JPH10162501A - Voice information transmission method, voice information transmission device, and voice recording device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To superimpose additional information without deteriorating the sound quality of an analog audio signal. SOLUTION: An instantaneous interruption section having a length that is hard to be heard as a click sound is provided in a section excluding a section having a sudden rise and a large amplitude of an audio signal and a section in which the component of the section is a narrow band. Is used to superimpose the additional information on the analog audio information. As a method of superimposition, there is a method of inserting additional information into an instantaneous interruption section and superimposing it, a method of using the length of an instantaneous interruption section as additional information, and a method of using the position of an instantaneous interruption section as additional information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for superimposing additional information such as a copy protection control signal and copyright information for tracking illegal duplication on audio information.

[0002]

2. Description of the Related Art Recently, digital audio devices such as a compact disk (CD) player and a so-called mini disk (MD) system have become widespread, and it has become possible to easily reproduce and view high-quality sound. Is coming.

However, on the other hand, there is a problem that music software provided in abundance may be copied indefinitely, and various countermeasures for preventing copying have been taken.

[0004] In particular, in the case of digital audio as described above, since the audio signal is not degraded by duplication, this duplication prevention measure is important. Therefore, in the case of digital audio as described above, a copy protection control signal including a copy protection code or a copy generation limit code, copyright data, and the like are added to the digital audio signal as digital data and recorded. By recording on a medium, duplication is prohibited, and tracking of a recording medium copied using copyright data is performed.

However, when a digital audio signal is converted into an analog audio signal, the analog audio signal does not include the information added as the digital data. Becomes impossible.

[0006]

Therefore, it is desirable that the above-described additional information can be superimposed on an analog audio signal. However, it has been very difficult to superimpose the additional information on the analog audio signal without deteriorating the S / N of the audio signal.

[0007] For example, it is conceivable to superimpose additional data on an analog audio signal by using spread spectrum, which has recently attracted attention. However, in order to superimpose the additional information as a spread spectrum signal without deteriorating the S / N of the voice signal, the level of the spread spectrum signal cannot be increased, and the audio band is narrow and the spread coefficient is small. Because it is not large, it is difficult to detect and extract the spread-spectrum additional information by despreading,
In particular, a long detection time or a large-scale apparatus is required.

Further, it is preferable that the superimposed additional information can be rewritten in some cases. For example, if the additional information is copy prevention control information and generation restriction information, the additional information must be rewritten so that the first recording is permitted and the second recording is prohibited.

However, when the additional information is superimposed on the analog audio signal by spectrum spreading, it is very difficult to erase and rewrite the previous additional information.

The present invention solves the above problems, and is not limited to a digital audio signal, but can be applied to an analog audio signal.
It is an object of the present invention to provide a method and apparatus capable of superimposing additional information while minimizing deterioration of voice quality.

[0011]

In order to solve the above-mentioned problems, in the voice information transmitting method according to the present invention, a portion of a voice signal having a sharp rising edge and a large amplitude and a section in which the component of the section is a narrow band are excluded. In the section, an instantaneous interruption section having a time length that is hard to be heard as a click sound is provided, and additional information is superimposed on analog audio information using the instantaneous interruption section.

The portion of the audio signal that has a sharp rise and has a large amplitude is called an attack.
The effect on sound quality is large. For this reason, superimposing the additional information on the attack portion easily causes deterioration of the S / N of the audio signal.

An experiment on perception of a click sound with respect to a band noise burst (magazine: JAS Journal)
1, '85 February edition), the wider the bandwidth,
It was confirmed that the click sound became hard to hear.

According to the magazine, "the time range contributing to the masking of the click sound can be considered as a first-order approximation of a so-called psychological time window of the auditory system, and only the conclusions of the experiment will be described. The above assumption is correct, and the time range contributing to masking is approximately 10 ms (milliseconds, the same applies hereinafter). " In the instantaneous interruption section having a time length of about 1 ms to about 1 ms, the click sound is almost masked, so that the listener cannot hear it.

In the audio information transmission method according to the present invention having the above-described configuration, the instantaneous interruption section used for superimposing the additional information is a part other than the attack part, and
The voice in the section is wideband. The instantaneous interruption section is set as, for example, a section having a length that is hard to be heard by a click sound having a length of 10 ms or less.

Therefore, according to the present invention, even when the additional information is superimposed by providing an instantaneous interruption section, as described above, the click sound due to the superimposed burst-like additional information can be hardly heard. Therefore, additional information can be superimposed on an analog audio signal without deterioration of sound quality.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a voice information transmitting method according to the present invention.

