JP2575101B2 - Audio signal recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal recording apparatus, and more particularly, to detection of an audio signal digitally recorded on a recording medium,
The present invention relates to an audio signal recording device having an identification function.

<Description of Prior Art> Conventionally, various identification functions have been added to an audio signal recording apparatus. In particular, in a recording apparatus capable of recording for a long time and recording an audio signal of high sound quality, a cueing function is required.

Conventionally, as a method of performing cueing in an audio tape recorder, a tape is run at a speed several to several tens of times the speed at the time of recording, and a silent portion of an audio signal reproduced along with this is detected. I was

On the other hand, in recent years, various techniques for recording an audio signal using a rotating head have been disclosed with the improvement in audio quality of the audio signal. For example, FM modulation recording using a rotating head is known as audio hyphenation in a video tape recorder, and digital modulation recording using a rotating head is known as a dedicated audio machine.

In response to this, an audio recorder that compresses the audio signal on the time axis and records the digital signal by digital modulation has been devised.

The following briefly describes an example of an audio tape recorder that compresses an audio signal on the time axis using a rotating head and performs digital modulation recording.

FIG. 1 is a diagram showing an example of a tape running system of this type of conventional audio tape recorder. In Figure 1
Is a magnetic tape, and 2 is a rotary cylinder that holds the rotary heads 3 and 4. As a result, the heads 3 and 4 trace the tape 1 diagonally and record audio signals. Each time the heads 3 and 4 are rotated by 36 °, an audio signal whose time axis is compressed in each of the six areas formed in the longitudinal direction of the tape 1 is recorded, so that a total of six channels of audio signals can be recorded. A special tape recorder can be obtained.

Hereinafter, this tape recorder will be briefly described. FIG. 1 is a diagram showing a tape running system of the above-described tape recorder, and FIG. 2 is a diagram showing a recording locus on a tape by the tape recorder.

In FIG. 2, CH1 to CH6 are heads 3 or 4, respectively, in which A to B, B to C, C to D, D to E, E in FIG.
To F, and from F to G are areas where audio signals are recorded. An audio signal can be separately recorded in each area, and so-called azimuth overwriting is performed respectively. However, the tracks of the areas CH1 to CH6 do not need to be on the same straight line. A pilot signal for tracking control is recorded in each area, and it is assumed that a pilot signal is recorded in each area in a predetermined rotation (f ₁ → f ₂ → f ₃ → f ₄ ). There is no correlation between them.

The areas indicated by CH1 to CH3 are recorded / reproduced when the tape 1 is running at a predetermined speed in the direction indicated by the arrow 7 in FIG. 1, and the areas indicated by CH4 to CH6 are also indicated by the direction indicated by the arrow 9 in FIG. It is recorded and reproduced when running. Accordingly, as shown in FIG. 2, the inclination of each track in the area indicated by CH1 to CH3 and the inclination of CH4
The inclination of each track in the region indicated by .about.CH6 is slightly different.
However, at this time, the difference between the relative speeds caused by the running of the tape 1 is extremely small compared to the difference caused by the rotation of the heads 3 and 4, so that no problem occurs.

FIG. 3 is a time chart for recording and reproduction of the tape recorder as described above. In the figure, (a) is a phase detection pulse (hereinafter referred to as PG) generated in synchronization with the rotation of the cylinder 2, and is a 30 Hz pulse that repeats "high level (H)" and "low level (L)" every 1/60 second. It is a square wave. (B) is a PG having a polarity opposite to that of the PG (a). Here, it is assumed that PG (a) is H while the head 3 rotates from B to G in FIG. 1, and PG (b) is H while the head 4 also rotates from B to G in FIG.

FIG. 3 (c) is a data reading pulse obtained from PG (a) for sampling an audio signal in a period corresponding to one field (1/60 second) of a video signal every other field. is there. FIG. 3 (d) shows a signal processing period H for adding a redundant code for error correction or changing the arrangement of the sampled audio data for one field using a RAM or the like. FIG. 3 (e) shows the period of data recording by H, and shows the timing at which the recording data obtained by the above-described signal processing is recorded on the tape 1.

