JPH06236625A - Recording system for analog audio signal - Google Patents

Abstract

PURPOSE:To accurately restore an original audio signal by recording a unit audio signal in segment unit while scrambling it and simultaneously adding the overlapping part of the audio signal to the unit audio signal. CONSTITUTION:In a recording mode, a specific identification number is inputted from a keyboard or the specific identification number is set beforehand. The presence of set identification number is analized by a CPU 17 as a control section, a scramble pattern is generated based on a random number table generated in the CPU 17 ad this scramble pattern data is set in a register provided in a scramble control circuit 18. Then, a key code is generated from the identification number and the scramble pattern and this is set in another register of the control circuit 18, as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog audio signal recording system suitable for application to a recording / reproducing system of a cassette tape recorder capable of recording a concealed analog audio signal on a recording tape in a predetermined length unit, In particular, the DC component of the reproduced unit audio signal is prevented from becoming discontinuous.

[0002]

2. Description of the Related Art When an analog audio signal is recorded on a recording tape (magnetic tape) using a cassette tape recorder or the like and the audio signal is a highly confidential source, the audio signal is concealed. There are times when you want to record and record.

A conceivable process for concealing an audio signal is to divide a continuous audio signal into segments for each predetermined length as shown in FIG. 17A (segment 1, segment 2, ...), and record it. Occasionally, the segment thus cut out is used as a unit and subjected to a scrambling process as shown in FIG. 9B and recorded according to a predetermined scrambling pattern.

At the time of reproduction, the original audio signal is reproduced by performing the descrambling process of the scramble pattern.

If this scramble processing is performed, even if a person other than a specific operator operates and reproduces this audio signal recorded on the magnetic tape, only a meaningless signal (noise) is reproduced. It is possible to provide a highly confidential recording method.

[0006]

When the audio signal is divided into blocks for each segment and scrambled as described above, the following problems arise.

First, since a cassette tape recorder cannot record an audio signal that rises in a pulsed manner, if the audio signal is simply cut out and recorded, the segments are not correctly connected during descrambling processing during reproduction. Discontinuities will occur. This becomes reproduction noise.

Secondly, since a general cassette tape recorder cannot record a DC component, if an audio signal is cut out in a segment unit and the audio signal in this segment unit is recorded, the audio of the segment is reproduced. It takes some time for the waveform to converge. That is, if an audio signal is recorded in segment units, the DC component of the signal immediately after reproduction (stage before descramble) is different, and the segments become discontinuous, and the original audio signal cannot be reproduced.

Thirdly, when there is fluctuation in tape speed (time axis fluctuation) such as wow or flutter during reproduction, the cutout position as a segment of the audio signal during reproduction becomes uncertain, and a fixed amount of audio signal is generated. When is cut out, the error on the time axis becomes large, and it becomes impossible to reconnect the audio signal.
This also causes noise.

Therefore, the present invention has solved such a conventional problem, and particularly in the present invention, a unit audio signal is recorded while being scrambled in segment units, and at the same time, the cut-out point of the unit audio signal is accurately determined. In order to control the recorded audio signal in synchronization with the recording of the audio signal, the recorded audio signal is designed so that the DC component of the reproduced unit audio signal does not become discontinuous when recording the control signal in a channel different from this audio signal. It was done.

[0011]

In order to solve the above-mentioned problems, according to the present invention, an audio signal is cut out for each unit segment length in a state where an overlap portion is attached to at least the front portion thereof, and the cut overlap is produced. This unit audio signal is continuously recorded on one channel of the recording tape while being compressed on the time axis while being scrambled for each unit audio signal of the unit segment length including the part, and the other unit audio signal is recorded on the other channel. A control signal for cutting out a signal for each unit segment length is recorded.

[0012]

As shown in FIG. 2, for example, the L channel (Lch) of the magnetic tape T is used as a recording area (audio data section) of the analog audio signal, and the R channel (Rch) of the control signal for the analog audio signal is recorded. It is used as an area (control signal section), and both are simultaneously recorded in each channel.

In the audio data section, an audio signal is recorded in block units as shown in FIG.
It is composed of two segments, and each segment is composed of a main segment and an auxiliary segment as shown in FIG. The main segment includes valid data (analog audio signal) and audio data of an overlap portion before and after the valid data. The auxiliary segment is a burst signal for stages (hereinafter referred to as a clear burst signal), and the clear burst signal connects the segments as shown in FIG.