In the present invention, an instantaneous interruption section is provided in the analog audio signal, and additional information such as a copy protection control signal or copyright information is superimposed on the instantaneous interruption section. FIG.
Shows an example of a circuit configuration for forming the instantaneous interruption section in an analog audio signal.

As described above, the length D of the instantaneous interruption section is 1
The time may be 0 ms or less, but in the case of an actual music signal, it is preferably 100 μs to 1 ms.

In the case of this example, the two conditions that the instantaneous interruption section is immediately before the attack of the audio signal and that the audio signal component in the section of the length D of the instantaneous interruption section is distributed over a wide band are as follows. At the same time, the section is determined to be satisfied.

For this reason, in the example of FIG. 1, the input analog audio signal Si is supplied to an attack detecting section 11 and a spectrum analyzing section 12.

The attack detecting section 11 detects a portion of the input analog audio signal that has a sudden rise and a large amplitude as an attack, and supplies the time when the attack is detected to the microcomputer 13 as an output. This attack detection can be detected, for example, as a case where the audio signal rises at a steep slope that is equal to or greater than a predetermined slope and the peak value exceeds a predetermined value. Note that the detection output may be generated at any time when the level exceeds the predetermined level or when the peak value is detected.

In this case, the microcomputer 13
The output of the attack detection unit 11 is fetched, for example, at a fixed timing interval τ (τ ≦ D, usually sufficiently shorter than the length D), and the attack detection unit 11 detects an attack portion in the input analog audio signal. Monitor whether or not.

The spectrum analysis unit 12 calculates the interval Pa from the present time (the timing of the attack detection timing) to the set short time interval D by a margin time α minutes.
Of the input analog audio signal. In this case, the margin time α is at least equal to or longer than the maximum value of the delay time from the start of the attack part to the detection of the attack part by the attack detection unit 11.

Then, the spectrum analyzer 12 detects the frequency distribution of the audio signal in the section Pa from the result of the spectrum analysis of the input analog audio signal in the section Pa, and detects whether or not the signal has a broadband distribution. Whether or not the distribution is broadband is detected based on, for example, whether or not the audio signal components are distributed over a band wider than a predetermined bandwidth.
Then, data representing the detection result is supplied to the microcomputer 13.

In this case, the section Pa in which the spectrum analysis section 12 performs the spectrum analysis gradually shifts by the interval τ in synchronization with the timing τ at which the attack detection output is taken into the microcomputer 13. . That is, the spectrum analyzer 12 always sets
The frequency distribution of the audio signal component in the section Pa up to the moment D + α before the instantaneous interruption section is detected.

The input analog audio signal Si is also supplied to the delay circuit 14 and delayed, and the analog audio signal Sid resulting from the delay is supplied to the switch circuit 1 for forming the instantaneous interruption section.
5 is supplied. The delay circuit 14 includes the attack detection unit 11
And the delay time required by the spectrum analyzer 12 is given to the input analog audio signal Si. That is, in this example, the input analog audio signal Si is delayed by the delay circuit 14 by the time that takes into account the operation time in the spectrum analysis unit 12 in addition to the time corresponding to the length of the section Pa. As described above, in the section Pa, the delay when the attack detection unit 11 detects an attack is already considered as the time α.

The switch circuit 15 is controlled on / off by the microcomputer 13. Switch circuit 15
Is normally turned on, but when a section that can be an instantaneous interruption section is detected as described later, the section P
It is turned off during the instantaneous interruption section formed in a. The microcomputer 13 determines from the detection output from the attack detection unit 11 that an attack has been detected for the input analog audio signal Si, and based on the analysis result of the spectrum analysis unit 12 for the section Pa immediately before the attack. When the section Pa is detected as having a wide band, the switch circuit 15 is turned off during the instantaneous interruption section formed in this section Pa, and an instantaneous interruption section is formed in the section Pa immediately before the attack. To do it.

In this way, the switch circuit 15 outputs a signal immediately before the attack detected by the attack detector 11 in a section where the audio signal component of the section has a wide band (not including the attack part). An analog audio signal So1 in which an instantaneous interruption section is formed is obtained.

The operation of FIG. 1 will be further described with reference to the waveform diagram of FIG.

That is, the input analog audio signal Si is
For example, if the signal is as shown in FIG. 2A (note that FIG. 2A shows the analog audio signal Sid delayed to match the timing), the attack detection unit 11 Attack ATK which suddenly rises and has a large amplitude is detected, for example, at time ta, and the detection result is supplied to the microcomputer 13.

