JPS62273641A - Recording and reproducing device for pcm sound signal - Google Patents

Abstract

PURPOSE:To attain fast and automatic program search by recording an index signal to a scheduled part of a sound track in a frequency different from the frequency of PCM sound data. CONSTITUTION:A sound signal inputted from an input terminal 1 is fed to PCM processor 3 via an A/D converter 2. The processor 3 applies pulse code modulation to the signal based on a timing signal PCM 30 fed from a PCM timing signal generating circuit 16 to supply the PCM signal AP to a switch 4. An index signal Ind fed from a frequency division circuit 20 is inputted to the other terminal of the switch 4 and the switch 4 switches the signal Ind and and the signal AP to supply the result to a recording amplifier. The amplifier 5 switches sequentially both the signals and records the result to the selected track. The signal Ind in a scheduled frequency is detected from the reproducing signal at the high speed search reproduction and the high speed search reproduction is stopped in response to the detection so as to detect the head of each music accurately and quickly.

Description

[Detailed Description of the Invention] V. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a PCM audio signal recording and reproducing device, and in particular, a PCM audio signal recording and reproducing device using a helical scan method to record and reproduce a large number of time-axis compressed PCM audio signals. The present invention relates to a PCM audio signal recording and reproducing apparatus that can record signals and perform suitable high-speed cueing during reproduction.

[Conventional technology]

In recent helical scan type VTRs, there is a tendency to improve the quality of audio signals. One specific method is to convert the audio signal into a digital signal, compress the time axis for each field period, and then convert the audio signal (PCM audio signal) onto an extension of the video signal recording track. A method is known in which recording is performed on a track formed during a period (overlap period) in which at least two magnetic heads scan a tape.

VT that supports time axis compression PCM recording of such audio signals
In R, for example, as described in Japanese Unexamined Patent Publication No. 58-222402, a method has been proposed in which a time-base compressed PCM audio signal is recorded also on a track where a video signal is originally recorded. Hereinafter, this method will be referred to as the PCM multi-track recording method.

This proposal divides the video signal recording track into five equal parts,
By recording time-base compressed PCM audio signals for each, overlapping periods are included.

A total of six PCM audio tracks are formed.

Therefore, when this VTR is used as an audio-only device, the recording time is six times longer than when used for normal video, and high-quality PCM audio signals can be recorded and played over a long period of time.

Specifically, if we consider the case where a tape with a recording time of 2 hours is used, the recording time will be six times as long as 12 hours, making it possible to record more than 100 songs of ordinary music.

[Problem that the invention seeks to solve]

However, in the above PCM multi-track recording method, since long-time recording and playback is possible, during playback, "playback",
There has been a problem in that searching for a song to be played, so-called cueing, by repeated operations such as "rewind" and "fast forward" is extremely troublesome and takes a long time.

An object of the present invention is to solve the above-mentioned problems of the PCM multi-track recording system, and to provide a PCM audio signal recording system that enables high-speed and automatic cueing even when playing back a tape on which many songs are recorded. The purpose is to provide a playback device.

[Means for solving problems]

In order to achieve the above object, the present invention provides a time axis compression PC.
In the scheduled part of the audio track where M audio data will be recorded,
An index signal as information such as the beginning part, the end part, or the part between songs of the confession is recorded at a frequency different from the frequency of the PCM audio data. On the other hand, during playback, the tape is run at high speed, and the above-mentioned index signal is extracted from the playback signal (by the playback index gate signal), and the high-speed tape run is stopped in response to the detection of the playback index signal. It is characterized by the fact that it is

[Effect]

Since the index signal as information such as the beginning part, the end part, or the inter-song part of the recorded confession is recorded at a frequency different from the frequency of the PCM audio data, it may be affected by the PCM audio data. Without,
It becomes possible to detect the index signal, and as a result, it becomes possible to locate the beginning of a song without error.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

Figure 1 shows a P
FIG. 2 is a block diagram showing an embodiment of a recording system of a PCM audio signal recording and reproducing apparatus compatible with the CM multi-track system.