The control signal is mainly for finding the cut-out points (both ends of effective data) of the main segment.
As shown in FIG. 7, there is one header portion for one block, and cutout markers CM indicating data cutout points are respectively associated before and after the identification data ID corresponding to the valid data area in each segment.

At the time of reproduction, effective data is cut out based on this cut-out marker CM.

The unit audio signal is recorded in a state including the audio signals which are overlapped by a predetermined length before and after the unit audio signal. By recording the unit audio signal including the overlap portion, the DC level of the reproduced audio signal at the cut-out point during reproduction becomes the same as the DC level of the original audio signal. Therefore, after playback, D
Even if the C reproduction process is not performed, the DC level between adjacent unit audio signals is continuous.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an example of an analog audio signal recording system according to the present invention applied to a recording / reproducing system of a cassette tape recorder will be described in detail with reference to the drawings.

For convenience of explanation, referring to FIG. 2, in the recording system according to the present invention, as shown in FIG. 2, one channel of the magnetic tape T, for example, an Lch scrambled analog audio signal is recorded, and the other is recorded. A control signal for restoring the scrambled analog audio signal in units of blocks to restore the original audio signal is recorded in the channel Rch of. Therefore, Lch is used as an audio signal recording area (audio data section), and Rch is a control signal recording area (control signal section).
Used as.

As shown in FIG. 3A, an audio signal having a unit length (for example, 600 msec) is recorded as one block on the magnetic tape T in block units. One block is composed of 12 segments as shown in FIG. 9B, and one segment length is 48.06 msec.

One segment is composed of a main segment and an auxiliary segment, and the main segment contains an audio signal. A burst signal (interstage clear burst signal) for connecting the segments is used as the auxiliary segment.

The audio signal inserted in the main segment is added before and after the unit audio signal (hereinafter also referred to as valid data) cut out for each unit segment length as shown in FIG. And an audio signal for overlap of a predetermined length.

The addition of the overlapping audio signal is intended to reduce the influence of the DC component of the unit audio signal and to absorb the speed fluctuation (time axis fluctuation) at the time of reproduction of the tape recorder which is the recording / reproducing section of the signal. This is because

As described above, since a DC component cannot be recorded by a general cassette tape recorder, if an audio signal is cut out in a segment unit and the audio signal in this segment unit is recorded, the audio of the segment is reproduced. It takes some time for the DC component of the waveform to converge.

If an overlapping audio signal is added to the unit audio signal, the audio data at the cut-out point of the effective data, which is the unit audio signal, will have the same DC component as during recording, and the audio waveform will converge. This is because the time to do it will be zero.

The time base fluctuation of the tape recorder is due to wow and flutter of the tape recorder, individual difference of the tape recorder,
The main cause is exhaustion of the battery. This is because if the data is reproduced at a speed different from that at the time of tape recording, the data length of the signal reproduced within a unit time will be different accordingly, and it will be difficult to obtain a continuous reproduced audio signal.

When the overlapping audio signals are added, the time axis fluctuations can be absorbed because the signals are not interrupted even if the time axis fluctuations occur. In this case, fluctuations in the time axis above a certain level are dealt with by controlling the clock frequency on the reproduction side according to the fluctuations in the time axis.

From the point of absorbing the fluctuation of the time axis, the overlapping audio signal may be added only to the front side of the unit audio signal, but in this example, the overlapping audio signal is added before and after the unit audio signal. There is. However, the overlap period is longer on the front side than on the back side. This is to eliminate the fluctuation of the DC component at the data cutout point as described above.

When a unit audio signal including an overlapping audio signal is recorded on the magnetic tape T as described above, even if an audio signal of the same length is recorded as shown in FIGS. The audio signal to be recorded on the magnetic tape T is longer than the original audio signal due to the inclusion.

To avoid this, the signal is compressed on the time axis. The compression of the signal is performed by the write clock for the memory (bank memory) for scramble processing, which will be described later, and the frequency of the clock for the A / D converter provided in association with this memory (both are the same frequency) fw The frequency of the read clock and the frequency of the D / A converter clock (both are the same frequency) fr may be increased. In this example, fw = 24 KHz and fr = 32 KHz are set, and the original audio signal is compressed to 24/32 and recorded. Then, since there is a margin on the time axis due to the compressed amount, the above-mentioned audio signal of the overlap portion and the clear burst signal for connecting the segments are inserted in the time domain.