For example, if the signal flow is temporally followed using FIG. 3,
Data sampled during the period from t1 to t3 (head 3 is moving to BG) is subjected to signal processing from t3 to t5 (head 3 is G to A), and t5 to t6 (head 3 is A to B). ). That is, it is recorded in the area of CH1 in FIG. 2 by the head 3. On the other hand, data sampled during the period when PG (b) is H is subjected to signal processing at the same timing, and is recorded in the area of CH1 by the head 4.

FIG. 3 (f) shows a PG obtained by shifting the PG (a) by a predetermined phase (here, 36 ° for one area).

Hereinafter, a case where an audio signal is recorded by using PG (f) and a PG (not shown) having characteristics opposite to the above will be described. Third
The data sampled in FIGS. T2 to t4 is subjected to signal processing according to the signal shown in FIG. 3 (g) during t4 to t6, and recorded according to the signal shown in FIG. 3 (h) during the period t6 to t7. That is, the data is recorded in the area indicated by CH2 in FIG. 2 by the head 3 while the head 3 traces B to C. Sync to t4
The data sampled during the period from to t7 is recorded by the head 4 in the area indicated by CH2.

Next, an operation of reproducing a signal recorded in the area indicated by CH2 will be described.

The reading of data from the tape 1 by the head 3 is performed from t6 to t7 (the same applies to t1 to t2) according to the signal shown in FIG. 3 (h), and is read from t7 to t8 (t2) according to the signal shown in FIG. 3 (i). The signal processing reverse to that at the time of recording is performed at t3). That is, error correction and the like are performed in this period, and t8 is further performed according to the signal shown in FIG.
A playback audio signal is output from to t9 (t3 to t6). Of course, the reproducing operation using the head 4 is performed with a phase difference of 180 ° from the above-mentioned operation, whereby a continuous reproduced audio signal is obtained.

Further, for other areas CH3 to CH6, PG (a)
Needless to say, the recording / reproducing operation may be performed based on this phase, and this does not depend on the running direction of the tape.

In this way, it became possible to use a VTR as a dedicated audio device capable of recording for a long time with multiple channels.

However, this type of audio tape recorder can quickly find out what part of the tape is recorded, for example, even if recording 90 minutes in each area can record for as long as 9 hours. It is difficult to do.

That is, when a tape as a recording medium is run at high speed, the head cannot accurately trace on the recording track. Therefore, a reproduced audio signal cannot be obtained from the PCM audio signal, and it is impossible to detect a silent portion.
In addition, the silent part also corresponds to the information of the silence.
Since the PCM audio signal is recorded, it is impossible to detect the presence or absence of the recording signal.

<Object of the Invention> The present invention has been made in view of the above-described problems, and even when an audio signal is recorded as digital data, searching for an audio signal that is digitally recorded on a recording medium, An object of the present invention is to provide an audio signal recording device capable of easily performing identification.

<Description by Example> Hereinafter, the present invention will be described using examples.

FIG. 4 is a diagram showing a schematic configuration of a tape recorder as one embodiment of the present invention. 4, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

The PG obtained from the rotation detector 11 of the rotary cylinder 2 is supplied to a cylinder motor control circuit 16 to rotate the cylinder 2 at a predetermined rotation speed and a predetermined rotation phase. Reference numerals 12 and 13 denote rotation detectors of the flywheels 17 and 18 of the capstans 14 and 15, respectively. These outputs (FG) are selectively supplied to a capstan motor control circuit 20 via a switch 19. The output of the circuit 20 is a capstan 14 or 15 at the time of recording.
Are supplied to the respective capstan motors via the switches 21 so that the rotation of the motors becomes a predetermined speed. The switches 19 and 21 are connected to the F side in the figure when the tape runs in the direction shown by the arrow 7 (forward direction), and to the R side in the figure when running in the direction shown by the arrow 9 (reverse direction).

By manually operating the operation unit 24, an operation mode such as recording and reproduction and an area to be recorded and reproduced are designated. In addition, it is specified whether recording is to be performed exclusively for audio or video signals are to be recorded in the recording pattern shown in FIG.

