JP6995442B2 - Failure diagnostic equipment and method - Google Patents

Description

The present invention relates to a failure diagnosis device and a method for performing failure diagnosis of a speaker and a microphone installed in a vehicle interior or the like.

Conventionally, there has been known a speaker self-diagnosis device that detects an abnormality in a speaker by outputting a predetermined measurement signal from the speaker, collecting the sound with a microphone, and analyzing the sound (for example, Patent Document 1). reference.). In this self-diagnosis device, by using an M-sequence signal as a measurement signal, the measurement time is shortened and the discomfort in hearing is reduced as compared with the case where a loud impulse sound or a long-time sweep sound is used. ing.

Japanese Unexamined Patent Publication No. 2012-227857

By the way, in the self-diagnosis device disclosed in Patent Document 1 described above, since the measurement signal is output from the speaker and collected by the microphone, the speaker or the microphone is used in the normal operation (during the normal operation). ) Has a problem that an abnormality in a speaker or a microphone cannot be detected. In particular, in a configuration provided with a plurality of speakers, the user may not notice even if some of the speakers fail, and it is convenient if the abnormality of the speakers can be known in parallel with the normal operation. Further, although it is possible to detect an abnormality in the speaker by outputting the above-mentioned measurement signal from the speaker before and after the normal operation or by interrupting the normal operation, it takes time only for the measurement and the measurement is performed. Since the signal is a sound that has nothing to do with voice or music, there is a problem that the user may feel jarring. This point can be improved by using an M-sequence signal as a measurement signal, but it cannot be said to be a fundamental solution.

The present invention was created in view of these points, and an object thereof is to be able to detect an abnormality in a speaker or a microphone in parallel with normal operation, and no time is required only for detecting the abnormality. It is an object of the present invention to provide a failure diagnosis device and a method capable of preventing a user from feeling jarring.

In order to solve the above-mentioned problems, the failure diagnosis device of the present invention determines an acoustic signal output means for outputting an acoustic signal in which a watermark signal is embedded from a speaker to be diagnosed, and an acoustic signal output from the speaker. It is provided with a microphone that collects sound at the listening position of the speaker and an abnormality determining means for determining the presence or absence of an abnormality in the speaker based on a watermark signal embedded in an acoustic signal collected by the microphone.

Further, the failure diagnosis method of the present invention is to output an acoustic signal in which a watermark signal is embedded from a speaker to be diagnosed by an acoustic signal output means, and to output an acoustic signal output from the speaker to a microphone at a predetermined listening position. It has a function of collecting sound by means of a speaker and a method of determining the presence or absence of an abnormality in the speaker by an abnormality determining means based on a watermark signal embedded in an acoustic signal collected by a microphone.

In particular, it is desirable that the above-mentioned abnormality determining means determines that there is no abnormality in the speaker when the watermark signal can be detected, and determines that there is an abnormality in the speaker when the watermark signal cannot be detected. ..

Since the presence or absence of an abnormality in the speaker is determined using the watermark signal, the normal operation using the acoustic signal can be performed in parallel with the abnormality detection operation, and the time only for the abnormality detection becomes unnecessary. Further, since the watermark signal is embedded in the acoustic signal, the user does not have to be particularly conscious of the signal for detecting an abnormality, and it is possible to prevent the user from feeling jarring.

Further, it is desirable that the above-mentioned abnormality determining means determine that there is an abnormality in the microphone when the signal level of the acoustic signal collected by the microphone is equal to or less than a predetermined detection threshold value. This makes it possible to detect an abnormality in the microphone as well as an abnormality in the speaker.

Further, the above-mentioned speakers are a plurality of speakers, the acoustic signal output means outputs an acoustic signal in which different watermark signals are embedded at different timings from each of the plurality of speakers, and the abnormality determination means outputs an abnormality of the plurality of speakers. The presence or absence of is determined in parallel . As a result, even when the number of speakers increases, abnormalities of these plurality of speakers can be detected in parallel, and the time required for detection can be shortened.