In Figure 1, 1 is an audio signal input terminal, 2 is an analog-to-digital conversion circuit (AD converter), and 3 is a PC.
M processor, 4 is a switch, 5 is a recording amplifier, 6 is a cylinder, 7a and 7b are heads, 8 is a magnetic tape, 9 is a capstan, 10 is a capstan motor, 11 is a pinch roller, 12 is a cylinder rotation phase detection head (tack head), 13 is a head rotation phase detection signal generation circuit, 1
4 is a servo system reference signal generation circuit, 15 is a servo circuit,
16 is a PCM timing signal generation circuit, 17 is a PCM system master clock generation circuit, 18 is a gate signal generation circuit, 19 is an AND circuit, 20 is a frequency dividing circuit, 21 is a timer, 22 is a switch, 23 is a resistor, 24 is an input terminal for a track selection signal.

The operation of FIG. 1 will be explained below according to the signal flow.

In FIG. 1, an audio signal input through the input terminal 1 is supplied to an AD converter 2. In FIG. The AD converter 2 samples the input audio signal using a sampling pulse SCK having a frequency of, for example, 2f (f is the horizontal synchronizing signal frequency of the video signal) supplied from the master clock generation circuit 17, and then converts the input audio signal into a digital signal. and supplies it to the PCM processor 3.

The PCM processor 3 converts the input digital audio signal into, for example, one field period (1/1/1 of the cylinder rotation period).
After interleaving, adding an error detection/correction code, and compressing the time axis to approximately 1/7 based on the timing signal PCM30 supplied from the PCM timing signal generation circuit 16, the pulse The signal is code-modulated and supplied to the L-side input terminal of switch 4. Furthermore, PC
The above digital signal processing in the M processor 3 is as follows:
This is performed using the master clock MCK supplied from the master clock generation circuit 17.

In addition, in this embodiment, as a pulse code modulation method,
It uses pi-phase mark modulation.

This pi-phase mark modulation is a method in which the state is inverted at the boundary of each bit, and if the data is "1", the state is also inverted at the center of the bit period.
For the data string shown in (1), Vi becomes a modulated signal as shown in (2) of the same figure. In addition, in this embodiment, time axis compression P
The transmission bit rate of the CM audio signal is 568fa=5.7
9MBPS (5,79 x 1 o' bits/sec), therefore, the master clock MCK is (3) in Figure 2.
As shown in , the highest frequency 2 of the time-domain compressed PCM signal
736f'B = 11.58MHz.

An index signal Ind for high-speed cueing supplied from the frequency dividing circuit 20 is input to the H-side input terminal, which is the other input terminal of the switch 4. therefore,
This switch 4 connects the index signal Ind and PC
The M signal AP is switched and supplied to the recording amplifier 5. The switching control of the switch 4 will be explained in detail later.

The recording amplifier 5 converts the PCM signal AP and index signal Ind input from the switch 4 into a timing signal P.
The condylar level is switched according to CM30 and the gate signal PCMGT, and the two heads 7a and 7b are supplied at a predetermined timing, and the six tracks (N11 to N1) shown in FIG.
a6). This recording timing will be explained in detail using FIG. 3.

In Figure 3, %(1) is the head rotation phase detection signal 5W.
30, and this signal 5W30 is generated by the head rotation phase detection signal generation circuit based on the tack pulse TP generated from the tack head 12 in a predetermined phase relationship with the rotation phase of the heads 7a and 7b for each rotation of the cylinder 6. This is a signal generated by the (sw3o generation circuit) 13. This signal 5W5
0 and the heads 7a and 7b, the head 7a is
The signal 5W30 falls when 36 degrees have passed from the input side of the tape 8, which is 216 degrees of winding, and the signal 5W30 rises when the head 7b has passed 36 degrees from the input side of the tape 8. Therefore, during the period when the signal SW 30 is at a low level, the head 7a scans the sixth track from Nα2 shown in FIG. From number 2 of Figure (A), Na
6 tracks are scanned.

(2) in FIG. 3 is the timing signal PCM30,
PCM timing signal generation circuit (PCM30 generation circuit)
Generated at 16. This signal PCM30 is a signal that determines the generation timing of the time-base compressed PCM audio signal in the PCM processor 5, and is also a signal that switches the recording signal RS supplied to the heads 7a and 7b in the recording amplifier 5.