These data are supplied to the system controller 25, which controls the capstan motor control circuit 20, the switches 19 and 21, the area designating circuit 26, the gate circuit 27 and the like. Then, the area specifying circuit 26 supplies the area specifying data to the gate pulse generating circuit 23 to obtain a desired gate pulse. Note that the area specified when a video signal is also recorded is naturally CH1.

As the control gate pulse for the gate circuit 28, the above-described window pulse is selectively supplied to each of the head 3 and the head 4 based on the area designation data.

At the time of recording, the analog audio signal input from the terminal 29 is supplied to the PCM audio signal processing circuit 30 and is sampled at the above-described timing relating to the window pulse, converted into digital data, and then subjected to the above-described signal processing. The recording audio data thus obtained is output from the pilot signal generating circuit 32 for each field, f ₁ → f ₂ → f ₃ →
the tracking pilot signals and other pilot signals which will be described later generated in Roteshiyon of f ₄ to be added by the adder 33. The output of the adder 33 is appropriately gated by the gate circuit 28 as described above, and is written to a desired area by the heads 3 and 4.

At the time of reproduction, the reproduced signals of the heads 3 and 4 are also extracted by the gate circuit 28 by the window pulse, and this reproduced signal is supplied to the low-pass filter (LP) through the A-side terminal of the switch 34.
F) It is supplied to 35 and to the PCM audio circuit 30. In the PCM audio circuit 30, signal processing such as error correction, time axis expansion, digital-analog conversion, etc. is performed in the reverse of recording, and the reproduced analog audio signal is supplied to a terminal 36.
Output more.

The LPF 35 separates the aforementioned tracking pilot signal and supplies it to the ATF circuit 37. The ATF circuit 37 is a circuit for obtaining a tracking error signal by a well-known four-frequency method.
It is well known that the reproduced pilot signal for tracking and the pilot signal generated by the pilot signal generating circuit 32 in the same rotation as the recording are used. However, when used as an audio-only device, a tracking error signal is obtained for each area, and this is sampled and held. The tracking error signal thus obtained is supplied to the capstan motor control circuit 20, and the running of the tape 1 during reproduction is controlled via the capstans 14 and 15 to perform tracking control.

Next, recording and reproduction of a video signal will be described. When an instruction to record and reproduce a video signal is issued from the system controller 25, the area designating circuit 26 forcibly designates the CH1 area, and operates the gate circuit 27 according to the PG. The video signal input from the terminal 38 is converted into a signal form suitable for recording by the video signal processing circuit 39 and then supplied to the adder 40. Then, the adder 40 adds the pilot signal obtained from the pilot signal generation circuit 32 to the pilot signal, and records the added signal via the gate circuit 27 in the areas CH2 to CH6 by the heads 3 and 4. The recording operation of the PCM audio signal at this time is C
This is exactly the same as the above-described recording operation for H1.

At the time of reproduction, the video signal picked up from the heads 3 and 4 is converted into a continuous signal via the gate circuit 27.
This continuous signal is supplied to the video signal processing circuit 39, converted into the original signal form, and output from the terminal 41. The continuous signal obtained from the gate circuit 27 is supplied to the LPF 35 via the V terminal of the switch 34.

In LPF35, the pilot signal component is separated continuously and ATF
The signal is supplied to the circuit 37. At this time, the tracking error signal obtained from the ATF circuit 37 does not need to be sampled and held, and is supplied to the capstan motor control circuit 20 as it is. At this time, the PCM audio signal is also reproduced from the area of CH1, and an analog audio reproduction signal is obtained from the terminal 36, but tracking control using the output signal of the gate circuit 28 is not performed.

Next, the cueing function of the tape recorder of this embodiment will be described. FIG. 5 is a diagram showing an example of a specific configuration of the cueing control circuit 51 shown in FIG. 4, and FIG. 6 is a timing chart showing waveforms of respective parts in FIG.

In FIG. 5, reference numeral 61 denotes a terminal to which an L channel recording audio signal is supplied, and 62 denotes a terminal to which an R channel recording audio signal is supplied. 63 is an adder, 6
This is for temporarily returning the stereo audio signal input from 1,62 to a monaural audio signal.