At this time, the spectrum analyzer 12
(D + α) from the detection time ta of the attack ATK.
A spectrum analysis is performed on the audio signal component of the previous section Pa only, and a detection result indicating whether or not the section Pa has a wide band is supplied to the microcomputer 12. In this example, it is assumed that the detection result indicating that the band is wide is supplied to the microcomputer 12.

Then, the microcomputer 13 determines from the outputs of the attack detecting section 11 and the spectrum analyzing section 12 that the above-mentioned condition and the condition are satisfied, and switches the switch circuit 15 to the length D within the section Pa. Control is turned off in the section (see FIG. 2C).

The input analog audio signal Si is supplied to the delay circuit 1
4, the analog audio signal Sid
The switch circuit 15 is turned off in a section corresponding to the section to be detected as the instantaneous interruption section, and the section of the analog audio signal Sid is set to an alternating current as shown by a solid line in FIG. Becomes zero, and an instantaneous interruption section occurs.

FIG. 3 shows a processing routine of the microcomputer 13 for forming the instantaneous interruption section.
This processing routine is executed at each timing interval τ.

That is, the microcomputer 13
First, in step 101, the output of the attack detection unit 11 is monitored to determine whether an attack has been detected. If it is determined in step 101 that no attack has been detected, the process proceeds to step 105, where the switch circuit 15 is turned on. Then, this processing routine is terminated, and the next start timing is waited.

On the other hand, if it is determined in step 101 that an attack has been detected, the process proceeds to step 102, where the spectrum analysis result of the section Pa immediately before the detected attack is referred to, and the audio signal component of the section Pa is broadband. It is determined whether or not there is. As a result of the determination in step 102, when it is determined that the band is not a wide band but a narrow band, the process proceeds to step 105, the switch circuit 15 is kept on, and thereafter, this processing routine ends, and the next start timing is set. wait.

If it is determined in step 102 that the band is a wide band, the process proceeds to step 103, in which the switch circuit 15 is turned off for a time length D to be an instantaneous interruption section in the section Pa to form an instantaneous interruption section. I do. Then, the process proceeds to step 104, and after the instantaneous interruption section of the time length D is formed, the switch circuit 15 is turned on. Then, this processing routine is terminated, and the next start timing is waited.

The instantaneous interruption section can of course be formed not immediately before the attack section but after the attack section. However, as described above, when the instantaneous interruption section is formed immediately before the attack section, it is suitable for the instantaneous interruption section. It is easy to detect a section that has been set.

In the audio information transmission method according to the present invention, additional information is superimposed on an analog audio signal using the instantaneous interruption section formed as described above. Some embodiments of how to superimpose the additional information will be described below.

[First Embodiment of Method of Superimposing Additional Information] In the first embodiment, the time length D to be the instantaneous interruption section is set to a predetermined constant time length, for example, 1 ms. The additional information is inserted and superimposed in the section. In this case, the additional information to be superimposed has a broadband frequency distribution. The reason is that, as described above, the click sound becomes harder to hear as the bandwidth is wider.

In this embodiment, as the additional information to be superimposed, digital data which is spread spectrum is used. The signal on which the additional information is spread spectrum is a wideband signal. Therefore, even if this spread spectrum signal is superimposed on the instantaneous interruption section, the click sound can be suppressed and the sound quality deterioration can be suppressed to the minimum.

FIG. 4 shows a configuration example of the additional information superimposing circuit in the case of the first embodiment. FIG.
Is a time chart for explaining the operation.

In this example, a switching circuit 16 is provided in place of the switching circuit 15 in the example of FIG. 1, and the delayed analog audio signal Si from the delay circuit 14 is provided at one input terminal a. Enter Then, as shown in FIG. 5B, the microcomputer 13 switches the switch circuit 16 to the input terminal b side, thereby forming an instantaneous interruption section of the time length D in the analog audio signal Sid.

In the case of this example, when detecting an attack, the microcomputer 13 switches the digital data Sd as additional information to be superimposed on the audio signal, by switching the switch circuit 16 to the input terminal B side to make an instantaneous interruption period. The digital data Sd generated in the section of the power length D is transmitted to the modulator 1
7 In this example, the digital data Sd is one bit per time length D.

The modulator 17 spreads the digital data Sd. Spread spectrum is performed using a pseudo-noise code. In this example, the generation timing of the pseudo-noise code is synchronized with the attack detection timing. That is, the pseudo-noise code is reset at the attack detection timing. This is to make it possible to easily detect a pseudo-noise code for despreading. Then, the spectrum-spread additional information signal Ss from the modulator 17 is transmitted to the switch circuit 1.
6 is supplied to the input terminal b.