Subscript numbers 1, 2, 5 in Fig. 3 (2). ...6 is
N11, N12,..., number 6 shown in Figure 4 (A)
This corresponds to selecting each track. This timing signal PCM30 is a head phase detection signal 5W30.
This is a signal whose phase is delayed by 36° (N-1') (N is the track number 1 to 6 shown in FIG.
M30-2゜...Track selection signal T supplied from the PCM30-6 through the input terminal 24 shown in FIG.
One is selected by S.

(3) in FIG. 3 is a gate signal PCMGT that determines the switching timing in the recording amplifier 5 (recording timing by the heads 7a and 7b).
It is recorded only while CMGT is at a high level. The gate signal PCMGT is generated by counting the master clock MCK generated by the master clock generation circuit 17 based on the edge of the timing signal PCM30.
It is generated by the gate generation circuit 18. Subscript numbers 1, 2, 3 in Figure 3 (3). . . . 6 is the subscript number 1, 2, 3, . . . of the timing signal PCM30 shown in FIG. 3(2).・
...6 is supported.

This gate signal PCMGT is a timing signal PCM5.
Stand up at 36° before the 0 edge9. Its width is equal to the recording period of the PCI signal and index signal.

(4) in FIG. 3 shows the recording signal RS supplied to the heads 7a and 7b. The signal shown by the solid line is head 7.
This is the recording signal supplied to the head 7b, and the signal indicated by the broken line is the recording signal supplied to the head 7b. helmet, subscript number 1
．． 2, 3. ...6 is the above two signals PCM
Similarly to No. 30 and PCMGT, they correspond to N11, m2, . . . No. 6 of the track shown in FIG. 4(A).

Here, the servo for cylinder rotation and tape running will be explained. First, in the cylinder servo, the head phase detection signal 5W30 generated based on the tack pulse TP generated by the rotation of the cylinder is synchronized with the reference signal Ref30 generated by the servo system reference signal generation circuit 14. controlled as follows.

The reference signal Ref30 is generated by, for example, an oscillator using a crystal oscillator, and is a signal with a stable frequency. In this embodiment, the frequency of the reference signal Ref30 is selected to be the frame frequency (one half of the vertical synchronization signal frequency in the video signal), and therefore, the frequency is approximately 30 Hz.

Further, tape running servo is performed by synchronizing the rotational phase of the capstan motor 10 with the reference signal Ref30. Therefore, the capstan 9 in FIG. 1 rotates the tape 8 with the tape 8 sandwiched between it and the pinch roller 11, thereby causing the tape 8 to run at a constant speed.

Next, the format of the signal recorded on each track will be explained. In this embodiment, one track is divided into five areas a, b, . . . e, as shown in FIG. 4(A). The contents of these five areas are as shown in Figure 4 (B), where a is a reserve area (clock run-in area) for reproducing a clock synchronized with data during playback, and b is a PCM area. audio data area,
C is the separation area between the PCM audio data area and the index signal area, d is the index signal area, and e is the separation area between the upper and lower tracks (separation area).
guard area). The width of each area and the recording data signal are as shown in FIG. 4(B). Note that the width of the area is expressed by the tape winding angle, and the value in parentheses is expressed by the head scanning time. Here, the single iH is the horizontal synchronization signal period in the video signal, for example, IH=1/f
El #6! It is L6μsec.

Here, a method for recording the index signal will be explained. The index signal is a signal for determining whether the track being scanned by the head is at the beginning of a song, during a song, or between songs during high-speed cue playback. In this embodiment, the index signal is set to 1,4475 MHz, which is one-eighth of the frequency of the master clock MCK, when representing the beginning of the song, and 1,4475 MHz, which is one-eighth of the frequency of the master clock MCK, when representing the beginning of the song. 5, which is 1/2,
79MHz is assigned. Same, this 5.79MHz
corresponds to all 11'' of the pi-phase mark modulated PCM signal.

The 1.4475 MHz index signal representing the beginning of the song is not recorded on just one track, but is recorded on 300 tracks from the beginning of the song, as shown in Figure 5, in consideration of track skipping during high-speed search. I try to record it over a period of time. Recording control of this index signal is performed by the switch 4 shown in FIG.