Now, when the recording audio signal is interrupted, a so-called silence state occurs, and the output signal level of the adder 63 decreases. The detection circuit 64 performs envelope detection and the like of the output signal of the adder 63, and when the detection level falls below a certain threshold level, the output of the inverter 65 (shown in FIG. 6B) changes to a high level.

When the output of the inverter 65 is at a high level, a silent period is set. The mono-multi (MM) 66 is triggered by the rise of the output of the inverter 65, and turns to a low level after a predetermined period (T1). At this time, since the output of the inverter 68 changes to the high level, the output of the monomulti 67 (shown in FIG. 6D) and the output of the AND gate 69 (shown in FIG. 6E) also change to the high level. On the other hand, the mono-multi 67 is triggered by the fall of the output of the mono-multi 66, and changes to a low level after a predetermined period (T2). OR gate 70 is the output of AND gate 69 and MM 67
Of the inverter 65 is turned to low level, and the output of MM67 is turned to low level when the output of MM67 is turned to low level.

FIG. 6 shows a case where the period of the silent state is longer than T1 + T2. In this case, when the period of the output of the OR gate 70 is at the high level (T3), and when the period of the silent state is T, T ₃ = represented by T-T _1. However, when T ₁ <T <T ₂ −T ₁ , T ₃ = T _{2 as} is clear from FIG. On the other hand the T ₃ = 0 when T of <T _1.

The output of the OR gate 70 is supplied to the PCM audio signal processing circuit through the terminal 71, only during a period of T ₃ the beginning detection data to be described later, outputs from the PCM audio signal processing circuit 30 together with the data corresponding to the audio signal The configuration is as follows.

To consider this, first case of the beginning, mainly but must detect between tracks, the period of T ₁ so as not would provide an discriminated between tracks silence short is set, A silence period shorter than this period is not determined to be a music interval. It seems preferable to set the T ₁ for example approximately 2 seconds before and after. Of course, this T ₁ are those that can be appropriately determined depending on the application.

For then T ₂ are those determined according to the tape ratio of the traveling speed of the time and the beginning search time of recording. That is,
It is sufficient to set a period long enough to detect the pilot signal for cueing when the tape is run at high speed. For example, specifically, the field pressure at which the tape runs at 30 times speed may be set to a period of 30/60 seconds or more. The detection is repeated several times (x
Times) If you want to do it, it will be more than x / 2 seconds.

Hereinafter, an example of a data format applicable to the present embodiment will be described. FIG. 7 shows a data format recorded in one track of each area in FIG. 2, that is, 1/60.
FIG. 8 is a diagram illustrating an example of a format of data including PCM audio data corresponding to a second audio signal.

In the data matrix shown in FIG. 7, a column indicated by sync is a data column for synchronization, a column indicated by sdress is an address data column, columns indicated by P and Q are redundant data columns for error correction, CRCC, respectively.
The columns indicated by are the well-known CRCC check code data columns, D1, D2
Are data strings each including a plurality of columns and each including audio signal information. On the other hand, b (0) to b (3x−1) indicate each row of the data matrix, and each row corresponds to 1
One data block is sequentially recorded from the left side to the right side in the figure. For example, after the sync column data of b (0), the address column data of b (0) are sequentially recorded, and then the P column data of b (0) are sequentially recorded. Also b
After the last column data of (l), sync column data of b (l + 1) is recorded, and when the last column data of b (3x-1) is recorded, data recording for one track is completed.

Here, in the first column among the columns included in D1, b (0), b
(1), 6 of b (x), b (x + 1), b (2x), b (2x + 1)
One of the data (ID0 to ID5) can be recorded so as not to include the information of the audio signal. That is, the cueing data is recorded using this portion.

In this embodiment the manner indicating that the the format of a cue data is recorded in 8 bit data indicated by ID0, also recorded on tracks corresponding to predetermined bits of 8-bit data indicated by ID1 to T ₃ described above It is set to "1" for those that are performed, and to "0" otherwise. At this time ID0 and ID1
Is handled as one pair, it is desirable that the data be recorded at a close timing, and this is also taken into account in the data matrix.

