JPS6124062A - Pcm recorder - Google Patents

Abstract

PURPOSE:To attain re-recording of sub-data by utilizing a recording track of an error correction signal after a PCM signal and the error correction signal are recorded on all tracks of a magnetic tape. CONSTITUTION:The re-recording of sub-data is constituted that a switch 88 is connected to the S2 position, the sub-data is inputted from an auxiliary input terminal 27 and a signal encoded into a prescribed signal format is recorded on a track (20) by a sub-data encoder 32. An error correction Q code is recorded on the track (20) at recording of the voice signal is and since the code is missing by re-recording of the sub-data, the correcting capability is reduced. In re-recording the sub-data, when the tape running speed is set to a larger value in advance at the recording of the sound signal, the reduction in the correction capability due to the re-recording of the sub-data is avoided.

Description

[Detailed description of the invention] (a) Industrial application field The present invention provides P O'M (pulse hood modulation) for audio signals.
The present invention relates to a PCM recording device that converts signals into signals and records them on a magnetic recording medium such as a magnetic tape, and particularly relates to additional functions of the device.

(b) Conventional technology When converting an audio signal into a PCM signal, the signal transmission speed is almost determined by the sampling frequency and the number of quantization bits of the audio signal). For example, if the sampling frequency and the number of quantization bits are each 50 KHz. , 16 pits, the transmission speed of the PCM signal becomes 800 Kbit/sec, which is more than an order of magnitude faster than the transmission speed of the original audio signal.

Furthermore, when stereo audio signals are multiplexed, the PC
The transmission speed of the M signal is approximately 1600 Kbit. However, it is not possible to record PCM signals at such transmission speeds using a conventional analog audio magnetic recording and reproducing apparatus that uses magnetic tape.

For example, in a fixed head type digital magnetic recording and reproducing device that uses the same magnetic tape, in order to achieve this,
A method is used in which a PCM signal with a high transmission speed is distributed to a plurality of tracks on a magnetic tape, and the transmission speed of each recording track is made slower than the transmission speed of the PCM signal. In the case of the aforementioned PCM signal with a transmission rate of 1600 Kbit/s 1 For example, if the number of tracks to be distributed is set to 18, the transmission rate of each track is 1600/18-:89 Kbit.
t/second, which is a transmission speed within the range that can be recorded by conventional analog audio magnetic recording and reproducing devices.

Generally, when recording and reproducing PCM signals, a signal is required to correct errors, and FIG. 1 shows a pattern on a magnetic tape when counting for this signal.

Track numbers ■~@ contain signals obtained by converting audio signals into PCM signals, and track numbers 0... An error correction signal is recorded in [phase]. Note that T is the width of the magnetic tape, and recording is performed at a width A relative to the width T of the tape.

On the other hand, in so-called digital magnetic recording and reproducing devices that record and reproduce audio signals by converting them into PCM signals,
It is possible to multiplex and record sub-data other than the audio PCM signal, such as text information and graphics 1, onto the audio PCM signal.

Conventionally, this has been achieved according to the signal format shown in FIG. That is, in FIG. 2, (21+, (22, (
), (241d One block usually consists of 100 bits to 200 tens of pits. Synchronization signal L2D
is added for detecting the block, the error detection signal @ is added for detecting data error in the block, and aa and Q3 are the PCM signals of the sub data and voice, respectively. PC of sub data and audio using the block as a unit
The M signal is distributed to each track and recorded.

I/4 Problems to be Solved by the Invention However, when recording using this method, sub data and audio PCM
The signals must be recorded simultaneously; re-recording only one of them is not possible. On the other hand, regarding sub-data, if it is difficult to prepare it at the same time as audio information,
For example, in the case of real-time recording such as broadcast air checks and on-site recordings, a function to re-record sub-data later is desired. In order to solve this problem, a method has been proposed in which a track dedicated to recording sub-data is provided in addition to the tracks shown in FIG.
7410) However, 1 For example, in Figure 1, the tape width T is the compact cassette standard! If the width is as narrow as 81fla, it is difficult to increase the number of tracks for signal tracking purposes.

2) Means for Solving the Problems The present invention provides a method for solving the above-mentioned problems in all tracks (tracks ① to ＠) of a magnetic tape, including the audio PCM signal shown in FIG.
After recording the matte signal and the error correction signal, when re-recording the sub-data, the recording track of the error-correction signal is used to re-record the sub-data on the track.

(E) Operation With the above configuration, it is possible to re-record sub-data without adding a track dedicated to sub-data recording.

(f) Example The embodiment of the present invention shown in FIG. 6 will be described.

FIG. 3 is an example in which the number of tracks is 20.

Stereo audio input terminal (c), (audio signals input from each of 261 are sent to the A/D converter (support) J)
After being converted to a PCM signal, the error correction code generation circuit
(to)], a P code and a Q code are generated, respectively.