In FIG. 1, the switch 22 is momentarily turned on at the beginning of each side, and a pulse IP as shown in (2)K of FIG. 5 is supplied to the timer 21. The timer 21 uses the above pulse IP
A signal TGT that becomes a constant signal is generated for a period of time during which 300 tracks are recorded from the time when the signal TG is input.
T is supplied to the AND circuit 19. The index gate signal RIGT supplied from the gate signal generation circuit 18 is input to the AND circuit 19. Therefore, the AND circuit 19 performs an AND operation between the start signal 'I'GT of the song and the index gate signal RIGT. The output signal SC is supplied to the switch 4. Note that the index gate signal R
IGT is generated in the gate signal generation circuit 18 by counting the master clock MCK with reference to the timing signal PCM30. FIG. 6 shows the generation timing of the index gate signal RIG'I'.

In FIG. 6, (1) is a timing signal PCM3G.

(2) is the gate signal PCMGT indicating the recording timing.
.

(3) is the index gate signal RIGT, and (4) is the recording signal R3. As is clear from FIG. 6, the output signal SC of the AND circuit 19 is at the beginning of the song (30Cl
The index gate signal RIGT is at a high level only during the output period of the index gate signal RIGT, and is at a low level during other periods.

The switch 4 is closed to the H input terminal side while the output signal SC of the AND circuit 19 is at a high level, and the switch 4 is closed to the H input terminal side while the output signal SC of the AND circuit 19 is at a high level.
The index signal 1nd is supplied to the recording amplifier 5.

On the other hand, the switch 4 is closed to the L input terminal side while the output signal SC is at a low level, and the PCM processor 3 outputs the
The CM signal AP is supplied to the recording amplifier 5. In addition, the above P
The CM signal AP is all of the pi-phase mark modulated PCM signal except for the generation period of the time axis compressed paM audio signal.
1 #, that is, a single frequency signal of 5.79 MHz. Therefore, the signal recorded in the index signal area d is a signal of 1,4475 MHz, which is one-eighth of the master clock MCK, during the 300 track period at the beginning of the song, and is a signal of 1,4475 MHz, which is one-eighth of the master clock MCK. It is a signal of 5,79 +4 Hz, which is one half of MCK.

Here, the reason why 1.4475 MHz is selected as the frequency of the index signal representing the beginning of the song will be explained. In general, in the helical scan type V'I'R, due to variations in the mechanism part between each set, etc.
An error occurs in the recording position of the signal. Now, as an error between each set of recording positions, for example, as shown in Fig. 7, the maximum error is ±1.5) ((
Considering the case where an error (with respect to the longitudinal direction of the track) occurs, the relative error between the set at the time of recording and the set at the time of reproduction is at most ±5H. Therefore, the reproduction index gate signal PIGT for index signal extraction during reproduction, which will be described later, must be made wider than 3H (corresponding to the tape winding angle of 2.06°) which is the period of the actual index signal area.

By the way, in this way, the reproduction index gate signal PI
If GT is widened, a pi-phase mark modulated audio signal may be included in the output period of this gate signal PIGT. For this reason, the index signal 1nd must have a frequency that can be separated from the pi-phase mark modulation signal component shown in (1) of FIG. Furthermore, in order to prevent an increase in circuit scale, it is desirable that the frequency be a frequency obtained by dividing the master clock MCK. Furthermore, in Figure 8 (
Considering the low-frequency cut-off characteristics in the magnetic recording/reproducing system shown in 2), the index signal frequency needs to be several hundred KHz or more in order to ensure the reproduction amplitude of the index signal. From the above, it can be seen that the appropriate frequency of the index signal representing the beginning of each plane is a signal from 1,445 MHz to 362 KHz, which is obtained by dividing the 1158 MHz master clock by 8 to 32. Therefore, in this embodiment, frequency division by 8, which has the smallest frequency dividing circuit scale, is adopted.

FIG. 9 is a block diagram showing another example of the generation and control circuit for the index signal Ind.