Next, the recording and reproduction of the cue data will be described.
FIG. 8 is a diagram showing a specific example of the PCM audio signal processing circuit in FIG. 8, 101 is a terminal 29
Is a terminal to which an input analog audio signal is supplied, and 102 is a terminal to which an output from the cueing control circuit 51 shown in FIG. 5 is supplied. When a high-level signal is supplied to the terminal 102, the data generating circuit 104 generates data that sets the predetermined bit of the data corresponding to ID1 to "1". When a low-level signal is supplied to the terminal 102, data for setting the predetermined bit of ID1 to "0" is generated.

On the other hand, the analog audio signal input to the terminal 101 is supplied to an analog-to-digital converter (A / D) 103.
In the A / D 103, the analog audio signal is sampled at a predetermined frequency, quantized, and supplied to the data selector 105 at a predetermined timing. The data selector 105 outputs the data generation circuit 1 at the timing corresponding to ID1 once in one field period.
The output of 04 is supplied to a RAM (random access memory) 107, and the output of the A / D 103 is supplied to the RAM 107 at other timings. The RAM 107 stores the parity word (P, Q) obtained from the error correction circuit (ECC) 106, the address data obtained from the address controller 108, such as the CRCC, and the data obtained from the data selector 105 in the seventh place. They are arranged so as to correspond to the data matrix shown in the figure. Data that has been time-axis compressed in the order described above is supplied from the RAM 107 to the modulation circuit 109,
The modulation circuit 109 performs digital modulation such as BPM (bi-phase, modulation, modulation) or the like, and outputs the result via a terminal 111. The digitally modulated audio signal output from the terminal 111 is supplied to the adding circuit 33 as described above.

Next, the operation at the time of reproduction will be described. The digital modulation signal from the terminal 112 via the gate circuit 28 is demodulated by the digital demodulator 113 and supplied to the RAM 115. R in RAM115
Signal processing completely opposite to that of AM107 is performed. That is, the array is changed based on the address data obtained from the address controller 114 and further on the synchronization data, and the ECC 116 corrects the error. Along with this, the obtained data of the D1 column and the D2 column are output from the RAM 115 and supplied to the D / A (digital-analog converter) 117 and the data reading circuit 118.

The D / A 117 restores the original analog audio signal and outputs it from the terminal 36 in FIG. On the other hand, the data reading circuit 118 picks up the data of ID1 described above, and supplies a pulse signal to the cue detection circuit 52 via the terminal 120 every 1/60 second when the predetermined bit of ID1 is "1".
It is assumed that the operations of the respective parts of the signal processing circuit shown in FIG. 8 are all synchronized by a timing signal generated by the timing controller 110.

Next, the cueing using the signal obtained from the data reading circuit 118 in FIG. 8 will be described. FIG. 9 is a diagram showing an example of a specific circuit configuration of the cue detection circuit 52 in FIG. In FIG. 9, the output of the data reading circuit 118 is supplied to a terminal 122.

Even when the tape is run at high speed, the heads 3 and 4 cross the heading specified area once every 1/60 second, so when entering the part corresponding to the above T3, the data of ID1 is 1/6.
You can get it only once in 0 seconds. At this time, the heads 3 and 4 are set to be sufficiently larger than the recording track pitch to perform azimuth overwriting. That is, it is assumed that data can be picked up even if tracking is not performed. Since the heads 3 and 4 cross the recording track diagonally, the playback signal is not a continuous wave, but contains 3x synchronization data, and ID1 can be extracted using this synchronization data. It is assumed that

In FIG. 9, 121 is supplied with the PG described above.
In the one-shot multi 123, a pulse is formed every 1/60 second in synchronization with the PG and supplied to the AND gates 125 and 127. on the other hand,
When a pulse is supplied to the terminal 122, the retriggerable monomulti 124 is triggered, and when a pulse is input every 1/60 second, the output of the retriggerable monomulti 124 keeps a high level during that time. Now, if the set length of T ₃ at least head can trace 4 times (4n / 60 seconds), the T ₃
, Four pulses are obtained from the AND gate 125. The AND gate 12 is other than a period corresponding to T ₃
Pulse is obtained from 7.