Further, it is desirable that the watermark signal described above is generated by using the spectral diffusion method. In particular, it is desirable that the watermark signal described above is generated by multiplying predetermined data by pseudo-random number sequence data. As a result, it is possible to use a watermark signal in which signal components are dispersed in a wide frequency band, and it is possible to further prevent the user from feeling jarring about the components of a specific frequency.

Further, it is desirable that the acoustic signal storage means for storing the acoustic signal in which the watermark signal is embedded is further provided, and the acoustic signal output means reads the acoustic signal from the acoustic signal storage means and outputs the acoustic signal from the speaker. In particular, it is desirable that the above-mentioned acoustic signal storage means is prepared in advance and stores an acoustic signal whose contents do not change each time it is read. This makes it possible to prepare in advance an acoustic signal suitable for detecting an abnormality in the speaker.

Further, the embedding target acoustic signal as the acoustic signal before the above-mentioned watermark signal is embedded is input, and the embedding suitability determination means for determining the suitability of embedding the watermark signal and the embedding suitability determination means are suitable for embedding the watermark signal. It is further desirable to provide an acoustic signal creating means for creating an acoustic signal by embedding a watermark signal in the embedded target acoustic signal determined to be. This makes it possible to select an acoustic signal suitable for embedding a watermark signal from the acoustic signals used in normal operation each time.

Further, it is desirable that the above-mentioned embedding suitability determination means determines that it is suitable for embedding a watermark signal when a signal component of a predetermined level or higher is present in the entire audible band. This makes it possible to reliably mask the watermark signal used for failure diagnosis.

It is a figure which shows the schematic structure of the failure diagnosis apparatus of one Embodiment. It is a figure which shows the relationship between the opening sound and the embedding position of a watermark signal. It is a figure which shows the process of embedding a watermark signal in an opening sound. It is a figure which shows the embedding position of the watermark signal in the opening sound which reached the microphone. It is a figure which shows the outline of the data restoration by a decoding processing part. It is a figure which shows the modification of the failure diagnosis apparatus. It is a figure which shows the other modification of the failure diagnosis apparatus. It is a figure which shows the structure which embeds a watermark signal in an audio sound.

Hereinafter, a failure diagnosis device according to an embodiment to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a failure diagnosis device according to an embodiment. As shown in FIG. 1, the failure diagnosis device to which the present invention is applied includes an opening (OP) sound output unit 100, a speaker 110, a microphone 150, a watermark signal detection unit 160, and an abnormality determination unit 170. The opening sound output unit 100 corresponds to the acoustic signal output means, and the watermark signal detection unit 160 and the abnormality determination unit 170 correspond to the abnormality determination means.

This failure diagnosis device constitutes a part of an in-vehicle device mounted on a vehicle, and the opening sound output unit 100, the speaker 110, and the microphone 150 are used for purposes other than the failure diagnosis of the speaker. It is also used for failure diagnosis.

The opening sound output unit 100 outputs a predetermined opening sound. For example, this opening sound is a sound or effect that is output at the same time as the initial screen display at startup in an in-vehicle device including a navigation device and an audio device when the accessory switch of the vehicle is turned on and the power is turned on. When using sound, it is assumed that an acoustic signal whose content does not change each time it is output is used, such as when using a sound output from an ETC on-board unit indicating whether or not an ETC card is inserted. Further, a watermark signal is embedded in the opening sound in advance.

As the watermark signal, for example, a watermark signal corresponding to the "spectral diffusion method" described in the following documents can be used.

Akira Nishimura, "Technology for Concealing Information on Acoustic Signals", Journal of the Acoustical Society of Japan, Vol. 63, No. 11, (2007), p. 660-667
In particular, the above-mentioned opening sound has a known (fixed) content, and instead of the opening sound that has been conventionally used, an opening sound with a watermark signal embedded is prepared and stored and stored. All that is required is to read the opening sound and output it from the speaker 110. Further, since the watermark signal created by the above-mentioned spectral diffusion method is diffused over a wide frequency range, at least the watermark signal is embedded in order to mask such a watermark signal and make it invisible to the user. For the location, it is also necessary to select an opening sound that has a frequency component over a wide frequency range.

