JPH04146575A - Digital signal recorder - Google Patents

Abstract

PURPOSE:To reduce the cost of a digital signal recorder by recording the digital signals after coding them into the samples of even and odd Nos with use of the 1st and 2nd record processing means and at the same time recording the 1st and 2nd specific patterns which are substantially coded in the unused areas equivalent to a single channel. CONSTITUTION:The codes are completed to the PCM voice signals of N channels for each signal of N/M (N>=M>1) channels, and only the N/M channels are coded out of the N channels which are used for recording only N/M channels. Meanwhile the specific patterns are selectively recorded in the unused areas equivalent to the channels except other N/M channels. Thus it is possible to reduce the load of a coder, to decrease the circuits, and to reduce the cost for an N/M channel recorder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital signal recording device that can record digital signals at low cost.

[Conventional technology]

For high-visibility television, a four-channel stereo broadcast called the 3-1 system (three front channels, one rear channel) is being considered to accommodate high-definition, high-presence video.

Therefore, in a VTR that records high-definition broadcasting, it is necessary to record four channels of audio signals. Figure 4 shows the literature [New Hi-Visin VTR - Upper inch cassette type UNIHI -] (NHK Giken R&D 臘619
FIG. 2 is a trunk pattern diagram including an image of a conventional digital signal recording device disclosed in August 1989 (P, P, 24 to P, P, 33).

In this FIG. 4, 101 is a magnetic tape, arrow 102
indicates the tape running direction, arrow 103 indicates the head running direction, 10
4,105 is a video signal. Two adjacent tracks are simultaneously recorded and reproduced in one scan by two heads provided very close to each other on the drum.

The audio signal for 4 channels is the PCM audio signal # in Figure 4.
1. Each track is recorded in area #2 so that signals for two channels are accommodated.

Encoding of the PCM audio signal that is simultaneously recorded and played back,
If decoding is to be processed in a time-division manner using one encoder or demultiplexer, fairly high-speed node hardware is required, so two encoders are generally used.

It has a decoder and processes in parallel.

[Problems to be Solved by the Invention] The conventional track pattern is as described above. However, since the system configuration of conventional general audio equipment supports two-channel stereo broadcasting,
Although standards have been prepared for high-definition television VTRs and the like that can record and play back four channels of PCM signals, a low-cost VTR that can record and play back only two channels of PCM audio is required.

In this case, with conventional equipment, only two channels of PCM
Even devices that record and reproduce signals need to perform the same encoding and decoding processes as those that support 4 channels.
The problem was that lower prices could not be achieved.

This invention was made to solve the above-mentioned problems, and utilizes the standard determined to record and play back N-channel PCM audio signals.
) It is an object of the present invention to provide a digital signal recording device which can record and reproduce only PCM audio signals of a channel, reduce the number of encoding/decoding circuits, and reduce the cost.

[Means to solve the problem]

The digital signal recording device according to the present invention records even-numbered sampled samples within a predetermined unit time of sampled PCM signals of N/M (N≧M〉1) channels among N channels. The first part of the recording medium is marked with
When recording in a predetermined area, a first specific pattern similar to that encoded by the encoder is selectively recorded in an area for unused channels other than N/M channels. and a processing means, when recording odd-numbered samples within a predetermined unit time of the N/M channel sampled PCM signals in a second predetermined area of the recording medium; In the area for the above-mentioned unused channels, there is a second
A second processing means for selectively recording a specific pattern is provided.

[For production]

The first recording processing means in the present invention encodes and records even-numbered samples of N/M channels in a first predetermined area of the recording medium, and encodes and records the encoded samples in an area for one unused channel. The first similar to
A second recording processing means records the odd-numbered samples of N/M channels in a second predetermined area of the recording medium, and records them in an area for unused channels. A second specific pattern similar to that encoded is recorded.

〔Example〕

Next, an embodiment of the digital signal recording apparatus of the present invention will be described with reference to the drawings, but in order to facilitate understanding of the present invention, the PCM signal recording format will first be explained using FIG. 2.

This FIG. 2 is a track pattern showing only the PCM signal areas of two adjacent tracks. In this figure 2,
PCM audio signals for four channels, channels 1 to 4 (hereinafter referred to as "ch") sampled or input within a predetermined unit time (for example, l field period), are sampled or input in the order of sampling or input within the unit time. The samples are separated into even-numbered samples and odd-numbered samples according to ch, 1. ch, the even numbered sample of 2 is #
The odd-numbered samples of ch,1 and ch,2 are placed in the first half of the #2 trunk, and the odd samples of ch,1 and ch,2 are placed in the second half of the #2 trunk.
The even-numbered samples of 3, ch, and 4 are in the first half of #2 track, and the odd-numbered samples of ch, 3, ch, and 4 are in the first half of #2 track.
It is recorded in the second half of one track.

Here, the reason why even and odd samples of the same channel are separated in the longitudinal direction of different trunks is to improve the ability to correct head clogging and burst errors.

The error correction codes are ch, 1 and ch, 2, ch, 3 and ch,
The codes for ch, 1 and ch, 2 are generated in the area Q12.
The codes for ch, 3 and ch, 4 are recorded in area Q34.

When recording and reproducing only two channels using the above-mentioned format for recording four-channel PCM audio signals, only ch.1 and ch.2 are used, for example.

The track pattern at this time is shown in FIG.

Here, the areas indicated by a and b are not used.