If four consecutive pulses are obtained from the AND gate 125, the counter 128 supplies a high-level Q output to the counter 131. The output pulse of AND gate 127 is OR gate 129
Resets the counter 128 via. Also counter 128
The counter 128 is reset for a while (e.g., several seconds) after the Q output of the SYNC goes high. This prevents erroneous recognition of silent parts and counting errors due to long silent parts.

DA is data for designating the number of the beginning of the music. If the data matches the output data of the counter 131, the comparison circuit 132 outputs a high-level output and triggers the mono-multi 133. The output of the mono multi 133 is supplied to the capstan control circuit 20 shown in FIG. 4 via a terminal 134, and operates the capstan control circuit so that the tape stops.

According to the tape recorder of the above-described embodiment, the search and identification of the recorded audio signal of the audio tape recorder for performing the digital recording can be performed without any trouble of the user.

In the above-described embodiment, the cueing data is separately recorded as specific data. However, a part of the data corresponding to the audio signal may be used. The width of the head is if unchanged so as Toratsukupitsuchi is Yari set longer relative to T ₃ to the tape speed during Date search, also constitutes so as to determine a silent section if detectable only once in several times It is also possible.

<Explanation of Effects> As described above, according to the present invention, even when an audio signal is recorded as digital data, it is possible to easily search and identify an audio signal digitally recorded on a recording medium. It became possible to.

[Brief description of the drawings]

1 is a diagram showing a tape running system of a conventional tape recorder, FIG. 2 is a diagram showing a recording format of the recorder shown in FIG. 1, and FIG. 3 is a timing showing recording / reproducing timing of the recorder shown in FIG. FIG. 4 is a diagram showing a schematic configuration of a tape recorder as one embodiment of the present invention, FIG. 5 is a diagram showing a specific example of a cueing control circuit in FIG. 4, and FIG. 5 is a timing chart showing the operation of the circuit of FIG. 5, FIG. 7 is a diagram showing a data matrix for explaining a recording data format by the recorder of this embodiment, and FIG. 8 is a diagram of the PCM audio signal processing circuit of FIG. FIG. 9 is a diagram showing a specific example, and FIG. 9 is a diagram showing a specific example of a cue detection circuit in FIG. Reference numerals 3 and 4 denote heads, 29 an audio signal input terminal, 30 a PCM audio signal processing circuit, 51 a cueing control circuit, 64 a detection circuit, and 104 a cueing data generation circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsutomu Fukatsu 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. Tamagawa Works (72) Inventor Masahiro Takei 770 Shimonoge, Takatsu-ku Kawasaki Canon Inc. Tamagawa Works (72 ) Inventor Koji Takahashi 770 Shimonoge, Takatsu-ku, Kawasaki City Inside Canon Co., Ltd. (72) Inventor Tomohiko Sasaya 770 Shimonoge Shimoge, Takatsu-ku Kawasaki City Inside Canon Co., Ltd. Tamagawa Business Office (56) References JP 60-1654 (JP, A)

Claims (1)

(57) [Claims] An audio signal is input, a silence portion of the audio signal having a level lower than a predetermined level is detected from the input audio signal, and a detection signal indicating a period of the silence portion of the detected audio signal is detected. Detection means for generating a detection signal, and a detection signal generated by the detection means is input. When a period of a silent portion of the audio signal indicated by the input detection signal is shorter than a first predetermined period, an index signal is output. Does not occur, and when the period of the silent portion of the audio signal is longer than the first predetermined period and shorter than the second predetermined period following the first predetermined period, the starting point of the silent portion of the audio signal The first predetermined period has passed since the first
The index signal is generated for a predetermined period from the timing of
If the period of the silent portion of the audio signal is longer than the second predetermined period following the first predetermined period, the first period
An index signal generating unit that generates the index signal during a period from the timing of to the end of the silent section of the audio signal; a modulation unit that modulates the input audio signal into a digital audio signal and outputs the digital audio signal; Recording means for recording, on a recording medium, the index signal generated by the preceding index signal generating means together with the digital audio signal output from the modulating means.