Therefore, from the switch circuit 16, as shown in FIG.
An audio signal So2 on which a signal Ss in which additional information is spread spectrum is superimposed is obtained.

The additional information thus superimposed is demodulated by the additional information demodulation circuit having the configuration shown in FIG.

That is, the analog audio signal So2 on which the additional information is superimposed as described above is
Thus, after the delay of the section Pa described above is performed, the signal is supplied to the switch circuit 22.

The analog audio signal So2 is also supplied to an attack detection unit 23 having the same configuration as the attack detection unit 11 in FIG.
And an attack portion is detected from the analog audio signal So2. Then, this attack detection unit 23
, A signal Tm indicating the attack detection time point is obtained, and this signal Tm is supplied to the extracted signal forming unit 24. From the extracted signal forming unit 24, only D whose time length is equal to the length of the instantaneous interruption section, A signal CT for turning on the switch circuit 22 is obtained, and the signal CT is supplied to the switch circuit 22.

The signal CT is a signal having a phase opposite to that of the switching control signal of the switch circuit 15 shown in FIG. 5B, and as can be seen from FIG. When the switch circuit 22 is turned on, the switch circuit 22 extracts and obtains additional information superimposed on the instantaneous interruption period, that is, additional information Ss that is spread spectrum. The extracted additional information Ss from the switch circuit 22 is supplied to a data demodulator 25, subjected to spectrum despreading processing, and returned to digital data Sd.

In this case, a signal Tm indicating the attack detection timing of the attack detection section 23 is also supplied to the data demodulator 24. The data demodulator 24 includes the same pseudo noise signal generator as the pseudo noise signal generator provided in the modulator 17. Based on the attack detection timing, the data demodulator 24 generates a pseudo noise signal for despreading and generates a reverse noise signal. Perform diffusion.
That is, in the case of this example, phase control such as a sliding correlator for despreading is unnecessary, a pseudo noise signal for despreading can be obtained quickly, and the data demodulation processing speed is high.

As described above, in the case of the first embodiment, the additional information superimposed on the instantaneous interruption section can be easily extracted from the analog audio signal by the extraction signal CT from the extraction signal forming unit 24. Can be. Further, since the instantaneous interruption section can be specified by the extraction signal CT, it is possible to easily cope with a case where the additional information needs to be rewritten, such as when the additional information is a generation-restricted duplication prevention control signal. .

In the above description, one bit of additional information is superimposed on one instantaneous interruption section. However, additional information of two or more bits can be superimposed. In addition, it is of course possible to superimpose a plurality of bits of additional information using a plurality of instantaneous interruption sections.

In the above-described example, the digital data is spectrum-spread using the pseudo noise signal to generate a superimposed signal. For example, by changing the phase of the pseudo noise signal in accordance with the digital data, The pseudo noise signal may be superimposed on the instantaneous interruption section to superimpose the additional information. For example, when the digital data is “0”,
When the digital data is “1”, the pseudo-noise signal having a zero phase is a superimposed signal, and the pseudo-noise signal having an inverted phase is a superimposed signal.

Instead of changing the phase of the pseudo-noise signal, it is also possible to prepare two different pseudo-noise signals and select them according to digital data.

In the above-described example, the time length of the instantaneous interruption section is set to a predetermined fixed length bet, but the time length of the instantaneous interruption section is changed according to the spread of the frequency distribution by spectrum analysis. You can also

The function of the extracted signal forming section 24 shown in FIG. 6 can be realized by software by a microcomputer.

[Second Embodiment of Method of Superimposing Additional Information] In the second embodiment, an instantaneous interruption is performed instead of inserting and superimposing additional information in an instantaneous interruption section as in the first embodiment. By changing the time length of the section in accordance with the digital data “1” and “0”, the digital additional information is superimposed on the analog audio signal.

In the case of the second embodiment, the hardware configuration for forming an instantaneous interruption section and superimposing additional information is as follows.
The configuration can be exactly the same as that of FIG. However, in the case of the second embodiment, the microcomputer 13
Is as shown in FIG.

That is, first, in step 201, the output of the attack detecting section 11 is monitored to determine whether or not an attack has been detected. If it is determined in step 201 that no attack has been detected, the process proceeds to step 207, where the switch circuit 15 is turned on. Then, this processing routine is terminated, and the next start timing is waited.

On the other hand, when it is determined in step 201 that an attack has been detected, the process proceeds to step 202, where the spectrum analysis result of the section Pa immediately before the detected attack is referred to, and the audio signal component of the section Pa is broadband. It is determined whether or not there is. As a result of the determination in step 202, when it is determined that the band is not a wide band but a narrow band, the process proceeds to step 207, the switch circuit 15 is kept on, and thereafter, this processing routine ends, and the next start timing is set. wait.