The difference in FIG. 9 from FIG. 1 is that the index signal indicating the beginning of the song is generated using the PCM signal AP output from the PCM processor 3. As mentioned above, the PCM signal AP is time-base compressed P
Except for the period when the CM audio data is generated (the period when the head is scanning the PCM audio data area b in FIG. 4(A)), all of the bi7 engineering mark modulation signals are "1",
In other words, it is a single frequency signal of 5.79 MHz. Therefore, in FIG. 9, when recording an index signal indicating the beginning of a song, the frequency of the PCM signal AP supplied from the PCM processor 3 is divided by four in the frequency dividing circuit 33, and the frequency is 1.44.
75 MHz is obtained, switched by switch 4, supplied to recording amplifier 5, and recorded in index signal area d4C. The output signal SC of the AND circuit 19 for controlling the switching of the switch 4 is the same as that shown in FIG.

FIG. 10 is a block diagram showing another example of the index signal generation and control circuit.

FIG. 10 shows the PCM output from the PCM processor 3.
This shows an example of the generation of an index signal when the signal AP is only time-axis compressed PCM audio data.

In FIG. 10, the 11.58 MHz master clock MCK supplied from the master clock generation circuit 17
are converted into index signals of 5.79 MHz and 1.4475 MHz by the frequency divider circuit 34 and the frequency divider 35, respectively, and are supplied to the L-side input terminal and the H-side input terminal of the switch 36. The switch 36 outputs a signal T representing the beginning of the song (30 (1 rack period) explained in FIG.
When the signal TGT is at a high level, it is closed to the H side, and when the signal TGT is at a low level, it is closed to the L side. The index signal output from the switch 36 is supplied to the H-side input terminal of the switch 37. PCM audio data supplied from the PCM processor 3 is input to the L-side input terminal, which is the other input terminal of the switch 37 .

The switch 37 is controlled by the index gate signal RIGT for recording explained in FIG. , is closed to the L side input terminal. As a result, the PCM audio data and index signal output from this switch 37 are transferred to the PCM audio data and index signal on the tape via the recording amplifier 5.
It will be recorded in the audio data area b and the index signal area d, respectively.

Next, the reproduction system will be explained. FIG. 11 is a block diagram showing an embodiment of a playback system of a PCM audio signal recording and playback apparatus compatible with the PCM multi-track system that enables high-speed cue playback by applying the present invention.

In FIG. 11, 25 is an output terminal for the reproduced audio signal;
Reference numeral 6 indicates an input terminal for a song number designation signal at the time of cueing, 27 a preamplifier, 28 a gate circuit, 29 an index signal detection circuit, and 30 a decoding circuit.

31 is a digital-to-analog conversion circuit (DA converter), and 32 is a system controller.

Note that blocks similar to those described in FIG. 1 are indicated by the same reference numerals as in FIG. 1. The operation of FIG. 11 will be explained below according to the signal flow.

In FIG. 11, the tape 8 is
The reproduced signal PS reproduced from above is supplied to the preamplifier 27. After sufficiently amplifying the reproduction signal ps, the preamplifier 27 switches the amplified reproduction signal using the timing signal PCM30 supplied from the PCM1 generation circuit 16, and outputs the PCM block, processor 3, and gate circuit. Supply to 28. The switching of the reproduction signal PC is recorded in a selected track among the six tracks shown in FIG. 4(A) during a period of 36 degrees before both edges of the timing signal PG:Ml. This is done so that the PCM signal is reproduced.

The reproduced signal pr supplied from the preamplifier 27 to the PCM processor 3 is subjected here to the reverse processing to that during recording. That is, pi-phase Mars demodulation, time axis expansion, error detection and correction, dinterleaving, etc. are performed. still,
The PCM signal processing is performed using the 11.58 MH2 master clock MCK supplied from the master clock generation circuit 17, as in the case of recording. The digital audio signal output from the PCM processor 3 is supplied to the DA converter 31, where it is sampled and held using the tempering pulse SCK with a frequency of 2 fH supplied from the master clock generation circuit 17. ,
After being converted into the original analog audio signal, it is outputted via the output terminal 25.

On the other hand, the reproduced signal PF supplied to the gate circuit 28 is extracted by the reproduced index gate signal PIGT supplied from the gate signal generation circuit 18, and the signal only during the period when the gate signal PIGT is at a high level is extracted. The extracted signal is supplied to the index signal detection circuit 29. The reproduction index gate signal PIGT is a timing signal P
This is a signal generated by the gate signal generation circuit 18 by counting the master clock MCK with CM30 as a reference.