The scrambled audio signal (voice data) as shown in FIG. 5C is obtained by controlling the read address of the memory in segment units according to the scramble pattern. The length of the unit audio signal when using 24 KHz is 50 msec.
Therefore, if the time axis is compressed using 32 KHz, the length of the unit audio signal after compression is 37.5 mse.
c.

The clear burst signal is used to obtain the stability of the signal waveform at the time of reproduction, and a single sine wave signal (for example, about 6 KHz) is used, and its amplitude is the maximum voice amplitude as shown in FIG. 5C. It is selected to be about 1/2 of the above. Therefore, finally, the signal format in each block is as shown in FIG. 5C, and the signal is recorded on the magnetic tape T in this state.

FIG. 6 shows an example of the segment format, and the figure is shown as digital data after signal compression (the same as the read data from the bank memory) for convenience of explanation.

In the figure, the valid data which is a unit audio signal becomes 1200 bytes, 152 bytes of overlap portion OLF in the preceding stage is added to this, and 28 bytes of overlap portion OLR is added in the succeeding stage. A start clear burst signal is added to the beginning of each block.

The start clear burst signal is longer than the clear burst signal inserted between the stages. This is because the key code is recorded in the control signal part, and the latter is 4.935 m.
It is inserted only for the period of sec, whereas in the former case it is 2
It is inserted only for a period of 3.28 msec.

FIG. 7 shows an example of the format for the control signal section. The control signal portion is composed of a sine wave burst signal of approximately 6 KHz (this is referred to as "1" for convenience) and a sine wave burst signal of approximately 3 KHz (referred to as "0").

As shown in the figure, the header part inserted one per block is a header for identifying the first block (burst signal of "1" with an insertion period of 4.10 msec), and A 16.0 msec key code (consisting of "1" and "0") that was inserted successively, and data KI indicating the end of the key code (the insertion period is 3.12 msec.
And a burst signal of "0").

The key code is a unique code generated from a scramble pattern and a personal identification number input by the operator as described later, and the descrambling process is performed using this key code.

FIG. 8 shows an example of a key code format. In this example, an 8-bit key code is inserted by 5 bytes. Between the key code, start bit and stop bit (marker) of "1" and "0"
Is inserted.

Data as shown in FIG. 7 is also inserted in the control signal portion corresponding to the segment of the audio signal.

In this segment structure, SIF is subheader identification data added before the subheader (burst signal of "1") and is a burst signal of "0". Subheader identification data SI follows the subheader
R (burst signal of "0") is inserted. CM is a cutout marker for indicating the start point of cutout of valid data, and a burst signal of "1" is used.

An identification data ID by a burst signal of "0" is inserted at a position corresponding to valid data. A cutout marker CM (burst signal of "1") indicating a cutout end point of valid data and a marker CE (burst signal of "0") indicating a cutout end point are inserted at the rear end of the identification data ID. .

As described above, the markers CM indicating the data cut-out points are provided before and after the valid data, and the reproduction valid data is accurately cut out by detecting these marker CMs.

The data from the sub-header identification data SIF to the marker CE indicating the end of cutting is data corresponding to one segment, and the relationship between the valid data and the cutting marker CM is as shown in FIG.

According to the above format, the audio signal is recorded on the magnetic tape T in a scrambled state together with the control signal. FIG. 1 shows a concrete example of a recording / reproducing apparatus 10 having a secret talking function. An audio signal to be recorded is supplied to the terminal 11, which is supplied to the low-pass filter 13 via the recording / reproducing switch 12 to be band-limited and then converted into a digital signal in the A / D converter 14.

Clock frequency f when digitizing
As described above, w is 24 KHz in this example. The digital audio signal is stored in the bank memory 15 for each unit audio signal having a unit segment length.

The bank memory 15 is set to 1 as shown in FIG.
The block is divided into three blocks so that 12 segments can be stored, and unit audio signals are stored in corresponding memory blocks A to C on a block-by-block basis. The write clock is 24K, which is the same frequency as the A / D conversion clock.
Hz.

When the unit audio signal is digitized, the data amount becomes 1200 bytes, so that the memory block corresponding to the segment has a capacity of 1200 bytes. In this figure, for example, Seg1-1 is block 1
Means the digital data in the first segment of the. Others are the same.