FIG. 2 is a diagram showing the relationship between the opening sound and the embedding position of the watermark signal. The horizontal axis shows the elapsed time t, and the vertical axis shows the signal level of the opening sound. Further, the output start time of the opening sound is t1, the output completion time of the opening sound is t4, the output start time of the embedded watermark signal having a predetermined time length is t2, and the output completion time of the watermark signal is t3. ..

By the way, as described above, since the opening sound output by the opening sound output unit 100 has a watermark signal embedded in advance, it is not necessary to embed the watermark signal each time, but the opening sound collected by the microphone 150. In order to make the process of extracting the watermark signal from the sound easier to understand, first, the process of embedding the watermark signal in the opening sound will be briefly described.

FIG. 3 is a diagram showing a process of embedding a watermark signal in the opening sound. After multiplying a predetermined number of bits of data (for example, data for identifying the speaker 110) with a pseudo-random number sequence that is a key for signal diffusion and decoding with a multiplier 10 to generate a watermark signal. , The level is adjusted by the level adjuster 12 so as to be masked by the opening sound, and the opening sound is added by the adder 14. In this way, the opening sound (FIG. 2) on which the diffused watermark signal is superimposed is created. For example, the input data represents bit information with an amplitude of 1 or -1 for every 8 samples, and if the number of bits of the data is 6, and the data rate length of 1 bit is 50 ms for 8 samples, 6 bits. The total data is 48 samples, and the embedding time length of the watermark signal is 300 ms. The pseudo-random number sequence is assigned 1 or -1 for each sample, and the multiplier 10 multiplies the data and the pseudo-random number sequence in sample units.

The opening sound created in this way is stored in the opening (OP) sound storage unit 16. The opening sound output unit 100 shown in FIG. 1 reads out the opening sound after the watermark signal is embedded from the opening sound storage unit 16 and outputs it from the speaker 110. The opening sound storage unit 16 described above corresponds to the acoustic signal storage means.

Further, the speaker 110 and the microphone 150 are arranged at predetermined positions in the acoustic space. For example, when it is assumed that the equalizer device or the active noise canceller (ANC) is used, the speaker 110 connected to these devices or the microphone 150 provided near the listening position of the user is used as it is. Alternatively, when performing a failure diagnosis of a plurality of speakers in an audio device or the like, the speaker 110 connected to the audio device or the microphone 150 provided near the listening position of the user is used as it is.

The watermark signal detection unit 160 detects the watermark signal embedded in the opening sound collected by the microphone 150. For this purpose, the watermark signal detection unit 160 includes a cross-correlation calculation unit 161, a watermark embedding position determination unit 162, and a decoding processing unit 163.

The cross-correlation calculation unit 161 calculates the cross-correlation between the collected opening sound output from the microphone 150 and the pseudo-random number sequence used to create the watermark signal embedded in the opening sound. As described above, when the watermark signal consists of bit data of 48 samples, the correlation value for the 48 samples is calculated while shifting the target portion of the opening sound by one sample.

The watermark embedding position determination unit 162 determines the target location where the correlation value calculated by the cross-correlation calculation unit 161 is maximum as the watermark embedding position for the opening sound.

FIG. 4 is a diagram showing the embedding position of the watermark signal in the opening sound reaching the microphone 150. In FIG. 4, OP1 is an opening sound output from the speaker 110, which is the same as that shown in FIG. The output of the opening sound OP1 is started from the speaker 110 at the time of t1, and the output of the watermark signal is started at the time of t2. After that, the output of the watermark signal is completed at the time of t3, and the output of the opening sound OP1 is completed at the time of t4. Assuming that the delay time of the acoustic signal from the speaker 110 to the microphone 150 is T, the opening sound OP1 in which the watermark signal is embedded reaches the microphone 150 with a delay of time T after being output from the speaker 110.

In FIG. 4, OP2 is an opening sound that is collected and output from the microphone 150. This opening sound OP2 starts at t11 (= t1 + T) and ends at t14 (= t4 + T). On the other hand, the watermark signal embedded in the opening sound OP2 starts at the time of t12 (= t2 + T) and ends at the time of t13 (= t3 + T).