Next, error detection codes are generated for every several words to several words by the 0ROO generation circuit [1) 1 for each series of audio PCM signals, P codes, and Q codes, and then a synchronization signal is added and frame distribution is performed. The circuit (2) adds a synchronizing signal to the beginning of the front cover film detection code generation block, and distributes the block to each track as one frame.

The signal format after distribution is as shown in Figure 4.
In the case of 20 tracks, track ■ to track [phase] are the audio PCM signals indicated by W, tracks O,
A P code and a Q code for error correction are distributed to @, respectively.The P code and Q code are generated based on the formula (2) and (2), respectively. Here, n is a positive integer.

p 18n+1)1w1B n 10'ΦW1an+!
(E)−・−・−@w 1) 1n+18−・・■Q18
n-1-1-T”W18n+1ΦT”Wlan+l■・
・・・・・・・・・■'rwlan+16 ・・・・・・
・・・・・・・・・・・・・・・・・・・・・・■ Also, ■ represents (modulus2) for each bit of the word, T , T , ... , T represents the generation matrix for adjacent codes.

Next, the signals distributed to each track are subjected to modulation, such as MFM, by a modulation/recording circuit, and then recorded onto a magnetic tape by a recording head. At this time, it is assumed that the switch (2) is connected to the 81 side.

Next, when reproducing a signal, the signal on the magnetic tape is detected by the reproducing head η, then the signal is amplified and demodulated between the reproducing and demodulating circuits, and the synchronizing signal detecting and frame synthesizing circuit ( 79).

The circuit (79) detects the synchronization signal added to the beginning of the frame, and then synthesizes the signals for each track into one series of signals. The synthesized signal is subjected to signal error detection by the error detection circuit (2), and then signal errors are corrected by the P error correction circuit (f31) and the Q error correction circuit (31), and then D/A conversion is performed. It is converted into the original audio signal upstream from the converter and outputted from the audio output terminals - and H. Here, it is assumed that the switch is connected to the Fi81 side.

The above is the normal recording and playback of audio signals.

Next, re-recording and reproduction of sub-data according to the present invention will be explained.

In the present invention, re-recording of sub-data is achieved by connecting the switch (3) shown in FIG. The signal encoded in the signal format is configured to be output to the track@. During reproduction, the sub-data signal is reproduced from the track [phase],
A signal is taken out from the track [phase] output between the reproducing/demodulating circuits, and the sub data decoded into the original signal according to the sub data decoder diagram is output from the sub data output terminal (b).

By the way, a Q code for error correction is recorded on the track [phase] when the audio signal is recorded, and this code is lost when the sub data is re-recorded.

[KQ erroneous cal correction is not possible] during reproduction, and the correction ability is degraded. However, this problem can be solved as follows. That is, in magnetic recording and reproducing capacity using a magnetic tape, as shown in FIG. Since the error rate shows a tendency to decrease as shown in FIG.

This can be addressed by changing the tape running speed as described above.

Therefore, in the present invention, when re-recording sub-data, if the tape running speed is set to a large value in advance when recording the audio signal, the correction ability by re-recording the sub-data can be improved. It is possible to avoid a decrease in

Although the above-described embodiment has been described using the double error correction method for adjacent codes as an example, the correction method is not limited to that method. Further, the present invention is also applicable to an error correction method that uses a so-called interleaving method in which data is recorded in a distributed manner in the running direction of the tape and in the width direction of the tape.

(G) Effect As described above, according to the present invention, after recording an audio signal, sub-data such as information related to the signal can be re-recorded without adding tracks to a limited tape width. This makes it possible to improve the functionality of a fixed head type PCM magnetic recording/reproducing device using magnetic tape without affecting the tracking accuracy of signals.

[Brief explanation of drawings]

Fig. 1 shows the recording pattern on the magnetic tape when the number of tracks is 20, Fig. 2 shows the signal format of the conventional sub-data recording method, and Fig. 3 shows the PCM magnetic tape explaining the sub-data recording method according to the present invention. A block diagram of the recording/reproducing device, FIG. 4 is a signal format for explaining the present invention, and FIG. 5 is a graph of error rate for explaining the present invention. , @・− Auxiliary input terminal, ゛ (to)
...Sub data encoder, (to) - magnetic tape,
■・・・Switch・

Claims (2)

[Claims] (1) An audio input terminal and an auxiliary input terminal; after converting the audio signal input from the audio input terminal into a PCM signal, generating a redundant code for error correction from the signal; It has a magnetic recording circuit that records PCM signals on a plurality of tracks on a magnetic tape, and a circuit that encodes sub-data inputted from the auxiliary input terminal. A PCM recording device characterized in that it is configured to re-record an encoded signal of sub-data input from the auxiliary input terminal on a track in which a redundant code is recorded. (2) A patent claim characterized in that when re-recording the encoded signal of the sub-data inputted from the auxiliary input terminal, the running speed of the magnetic tape is set in advance to be higher than the normal speed when recording the PCM signal. The PCM recording device according to item 1.