If it is determined in step 202 that the band is a wide band, the process proceeds to step 203, where it is determined whether the value of digital data to be superimposed as additional information is "1" or "0".

When the value of the digital data is "0", the process proceeds to step 204, and as shown in FIG.
In order to form an instantaneous interruption section with a relatively short time length D0 in the section Pa, the switch circuit 15 is operated during the time length D0.
Turn off. When the value of the digital data is "1", the process proceeds to step 205, and as shown in FIG. 8B, the time length D1 (D1> D0) longer than the time length D0 is set within the section Pa. The switch circuit 15 is turned off during the time length D1 so as to form an instantaneous interruption section.

After step 204 or step 205, the process proceeds to step 206, where the switch circuit 15 is turned on after an instantaneous interruption section of the time length D0 or the time length D1 is formed. Then, this processing routine is terminated, and the next start timing is waited.

Thus, in the case of the second embodiment,
By making the time length of the instantaneous interruption section different, one-bit additional information can be expressed in one instantaneous interruption section, and the additional information can be superimposed on the analog audio signal.

The additional information thus superimposed is demodulated by the additional information demodulation circuit having the configuration shown in FIG.

That is, the analog audio signal So3 on which the additional information is superimposed as described above is supplied to the delay circuit 31.
Thus, after the delay of the section Pa described above is performed, the signal is supplied to the instantaneous interruption time measuring unit 32. Analog audio signal So3
Is supplied to an attack detection unit 33 having the same configuration as the attack detection unit 11 in FIG. 1, and an attack portion is detected from the analog audio signal So3. Then, from the attack detection unit 33, a signal Tm indicating the time of the detection of the attack is obtained.
Supplied to

The instantaneous interruption time measuring section 32 measures the length of the instantaneous interruption section from the time of attack detection in the analog audio signal from the delay circuit 31 based on the signal Tm. And
The measurement time result, that is, the time length of the instantaneous interruption section is D0
Or D1 is supplied to the data analysis unit 34. The data analysis unit 34 restores the digital data that is the original additional information from the data of this time length.

As described above, in the case of the second embodiment, the additional information superimposed on the instantaneous interruption period can be easily demodulated from the analog audio signal. In addition, unlike the first embodiment, since the additional information is not spread and inserted and superimposed, the configuration of the additional information superimposing circuit and the demodulation circuit are simplified.

Also in this example, it is of course possible to superimpose additional information of a plurality of bits using a plurality of instantaneous interruption sections.

In addition, the ternary data can be superimposed by setting the time length of the instantaneous interruption section not to two as in the above example but to three.

[Third Embodiment of Method of Superimposing Additional Information] In the third embodiment, as in the second embodiment, additional information is not inserted in the momentary interruption section and superimposed. In the case of the example, the time point of the attack detection timing is used as a reference position,
By changing the distance from the reference position to the position of the instantaneous interruption section according to the digital data “1” and “0”, the digital additional information is superimposed on the analog audio signal. The attack detection peak value can be used as the reference attack detection time. Further, as described above, the time may be the time when the attack portion exceeds a predetermined level.

In the third embodiment, as in the second embodiment, the hardware configuration for forming an instantaneous interruption section and superimposing additional information is exactly the same as that of FIG. it can. However, in the case of the third embodiment, the processing routine in the microcomputer 13 is as shown in FIG.

That is, first, in step 301, the output of the attack detecting section 11 is monitored to determine whether or not an attack has been detected. If it is determined in step 301 that no attack has been detected, the process proceeds to step 307, where the switch circuit 15 is turned on. Then, this processing routine is terminated, and the next start timing is waited.

On the other hand, when it is determined in step 301 that an attack has been detected, the process proceeds to step 302, where the spectrum analysis result of the section Pa immediately before the detected attack is referred to, and the audio signal component of the section Pa is broadband. It is determined whether or not there is. As a result of the determination in step 302, when it is determined that the band is not a wide band but a narrow band, the process proceeds to step 307, the switch circuit 15 is kept on, and thereafter, this processing routine ends, and the next start timing is set. wait.

If it is determined in step 302 that the band is a wide band, the flow advances to step 303 to determine whether the value of digital data to be superimposed as additional information is "1" or "0".