Data storage is performed in the order of A.fwdarw.B.fwdarw.C.fwdarw.A.fwdarw .. When the data storage in the memory block A is completed, the data read mode is entered in parallel with the data write mode. , B → C → A → B → ・ ・ ・
The data is read in this order. The read clock is selected to be 32 KHz because of time compression of audio data.

When data is read, a part of the data of the segment before and after the segment to be read is read at the same time, and this is used as the audio data for overlap. For example, as shown in FIG. 10, when the segment 3 (Seg1-3) is read, if the data in the areas A and B are read, these audio data A and B will be the data for overlap.

At the time of this data read, the scrambling process is performed in segment units by changing the read order in segment units. In order to perform the scramble processing, it is necessary to give a specific scramble pattern to the memory 15. The explanation will be given below.

In the recording mode, a specific personal identification number is input from the keyboard 16 or a specific personal identification number is set in advance. Whether or not the secret code is set is analyzed by the CPU 17 as a control unit, a scramble pattern is generated based on a random number table generated in the CPU 17, and this scramble pattern data is provided in a register (illustrated in the scramble control circuit 18). No) is set. A key code is generated from the personal identification number and the scramble pattern, which is also set in another register (not shown) of the control circuit 18.

Since the address for the bank memory 15 is controlled based on the scramble pattern, a scrambled output as shown in FIG. 5C, for example, can be obtained. Control circuit 1
From 8 onwards, clock for digital conversion and bank memory 1
A write clock for 5 is supplied.

The scrambled audio data read from the bank memory 15 is converted into an analog signal by the D / A converter 21, and the frequency fr of the clock output from the clock generation circuit 22 at this time is as described above. 32
The compressed audio signal of KHz is band-limited by the low-pass filter 23 and then supplied to the clear burst signal addition circuit 24.

The adder circuit 24 is connected to a generator circuit 25 for control signals including a clear burst signal as shown in FIG. As described above, the control signal generation circuit 25 generates a 3 KHz sine wave signal and a 6 KHz sine wave signal, respectively. However, since the burst signal length differs depending on the insertion position as shown in FIG. 6 or 7, The length of the burst signal is controlled based on the burst command signal from the scramble control circuit 18. this is,
The scramble control circuit 18 includes an RO for timing generation.
Since M19 is associated, this timing signal will produce a burst signal consistent with FIG. 6 or 7.

A command signal for a key code is further sent from the scramble control circuit 18, and a key code as shown in FIG. 8 is generated by the control signal generation circuit 25.

Of the various burst signals generated by the control signal generating circuit 25, the start clear burst signal and the interstage clear burst signal are supplied to the adding circuit 24 and inserted into predetermined positions of the scrambled compressed audio signal. To be done.

After that, it is supplied to the cassette tape recorder 27 in this example for stereo through the recording / reproducing switch 26 and recorded as an audio signal on the Lch thereof. At the same time, the control signal generating circuit 25 sequentially outputs a burst signal of a corresponding length so as to have a format as shown in FIG. 7 while recording the audio signal and synchronizing the burst signal with the burst signal as a control signal to the Rch. Will be recorded.

During reproduction, the switching states of the recording / reproducing switches 12 and 26 are reversed. The compressed audio signal reproduced from the Lch is supplied to the A / D converter 14 via the recording / reproducing switch 12 and the low-pass filter 13, and is once converted into a digital signal. Clock frequency fw used at that time
Is 32 KHz which is the same as when the signal is compressed.

The digitized reproduced audio signal is stored in the bank memory 15 in units of segments. The frequency of the write clock used at this time is 32 KHz
Is.

In this write mode, the tape recorder 2
The amount of data stored in segment units (± m bytes based on 1200 + 152 + 28 = 1380 bytes) increases or decreases as shown in FIG. 11 in accordance with the fluctuation of the time axis due to wow and flutter during playback of No. 7. Therefore, the amount of data that can be stored as one segment is 1 in this example.
Up to 800 bytes are prepared.

In the write and read modes for the bank memory 15 in the reproduction mode, as shown in FIG. 12, the read mode is started when the audio data of 18 segments is written in consideration of the time base fluctuation at the time of reproduction. Controlled by.

Audio data in segment units is read according to a descramble pattern. In order to perform the descrambling process, the following process is executed in the CPU 17 or the like.