Here, the generation timing of the reproduction index gate signal PIGT will be explained. This gate signal PIG
As explained in the recording system section above, the width of 'F allows the index signal recorded in the index signal area to be Index signal detection circuit 2
It must be able to supply to 9. Therefore, in this embodiment, the reproduction index gate signal PIGT is used.

The width is 9H (tape wrapping corresponds to 6.17° of the corner). In this way, the required width of the gate signal PIGT is set to 9H.
This will be explained in detail using FIG. 12.

(1) to (9) in the twelfth section indicate the relative reproduction timing of the index signal. Note that the symbols a, b, c, ...e in the same figure refer to (A) and (B) in FIG.
It shows each area shown in .

First, a case where the reproduction set has an error of +1.5H, which is one of the cases where the recording position error between sets is maximum, will be described. (1) in Figure 12 is +15
The timing of the index signal of the reproduction set shifted by H is shown. On the other hand, the timing of the index signal actually reproduced is as shown in (2), (3), and (4) in FIG. 12, depending on the error in the recording position of the record set. In the same figure, (2) is a case where the record set is shifted by +1.5H, (3) is a case where the record set is a standard product, that is, there is no shift, and (4) is a case where the record set is -1,
This is a case where there is a deviation of 5H.

By the way, when reproducing in sectors shifted by +1.5H, the reproduction index gate signal PIGT.

The width must include all reproduction periods of each index signal shown in (2), (3), and (4)K in FIG.

On the other hand, another case in which the recording position error between sets is maximum will be described, which is a case where the reproduction set has an error of -1.5H. (5) in Figure 12 is -1
, 5H shows the timing of the index signal of the playback set shifted by 5H. On the other hand, the timing of the index signal that is actually reproduced depends on the error in the recording position of the record set, as shown in (6), (7), and (8) in Figure 12.
It's like K. In (6) of the same figure, the record set is -1,5H
(7) is a case where the recording set is a standard product,
In other words, there is no shift, and (8) is a case where the record set is +
This is a case where there is a deviation of 1.5H. By the way, this -1,
In the case of reproduction with sets shifted by 5H, the width of the reproduction index gate signal PIGT is r6) in FIG. 12,
It is necessary to include all reproduction periods of each index signal shown in (7) and (8).

From the above, the reproduction index gate signal PIGT
With respect to the playback timing shown in Figure 12 (9), the width of 9H must span from 1.5H before the end of the PCI audio data area, as shown in Figure 4. becomes clear.

The reproduced index signal PInd extracted by the gate circuit 28 by the index gate signal PIGT having the above width is supplied to the index signal detection circuit 29. The index signal detection circuit 29 detects 1.447 which represents the beginning of the song out of the reproduction index signal Plnd.
Only the 5MH2 component is detected, and a signal DI that is at a high level only during the period when this 1.4475MHz index signal is reproduced is supplied to the decoding circuit 30. The decoding circuit 30 determines that the detection signal DI is a signal with a pulse width of about 3H at the longest, and that the index signal is a signal with a pulse width of about 3H.
Since the tracks are recorded over the same track, the plurality of signals DI detected from the beginning of the same song are judged as one song, and a one-pulse song count signal is generated each time the beginning of the confession is played. PM is supplied to the system controller 32.

The system controller 32 receives the number of songs count signal P.
It counts N and compares it with the cue number designation signal SN supplied via the input terminal 26. Then, when the number of songs to be reproduced matches the designated number of songs for cueing, a stop signal for stopping tape running is output to the servo circuit 15. As a result, in this embodiment, tape running is stopped at the beginning of a desired song, and the beginning of one song is found.

In this embodiment, the above-mentioned cueing operation is performed at several tens of times the tape running speed during normal playback.

As is clear from the above description, according to this embodiment, each P
An index signal for cueing can be recorded in the postamble part of PCM audio data in the CM audio track,
High-speed cueing becomes possible.