When the value of the digital data is "0", the process proceeds to step 304, and as shown in FIG. 11 (A), within the section Pa, a predetermined time from the time T0 before the attack detection time ta to the time T0. Length D, for example 1ms
The switch circuit 15 is turned off during the time length D so as to form the instantaneous interruption section of. When the value of the digital data is “1”, the process proceeds to step 305, and as shown in FIG. 11B, in the section Pa, the time T1 (T1 ≠ T0, T1 ≠ T0) In this case, the switch circuit 15 is turned off during the time length D so that an instantaneous interruption section having a certain time length D is formed from a time point earlier by T1 <T0).

After step 304 or step 305, the process proceeds to step 306, where the switch circuit 15 is turned back on after the formation of the instantaneous interruption section of the time length D0 or the time length D1. Then, this processing routine is terminated, and the next start timing is waited.

Thus, in the case of the third embodiment,
By making the position of the instantaneous interruption section from the reference position different, one-bit additional information can be expressed by one instantaneous interruption section, and the additional information can be superimposed on the analog audio signal.

The additional information thus superimposed is demodulated by a circuit similar to the additional information demodulation circuit of the second embodiment shown in FIG. However, in the case of this example, instead of the instantaneous interruption time measurement unit 32, the attack detection time t
An instantaneous interruption position measuring unit that detects a difference in the position of the instantaneous interruption section with reference to a is used.

In the third embodiment, the same effects as in the second embodiment can be obtained.

Also in this example, it is of course possible to superimpose a plurality of bits of additional information using a plurality of instantaneous interruption sections.

In addition, the ternary data can be superimposed by setting the time length of the instantaneous interruption section not to two as in the above example but to three.

[Embodiment of Recording Apparatus] An example of a recording apparatus described below is a case where the above-described first embodiment is used as a method of superimposing additional information on an instantaneous interruption section. This is an example of a device that receives an analog audio signal that has been spread and superimposed thereon as an input signal, and records the signal. In the case of this example, the additional information is applied as the copy control information in the case of SCMS (Serial Copy Management System) performed by a digital audio interface.

Here, 2-byte data including a control code and a category code, or bit 2 called “C bit” in these 2 bytes,
Two bits of bit 15 called “L bit” are superimposed on the analog audio signal as additional information and transmitted.

“C bit” indicates the presence or absence of copyright protection, and “L bit” indicates generation information. In SCMS, recording of recorded software is permitted only for one generation.

FIG. 12 is a block diagram showing the configuration of the recording apparatus of this embodiment.

The analog audio signal Au input to the input terminal 40 of the recording apparatus of this example is the same as that of the second audio signal during the instantaneous interruption period.
There are cases where bit additional information is superimposed and cases where such additional information is not superimposed. The input analog audio signal Au is supplied to a recording processing unit 60 for recording on a recording medium through a delay circuit 41, a delay circuit 47, a switch circuit 48, and a switch circuit 49.

The delay circuits 41 and 47 are for timing adjustment. The switch circuit 48 is for rewriting the momentary interruption section on which the additional information is superimposed with new additional information, and is controlled by a switching control signal from the microcomputer 50 as described later. The switch circuit 49 is used for copy control. As will be described later, the switch circuit 49 is turned on when copying is permitted by a switching control signal from the microcomputer 50, and is turned off when copying is prohibited. .

The attack detecting section 43 has the same configuration as the attack detecting section 11 and the attack detecting section 23 of the above-described embodiment, and when an attack portion is detected in the input voice signal, a signal indicating the detection time point. Tm is supplied to the extraction signal forming unit 44 and to the microcomputer 50.

The extraction signal forming section 44 is similar to the extraction signal forming section 24 shown in FIG. 6, and forms a signal CT for extracting additional information superimposed on the input analog audio signal Au. It is supplied to the switch circuit 42. The switch circuit 42 is for extracting additional information.

The data demodulator 45 corresponds to the data demodulator 25 in the example of FIG. 6, and demodulates the demodulated data by inverse-spreading the spectrum-spread additional information extracted by the switch circuit 42 and demodulating the demodulated data. Computer 5
Supply 0.

The spectrum analyzer 46 has the same configuration as the spectrum analyzer 12 of FIG. 4, and detects the spread of the frequency band of the audio signal in the section Pa before the attack detection time point ta.

The data modulator 51 spectrum-spreads the additional information from the microcomputer 50 to be superimposed on the audio signal to be recorded and supplies it to the switch circuit 48.

The operation of the recording apparatus having the above configuration will be described below. First, a case where an analog audio signal Au in which additional information is superimposed in an instantaneous interruption period is supplied to the input terminal 40 will be described.

In this case, the analog audio signal Au input through the input terminal 40 is supplied to the switch circuit 42 after being delayed by the above-described section Pa by the delay circuit 41.