At the time of reproducing the scrambled data, the control signal reproduced from the Rch is taken into the CPU 17 through the scramble control circuit 18, and the descramble pattern is generated from the reproduced key code and the personal identification number inputted from the keyboard 16, This is set in the register of the scramble control circuit 18.

When the input personal identification number is incorrect, the correct descramble pattern is not generated, and at this time, the original audio signal cannot be reproduced. At this time, it is possible to display a warning message on the LCD or the like for notifying the operator that the personal identification number has not been correctly entered.

Since the audio data in the segment also includes the audio data of the overlap portion, in order to correctly extract only the unit audio data, the cutout marker CM is detected from the reproduced control signal and Address data is sent to the bank memory 15 in synchronization with the detection point.

By such control of the read timing and control of the address, only the unit voice data excluding the voice data of the overlap portion can be extracted and sent to the D / A converter 21.

During reproduction of the magnetic tape T, tape speed fluctuations such as wow and flutter may occur. In that case, the amount of data written to the bank memory 15 increases or decreases according to this speed fluctuation. Therefore, when the data is read from the bank memory 15, the frequency of the read clock (the reference frequency is 24 KHz) depends on the increase or decrease in the amount of data. Is variably controlled. In other words, when the amount of data to be stored tends to increase, the frequency of the read clock is increased (the clock is increased), and when it is decreasing, the frequency is controlled to be low (the clock is decreased).

Simultaneously with the control of the read clock frequency, the frequency f of the clock given to the D / A converter 21
r is controlled similarly. By performing analog conversion while performing frequency control according to wah and flutter based on the clock frequency fr of 24 KHz, the unit audio signal is returned to the original audio signal linked with the unit audio signal without being affected by speed fluctuations due to wah and flutter. .

Besides the wah and flutter, the speed fluctuation of the magnetic tape T may be a decrease in the tape speed due to the consumption of the battery when the tape recorder 27 is driven by a battery. Even in such a case, the frequency of the read clock is variably controlled as desired as in the case of wah and flutter. In this example, the reference frequency is ± 5% for tape speed fluctuations.
It is configured so that it can be variably controlled to some extent.

As described above, since the time axis expansion processing of the unit audio signal is performed by changing the frequency of the read clock to 24 KHz, if only the unit audio data is correctly cut out and sequentially read in the segment unit, it is descrambled. The audio signal in the closed state is continuously obtained.

The D / A-converted audio signal is band-limited by the low-pass filter 23 and then passes through the clear burst signal adding circuit 24 in a through state (non-processing state), and is further reproduced via the recording / reproducing switch 26. Output terminal 2
8 is output.

The various processing modes as described above are realized by the control program shown below. This control program is stored in the CPU 17.

FIG. 13 is a specific example of the processing flowchart 40 in the scramble recording mode. Recording key (REC
When the key is pressed, it is verified whether or not the personal identification number is preset (step 41). When the specific personal identification number is not set, the scramble processing is not performed and the normal recording mode is set. Return to the original (steps 42 and 43).

When the personal identification number is set, the mode transits to the scramble processing mode, a scramble pattern is first generated under the intervention of the CPU 17, and then a specific key code is generated from the scramble pattern and the personal identification number. The generated key code and scramble pattern are set in the scramble control circuit 18 (steps 44, 45, 46).

When the setting of the scramble pattern and the like is completed, the input audio signal is digitally converted and the data is stored in the bank memory 15 in segment units (step 47). The write clock frequency at that time is 24 KHz.

At the same time as the data write, the data read mode is set in parallel, data is read along with compression of the time axis according to the scramble pattern, and at the same time, a control signal is output and these are recorded on the magnetic tape T (step. 48). This series of scramble recording processing is continued until the stop key is pressed (step 4).
9).

FIG. 14 shows an example of a processing flow chart 50 in the scramble reproduction mode.
When the (y key) is pressed, the personal identification number is checked first, and when the personal identification number is not set, the normal reproduction mode is continued until the stop key is depressed (steps 51, 52, 53). Therefore, the scramble-recorded audio signal cannot be restored unless a personal identification number is input, and in this state, noise is simply reproduced.

When the personal identification number is set, the key code is extracted from the reproduced control signal, and the descramble pattern is generated based on this key code (step 5).
1, 54). Next, the validity of the generated descramble pattern is judged, and if it is judged invalid, the audio mute is applied (steps 55 and 56).