Furthermore, in this embodiment, since a frequency different from the frequency of the PCM audio data is selected as the index signal representing the beginning of the song, there is a discrepancy in the recording position between the set at the time of recording and the set at the time of playback. Even if the index signal represents the beginning of the song, it is possible to accurately detect the index signal representing the beginning of the song. Moreover, in this embodiment, the frequency of the index signal is a frequency obtained by dividing the master clock, so there is no need to provide a new oscillator for the index signal, and an increase in circuit scale can be prevented.

In this embodiment, the index signal of the predetermined frequency is recorded at the beginning of the confession to find the beginning of the song, but the present invention is not limited to this case.
For example, the index signal can be recorded at the end of a song, between songs, or at any part of a confession (for example: - By recording the index signal at the joint between each movement in classical music, the index signal can be recorded during playback. It will be clear that cueing of any point is possible.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, PCM
The index signal can be recorded separately from the audio data, so the index signal can be detected by high-speed search during playback, and the number of songs and the beginning of a confession can be detected accurately and quickly. Because it can be done,
It is possible to quickly locate the beginning of a desired song, and the operability during playback can be significantly improved.

In addition, in the present invention, the reproduction gate width of the index signal is
Since the width of the recording gate is made wider than the recording gate width, even if the recording position is different between the recording set and the reproduction set, it is possible to accurately detect the index signal, and it is possible to achieve compatibility of the apparatus during reproduction.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the recording system of the PCM audio signal recording and reproducing apparatus of the present invention, FIG. 2 is a waveform diagram of the biphase mark modulation signal and master clock, and FIG. 3 is the timing of the main signals. 4 is a diagram of the tape and track format, FIG. 5 is a recording timing chart of index signals, FIG. 6 is a timing chart of index gate signals, FIG. 7 is a diagram showing variations in recording positions, and FIG. 8 is a frequency characteristic diagram, FIGS. 9 and 10 are block diagrams showing other examples of index signal generation and control circuits, respectively, and FIG. 11 is a PCM of the present invention.
FIG. 12, a block diagram showing an embodiment of a reproduction system of an audio signal recording and reproduction apparatus, is a diagram showing variations in reproduction timing of index signals. 3... PCM processor, 4... Switch 13...
- Head rotation phase detection signal generation circuit 16... PCM timing signal generation circuit 17... Master clock generation circuit 18... Gate signal generation circuit, 19... AND circuit 20... Branch circuit, 21... - Timer 22... switch, 28... gate circuit 29... index signal detection circuit 30... decoding circuit 32... system controller 53, 34.35... frequency dividing circuit, 56.57. ··switch.

Claims (1)

[Claims] 1. A recording track formed by helical scanning is divided into a plurality of tracks in the longitudinal direction of the track, and at least a time-axis compressed pulse code modulated audio signal is recorded in each of the divided tracks. In the PCM audio signal recording and reproducing device, each of the divided tracks is further divided into at least two regions in the longitudinal direction of the track,
means for recording a time-base compressed pulse code modulated audio signal in the divided first area and an index signal related to the recorded audio signal in a second area; means for detecting an index signal of a scheduled frequency from a reproduced signal during high-speed search playback by the high-speed search means; PCM audio signal recording, comprising means for stopping the high-speed search playback in response to detection of a signal, wherein the frequency of the index signal of the scheduled frequency is made different from the frequency of the pulse code modulated audio signal. playback device. 2. The predetermined frequency index signal is generated by frequency-dividing a master clock for pulse code modulated audio signal processing.
CM audio signal recording and reproducing device. 3. The index signal of the predetermined frequency is recorded in a group of tracks at the beginning of the pulse code modulated audio signal.
PCM audio signal recording and reproducing device as described in 2. 4. The index signal detection means for the scheduled frequency includes gate means for allowing the reproduced signal to pass through for a scheduled period, and an index for detecting the index signal for the scheduled frequency from among the passing reproduced signals and outputting a detection signal corresponding to the detected index signal. It comprises a signal detection circuit and a decoding circuit that outputs a one-pulse signal in response to the detection signal, and is characterized in that the scheduled period is set longer than the actual reproduction period of the index signal of the scheduled frequency. A PCM audio signal recording and reproducing device according to claim 1, 2, or 3.