The analog audio signal Au is also supplied to an attack detection section 43 having the same configuration as the attack detection section 11 in FIG. 1, and an attack portion is detected from the analog audio signal Au. Then, a signal Tm indicating the time of the detection of the attack is obtained from the attack detecting section 43, and the signal Tm is supplied to the extracted signal forming section 44. D which is good
Only, a signal CT for turning on the switch circuit 42 is obtained, and this signal CT is supplied to the switch circuit 42.

As a result, the switch circuit 42 extracts and obtains additional information superimposed on the instantaneous interruption period, that is, additional information that is spread spectrum, and supplies it to the data demodulator 45. As described above, the data demodulator 45 performs the spectrum despreading process on the additional information to obtain 2-bit digital data. The 2-bit digital data is supplied to the microcomputer 50 and analyzed, and the input audio signal Au
Is determined as to whether or not there is copyright protection, and generation information is determined.

When the microcomputer 50 determines that there is no copyright protection as a result of the data analysis of the additional information, the switch circuit 48 switches the delay circuit 4 shown in FIG.
7 is selected, and the switch circuit 49 is turned on. Therefore, at this time,
The recording processing is performed by the recording processing unit 60, and the input audio signal Au is recorded on a recording medium, for example, a cassette tape.

The microcomputer 50 controls the switch circuit 49 to be off when it determines that the copyright protection is present and the generation information indicates that copying is prohibited as a result of the data analysis of the additional information. . Therefore, at this time, the audio signal Au is not supplied to the recording processing unit 60, and recording is prohibited.

Then, the microcomputer 50 determines that the copyright is protected as a result of the data analysis of the additional information,
If the generation information indicates that only one generation can be recorded, the switch circuit 49 is used to enable recording.
Is turned on. Then, the microcomputer 50
As additional information to be superimposed on the audio signal to be recorded, two bits, a bit indicating "copyright protected" and a bit indicating "copy prohibited" as generation information, are sent to the data demodulator 51 and the switch is switched. The circuit 48 is switched to a state in which the output signal of the data demodulator 51 is selected.

The data demodulator 51 spreads the spectrum of 2-bit additional information and supplies it to the switch circuit 48.

The delay circuit 47 adjusts the time so that the output timing of the additional information from the data demodulator 51 corresponds to the instantaneous interruption section in the audio signal Au. Therefore, the switch circuit 48 is switched to the data modulator 51 in the momentary interruption section in the audio signal Au, and the additional information is rewritten with new data. Then, an audio signal in which new additional information is superimposed on the momentary interruption section is supplied to the recording processing unit 60 via the switch circuit 49, and is recorded on a recording medium, for example, a cassette tape.

Next, a case where no additional information is superimposed on the input analog audio signal Au will be described.

In this case, the microcomputer 50
Detects that the additional information is not superimposed because the data cannot be obtained from the data demodulator 45 even if the signal Tm indicating the attack detection time is obtained from the attack detection unit 43. At this time, the microcomputer 50
Refers to the analysis result of the spectrum analysis unit 46, determines whether or not the audio signal in the section Pa has a wide band, and when it is in a wide band, switches the switch circuit 48 for the time length D , And at the same time as transmitting the additional information to be superimposed on the data modulator 51 at a timing corresponding to the time length D.

As the additional information, two bits of a bit indicating "copyright protected" and a bit indicating "copy prohibited" as generation information, or a bit indicating "copyright protected" and generation information , Or two bits that mean "only the first generation can be recorded".

Thus, an instantaneous interruption section is formed in the input audio signal, and additional information is superimposed on the instantaneous interruption section. Then, the audio signal on which the additional information is superimposed is supplied to the recording processing unit 60 through the switch circuit 49, and is recorded on the recording medium.

As described above, according to this recording apparatus, not only the additional information is superimposed on the audio signal, but also the additional information is rewritten.
It is possible to limit generations of duplication.

The above example is for the case where the additional information is copy protection control information.
Twelve-character code information called ISRC indicating the copyright holder recorded on a disk or the like may be superimposed. In this case, one bit or a plurality of bits are superimposed on one instantaneous interruption section, and the ISRC is dispersed and superimposed over a plurality of instantaneous interruption sections.

The recording medium recorded by illegal duplication using the copyright information can be traced.

As described above, when code information or the like having a large number of bits as a whole is to be dispersed and superimposed over a plurality of instantaneous interruption sections, when this can be repeatedly superimposed in voice information, For example, the additional information can be more easily extracted by superimposing specific information such that the head of the code information or the like can be identified as the head.

