track, (5) is an input switching circuit, (7) is a 2-channel interleaving circuit, and (10
) is a 2-channel deinterleaving circuit, (11) is playback data, (13) is an output switching circuit, (15) is a pre-interleaving circuit, (16) is a post-deinterleaving circuit, (20) is a multiplexer, (21) is RAM,
(24) is a multiplexer, (26) is a counter, (2
7) is an address generation encoder.

Claims (1)

[Claims] A data string is divided into a first system and a second system alternately arranged in word units, and k channels (k=m+n≧3
) of the PCM input data is distributed to the first system, the remaining n channels' worth of data is distributed to the second system, and then the i of the a-th channel of the first system is distributed. The th time series data is L (a, i) (1≦a≦m), and the j th time series data of the b channel of the second system is R (b, j) (
1≦b≦n), one period of the data string of the first system is L(1,i)L(2,i)...L(m,i
)L(m,i+1)...L(2,i+1)L(1,i+
1), and one period of the data string of the second system is R(1,j)R(2,j)...R(n
, j) R(n, j+1)...R(2, j+1) R(1,
A multi-channel PCM data recording method characterized in that after generating read data rearranged so that it becomes j+1), the read data is regarded as input data of two channels and is distributed and recorded on a magnetic tape. .