Next, the configuration of the digital signal recording apparatus according to the present invention will be explained using the block diagram of FIG. In FIG. 1, 11 and 12 are two-channel analog audio signal input terminals, and these analog signal input terminals 11.1
The analog signals input to 2 are input to analog-to-digital converters (hereinafter referred to as ADCs) 21 and 22, and after being converted to digital signals, they are respectively stored in memories 31 and 3.
2 is set to be input.

Further, 40 is an encoder (hereinafter referred to as ENC), to which the stored contents of the memory 31.32 are sent, an error correction code is generated, and the code is stored again in the memory 31.32.

Further, the signal of the memory 31 and the output of the pattern generation circuit 51, and the signal of the memory 32 and the output of the pattern generation circuit 52 are selected by signal selection circuits 61 and 62, respectively.

The outputs of the signal selection circuits 61 and 62 are sent to digital modulation circuits 71 and 72, respectively.
The outputs of 1.72 are output to heads 91.92 via recording amplifiers 81.82, respectively.

The signal selection circuit 61, pattern generation circuit 51, digital modulation circuit 71, recording amplifier 81, and head 91 constitute a first processing means, and the pattern generation circuit 52, signal selection circuit 62, and digital modulation circuit also constitute a first processing means. circuit 7
2, recording amplifier 82, and head 92 constitute a second processing means.

Next, the operation will be explained. Analog signal input terminal 11
．． Analog audio signals of channels 1 and 2 inputted to channel 12 are sampled by ADC 21 and ADC 22, and converted into PCM signals.

ch, 1. The even-numbered samples within a unit time of the PCM signal of ch, 2 are stored in the memory 31, and the odd-numbered samples are stored in the memory 32.

After this, the samples stored in the two memories 31 and 32 are read out in a predetermined order and sent to the ENC 40,
In the ENC 40, an error correction code is generated and stored in the memory 31.
and stored.

When the encoding in the ENC 40 is completed, the signals in the memory 31 and the memory 32 are read out, but at this time, the signals from the memories 31 and 32 and the pattern generation circuit are sent to the digital modulation circuits 71 and 72, respectively. Signals from 51 and 52 are selectively supplied by selection circuits 61 and 62, respectively.

That is, in the pattern generation circuit 51, 391 in FIG.
The pattern generation circuit 52 generates a signal in the bsJl region shown in FIG. That is, each pattern generation circuit 51, 52 generates a specific pattern similar to that coded by encoder 40.

The selection circuits 61 and 62 are controlled to switch signals from the memory 31.32 and the pattern generation circuit 51.52 so that a track pattern as shown in FIG. 3 is formed for each track.

The signals selected by the selection circuits 61 and 62 are digitally modulated by digital modulation circuits 71 and 72, respectively.
Heads 91 .
The information is recorded on the recording medium in step 92.

Here, the following patterns are considered to be generated by the pattern generation circuits 51 and 52.

(11ch h, 3 and ch, 4 audio signals are digitally muted, that is, digitally "0")
(generally the code is also "0")
”).

+21 ch, 3 and ch, 4 audio signals are “0”
A pattern encoded as a constant value other than ''.

It is.

In the above explanation, the signals from the pattern generation circuits 51 and 52 are digitally modulated by the digital modulation circuits 71 and 72, but if the pattern after modulation by the digital modulation circuits 71 and 72 is fixed, A configuration may be adopted in which this modulated pattern is generated.

Further, the formant to which this invention is applied is not limited to the one shown in FIG. 2, and it is clear that the arrangement of data is not particularly limited as long as it is encoded every 2 channels.

〔Effect of the invention〕

As described above, according to the present invention, an N-channel PC
For M audio signals, the code is completed for each signal of N/M (N>M>1> channels, and only N/M channels of the N channels used when recording only N/M channels are encoded. , a specific pattern is selectively recorded in the area for unused channels other than other N/M channels, so the N/M channel recorder reduces the burden on the encoder and saves time on its circuit. This has the effect of being suitable for lowering prices since it can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital signal recording device according to an embodiment of the present invention, and FIG. 2 is a PCM applied to the same device.
FIG. 3 is a diagram of a track pattern of an audio signal, FIG. 3 is a diagram of a two-channel track pattern recorded by the same device, and FIG. 4 is a diagram of a track pattern including an image of a conventional digital signal recording device. 21.22...Analog-digital converter, 3
1.32...Memory, 40...Encoder, 51.52
...Pattern generation circuit, 61.62...Signal selection circuit, 71.72...Digital modulation circuit, 91.92
···head. Agent Masuo Oiwa Figure 4

Claims (1)

[Claims] a first memory for storing even-numbered samples within a predetermined unit time of sampled PCM signals of N/M (N≧M>1) channels among the N channels; a second memory for storing odd-numbered samples within a predetermined unit time of the N/M channel sampled PCM signals;
an encoder that reads samples stored in a memory in a predetermined order to generate an error correction code and stores it in the first and second memories; A first specific pattern similar to that encoded by the encoder is selectively stored in a predetermined area of the encoder, and a first specific pattern similar to that encoded by the encoder is selectively stored in an area for unused channels other than the N/M channels among the N channels. A first processing means for performing a recording process, and storing the stored contents of the second memory in a second predetermined area of the recording medium, and storing the data encoded by the encoder in the area for the unused channels. and second processing means for selectively recording and processing a second specific pattern similar to the above.