Further, the function of the extracted signal forming unit 44 in FIG. 12 is realized by software by the microcomputer 50, and the extracted signal forming unit 44 can be omitted.

[Other Modifications] The instantaneous interruption section formed in the audio signal is not limited to the section immediately before the attack section, but may be any section other than the attack section.

The spectrum analysis section in the spectrum analysis section does not need to have the same length as the section Pa.
A spectrum analysis may be performed on a wider section before the section Pa. In short, at least,
The spectrum analysis may be performed including the section Pa.

In the recording apparatus of the above-described example, an analog audio signal is recorded. However, as described above, when an analog audio signal on which additional information is superimposed using an instantaneous interruption section is converted to digital and recorded. Needless to say, the present invention is applicable.

[0117]

As described above, according to the present invention, additional information can be superimposed on an analog audio signal while minimizing deterioration of sound quality.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a main part of an embodiment of a voice information transmission method according to the present invention.

FIG. 2 is a time chart for explaining a main part of an embodiment of a voice information transmission method according to the present invention.

FIG. 3 is a flowchart illustrating a processing routine executed by a microcomputer 15 of FIG. 1;

FIG. 4 is a block diagram for explaining an embodiment of a voice information transmission method according to the present invention.

FIG. 5 is a time chart for explaining the operation of the embodiment of FIG. 4;

FIG. 6 is a block diagram of an example of an apparatus for demodulating additional information superimposed on an audio signal according to the present invention.

FIG. 7 is a flowchart for explaining a main part of another example of the embodiment of the audio information transmitting method according to the present invention.

FIG. 8 is a time chart for explaining the operation in the case of the example of FIG. 7;

9 is a block diagram of an example of an apparatus for demodulating additional information superimposed on an audio signal according to the example of FIG. 7;

FIG. 10 is a flowchart for explaining a main part of another example of the embodiment of the audio information transmitting method according to the present invention.

FIG. 11 is a time chart for explaining an operation in the case of the example of FIG. 10;

FIG. 12 is a block diagram of an example of a recording device to which the present invention is applied.

[Explanation of symbols]

11, 23, 33, 43 ... Attack detection unit, 12, 46
... Spectrum analysis unit, 13, 50 ... Microcomputer, 15, 16, 48 ... Switch circuit for forming instantaneous interruption section, 17, 51 ... Modulator for performing spread spectrum, 2
5, 44: a data demodulator that demodulates data by inverse spread spectrum; 22, 42: a switch circuit for extracting additional information; 49: a switch circuit for recording control;

Claims (8)

[Claims] An instantaneous interruption section having a time length that is difficult to hear as a click sound is provided in a section excluding a section of a sudden rise and a large amplitude of an audio signal and a section in which the component of the section is a narrow band. A voice information transmission method characterized by superimposing additional information on analog voice information using a section. 2. An attack detector for detecting a sudden rising and large amplitude portion of an audio signal, a spectrum analyzer for analyzing a spectrum of a section of the audio signal having a predetermined length, Output, from the output of the spectrum analysis unit, while removing the attack portion in the analog audio signal, the instantaneous interruption section forming means for providing an instantaneous interruption section in a wideband portion, formed by the instantaneous interruption section forming means Means for superimposing additional information using the instantaneous interruption section. 3. The audio information transmitting apparatus according to claim 2, wherein the instantaneous interruption section is a section temporally before the attack detected by the attack detection section. 4. The audio information transmitting apparatus according to claim 2, wherein the additional information is obtained by spectrum-spreading digital data, inserted into the instantaneous interruption section and superimposed. 5. The audio information transmitting apparatus according to claim 2, wherein the additional information is digital data and is represented by a difference in time length of the instantaneous interruption section. 6. The audio information transmitting apparatus according to claim 2, wherein the additional information is digital data, and is represented by a position of the instantaneous interruption section in the analog audio signal. 7. An attack detection unit for detecting a sudden rising and large amplitude portion of an input audio signal, and an addition superimposed from an output of the attack detection unit using an instantaneous interruption section formed in the input audio signal. Demodulation means for demodulating information; means for generating additional information to be newly superimposed on the instantaneous interruption section based on the additional information demodulated by the demodulation means; Means for superimposing on the input audio signal using a section. 8. The audio recording apparatus according to claim 7, wherein a spectrum analysis section for performing spectrum analysis on a section of a predetermined length of said input audio signal, an output of said attack detection section, and said spectrum analysis. From the output of the unit, the input voice signal, while removing the attack portion, and providing an instantaneous power cut section for providing an instantaneous power cut interval in a wideband portion; Means for superimposing the additional information of the audio recording device.