When the descramble pattern is valid, this pattern is set in the scramble control circuit 18, and the A / D conversion process of the reproduced audio signal and the storage process of the audio data are performed at the clock frequency of 32 KHz (step 57). , 58). Then, the audio data is read at the clock frequency of 24 KHz according to the descrambling pattern (descramble processing and time axis expansion processing), and this is continued until the stop key is pressed (steps 59 and 60).

FIG. 15 shows an example of the control program for the bank memory 15, and the figure is an explanation of the reproduction mode.

As is apparent from FIG. 11, the bank memory 15 is divided into three memory blocks.
5, the audio data is sequentially written in the memory block A → B → C → A → ... (Step 7).
1, 72, 73).

FIG. 16 is a specific example of the processing flow chart 80 in the memory read mode in the reproducing mode as well. The frequency of the read clock is set to 24 KHz, and the audio data is sequentially read from the bank memory 15 ( Steps 81, 82).

At this time, the number of write data to the bank memory 15 and the number of read data are compared (step 83). If the tape speed fluctuates, the number of data differs between writing and reading, so the difference is checked. If the difference is within 1 segment (1200 bytes), the tape speed fluctuation is ignored and the same reference clock frequency is used. Data reading continues at 24 KHz (step 84).

When the difference in the number of data is one segment or more, the clock frequency is shifted by ± n% with respect to the reference frequency according to the difference, and the tape speed fluctuation is absorbed (step 85).

In the present invention, the cassette tape recorder is used as the recording / reproducing section, but a deck type tape recorder or another tape recorder can be used. The clock frequency is also an example, and the compression amount of audio data is also arbitrary.

[0086]

As described above, according to the present invention, the unit audio signal is recorded while being scrambled in units of segments, and at the same time, the audio is synchronized with the recording of the audio signal in order to accurately control the cutout point of the unit audio signal. When recording the control signal in a channel different from the signal, an overlap portion of the audio signal having a predetermined length is added to at least the front side of the unit audio signal and the unit audio signal is recorded in that state.

By recording the unit audio signal including the overlap portion in this way, the DC level of the reproduced audio signal at the reproduction cut-out point becomes the same as the DC level of the original audio signal. As a result, the DC level between adjacent unit audio signals becomes continuous even if the DC reproduction process is not performed again after the reproduction, so that the original audio signal can be accurately restored.

Therefore, the present invention is extremely suitable when applied to a battery-driven cassette tape recorder or the like.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of a cassette tape recorder to which the present invention is applied.

FIG. 2 is a diagram showing a format of a recording tape.

FIG. 3 is a diagram showing a relationship between an audio data section and a control signal section.

FIG. 4 is a diagram illustrating segment segmentation from an original audio signal.

FIG. 5 is a waveform diagram of a scrambled audio signal.

FIG. 6 is a diagram showing a detailed format of an audio data section.

FIG. 7 is a diagram showing a detailed format of a control signal section.

FIG. 8 is a diagram for explaining a key code format.

FIG. 9 is a diagram showing a mutual relationship between an audio data section and a control signal section.

FIG. 10 is an explanatory diagram showing a memory usage example in a recording mode.

FIG. 11 is an explanatory diagram showing a memory usage example in a reproduction mode.

FIG. 12 is a diagram showing an example of memory control in a reproduction mode.

FIG. 13 is a diagram showing an example of a processing flowchart in a scramble recording mode.

FIG. 14 is a diagram showing an example of a processing flowchart in a scramble reproduction mode.

FIG. 15 is a diagram illustrating an example of a processing flowchart of a memory write mode during reproduction.

FIG. 16 is a diagram showing an example of a processing flowchart of a memory read mode during reproduction.

FIG. 17 is a diagram for explaining the present invention.

[Explanation of symbols]

 14 A / D converter 15 Bank memory 17 CPU 18 Scramble control circuit 19 Timing ROM 21 D / A converter 24 Clear burst signal addition circuit 25 Control signal generation circuit

Claims (1)

[Claims] 1. An audio signal is cut out for each unit segment length in a state where at least a front part thereof is provided with an overlap part, and the time axis is scrambled for each unit audio signal of a unit segment length including the cut out overlap part. This unit audio signal is continuously recorded in one channel of the recording tape in a compressed state, and the control signal for cutting out the above unit audio signal for each unit segment length is recorded in the other channel. A recording method for analog audio signals that is characterized by