JPH0142068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PCM recording and reproducing apparatus in which a channel mode signal indicating the number of channels is added to a data signal.

In multi-channel PCM recording and playback, data signals obtained through analog measurement are sent through a multiplexer to an A-D converter, where they are sequentially converted into digital codes and serially recorded on a recording medium such as a magnetic tape. Therefore, during reproduction, this serial data must be reproduced with the same number of channels as during recording, with complete correspondence to that during recording.

For this reason, conventionally, for example, when taking a four-channel data signal DATA as shown in Figure 1, a channel mode signal CHMODE is added just before the first sample SMP ₁ , and this is read out during playback and used as a data signal. Setting up a multiplexer is being done.

However, with this method, the channel mode signal is added only at one point immediately before a series of data signals, so if the channel mode signal reading fails during playback, the demultiplexer settings will be incorrect and all data will be lost. The problem was that the signal playback became unstable. Furthermore, when changing the number of channels during recording of data signals, a channel mode signal must be added just before the data signal each time, which has the disadvantage that the operation is cumbersome.

This invention was made to eliminate the above-mentioned drawbacks, and by recording channel mode signals at time intervals that have a certain relationship with the sample interval of data signals of a predetermined channel, it is possible to have accurate correspondence with the time of recording. It is an object of the present invention to provide a PCM recording and reproducing device that can obtain stable reproduced data signals.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, reference numeral 1 indicates a PCM recording section, which includes a multiplexer 2, a parallel-to-serial converter 3, a DA converter 4, and a recording device 5. In such a recording section 1, when the channel mode signal CHMODE representing the number of channels is applied to the multiplexer 2 together with the data signal DATA of a predetermined channel, the signal is converted into a digitally coded recording signal sequence, and then the parallel-to-serial converter 3,
The signal is supplied to a recording device 5 via a DA converter 4 and recorded on a recording medium such as a magnetic tape. In this case, the recording signal sequence is such that a channel mode signal is added together with a synchronization signal at time intervals that have a constant relationship with the sample interval of data signals of a predetermined number of channels. In other words, as shown in Figure 3a, in the case of a sample SMP consisting of 8 channels of data signals DATA, a channel mode signal is sent along with a synchronization signal S at each sample SMP time.
If CHMODE is added, in the case of a sample SMP consisting of 4 channels of data signals DATA, the channel mode signal is sent along with the synchronization signal S every 2 samples SMP as shown in Figure 3b.
CHMODE will be added.

On the other hand, 6 indicates a PCM reproducing section, which includes an amplifier 7 to which recorded data is supplied from the recording device 5, a data signal separation circuit 8, a synchronization signal separation circuit 9, a PLL 10, a synchronization control circuit 11, and a serial/parallel converter. 12, a storage device 13 that temporarily stores the data signal DATA, a storage device 14 that temporarily stores the channel signal CHMODE, and a demultiplexer 15
have. In this reproducing section 6, when recorded data is read from the magnetic tape of the recording device 5, it is applied via an amplifier 7 to a data signal separation circuit 8 and a synchronization signal separation circuit 9, respectively. Then, the data signal separation circuit 8 outputs the channel mode signal CHMODE.
The data signal DATA including the synchronization signal S is separated and applied to the serial/parallel converter 12, and the synchronization signal S is separated from the synchronization signal separation circuit 9 and applied to the synchronization control circuit 11 directly and via the PLL 10.

In this state, PLL10 and synchronous control circuit 1
1 outputs the data signal DATA and channel mode signal being output from the series parallel circuit 12.
CHMODE is stored separately in temporary storage devices 13 and 14.

The data signal DATA temporarily stored in the storage device 13 in this way is then sent to the day multiplexer 1 along with the channel mode signal CHMODE.
given to 5. As a result, the data signal DATA is reproduced according to the setting of the channel mode signal CHMODE at this time.

Therefore, with such a configuration, channel mode signals are added at every time interval that has a certain relationship with the sample interval of data signals of a predetermined number of channels, so such channel mode signals are added very frequently. It will be obtained repeatedly. This means that even if the reading of the channel mode signal at a certain point ends in failure, the next channel mode signal can be read out immediately compared to the conventional method in which the channel mode signal is added only at one point immediately before a series of data signals. Since this can be compensated for, the demultiplexer can always be set accurately and a reproduced data signal that accurately corresponds to that at the time of recording can be stably obtained. In addition, since the channel mode signal is repeatedly added at predetermined time intervals, even if the number of channels needs to be changed in the middle of data signal recording, it can be handled by simply switching channels. Compared to inserting a channel mode signal just before the data signal each time the channel mode signal is switched, the operation for this can be extremely simplified.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist.

As described above, according to the present invention, by adding a channel mode signal at each time interval that has a certain relationship with the sample interval consisting of data signals of a predetermined number of channels, a stable signal that accurately corresponds to that at the time of recording is generated. It is possible to provide a PCM recording and reproducing device that can obtain a reproduced data signal.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the format of a conventionally used recording signal series, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIGS. 3a and 3b are diagrams showing the format of a recording signal series used in the same embodiment. It is a figure showing an example. 1...PCM recording unit, 2...multiplexer, 3...
Parallel-serial converter, 4... DA converter, 5... Recording device, 6... PCM playback unit, 7... Amplifier, 8... Data signal separation circuit, 9... Synchronization signal separation circuit, 10...
PLL, 11...Synchronization control circuit, 12...Series parallel circuit, 13, 14...Storage device, 15...Demultiplexer.

Claims (1)

[Claims] 1 Digital coding in which a channel mode signal representing the number of channels is given together with a data signal of a predetermined number of channels, and the channel mode signal is added at every time interval that has a constant relationship with the sample interval consisting of the data signal of a predetermined number of channels. means for generating a recording signal sequence generated by the means; and means for recording the recording signal sequence generated by the means;
The present invention is characterized by comprising means for reading data signals and channel mode signals from this means, and means for reproducing data signals based on the channel mode signals read by this means.
PCM recording and playback device.