Since the cross-correlation calculated by the cross-correlation calculation unit 161 described above becomes maximum at the time of t13 when the output of the watermark signal is completed, the watermark embedding position determination unit 162 determines this t13 as the watermark signal embedding position. ..

The decoding processing unit 163 restores the data (data that identifies the speaker 110) included in the embedded watermark signal based on the collected opening sound output from the microphone 150.

FIG. 5 is a diagram showing an outline of data restoration by the decoding processing unit 163. As described above, when the watermark signal embedding position determination unit 162 determines the time when the watermark signal capture is completed (time t13), the watermark in the opening sound input to the microphone 150 is based on that time. The location corresponding to the signal can be identified. The adder 20 assumes that the first opening sound of the identified location (for example, the opening sound output from the microphone 150 is temporarily stored in a storage unit (not shown) and can be read out after the relevant location is identified. ), The watermark signal embedded in the opening sound is extracted by subtracting the second opening sound without the watermark signal corresponding to the same position. The multiplier 21 multiplies the extracted watermark signal by the pseudo-random number sequence used to create the watermark signal, thereby performing despreading processing for spectral diffusion and restoring the data. In reality, when each bit of the data is represented by 8 samples, the data of a predetermined number of bits is restored by averaging the amplitudes at each data rate corresponding to the 8 samples. ..

The abnormality determination unit 170 determines the presence or absence of an abnormality in each of the speaker 110 and the microphone 150. Specifically, the abnormality determination unit 170 determines that there is no abnormality in the microphone 150 when the signal level of the opening sound collected by the microphone 150 exceeds a predetermined detection threshold value, and conversely, a signal. When the level is equal to or lower than a predetermined detection threshold value, it is determined that the microphone 150 has an abnormality. Further, when the abnormality determination unit 170 can detect the watermark signal embedded in the opening sound output from the speaker 110 by the watermark signal detection unit 160 (when the data for identifying the speaker 110 is output from the decoding processing unit 163). ), It is determined that there is no abnormality in the speaker 110, and conversely, when the watermark signal cannot be detected, it is determined that there is an abnormality in the speaker 110.

As described above, in the failure diagnosis device of the present embodiment, since the presence or absence of an abnormality in the speaker 110 or the like is determined using the watermark signal, the normal operation using the opening sound can be performed in parallel with the abnormality detection operation. , Time is not required just for abnormality detection. Further, since the watermark signal is embedded in the acoustic signal, the user does not have to be particularly conscious of the signal for detecting an abnormality, and it is possible to prevent the user from feeling jarring.

Further, when the signal level of the opening sound collected by the microphone 150 or the like is equal to or less than a predetermined detection threshold value, it is determined that the microphone 150 or the like has an abnormality. In this way, it is possible to detect an abnormality of the microphone 150 or the like as well as an abnormality of the speaker 110 or the like.

Further, using the spectral diffusion method, specifically, a watermark signal in which signal components are dispersed in a wide frequency band can be used by generating a watermark signal by multiplying predetermined data by pseudo-random number sequence data. This makes it possible to further prevent the user from feeling jarring about the components of a specific frequency.

FIG. 6 is a diagram showing a modified example of the failure diagnosis device. The failure diagnosis device shown in FIG. 6 is for determining the presence or absence of abnormalities in the two speakers 110A and 110B and the two microphones 150A and 150B, respectively, and has two opening sound output units 100A and 100B and four. A watermark signal detection unit 160A, 160B, 160C, 160D and an abnormality detection unit 170A are provided.

On the other hand, the opening sound output unit 100A outputs the opening sound OP-A in which the watermark signal A is embedded from the speaker 110A. Further, the other opening sound output unit 100B outputs the opening sound OP-B in which the watermark signal B is embedded from the speaker 110B. These two watermark signals A and B are set so as to be offset so that their embedded positions do not overlap. The watermark signal A and the watermark signal B are different in the content of the data input to the multiplier 10 shown in FIG. 3, and are different in the content of the pseudo-random number sequence used for creating the watermark signals A and B. ..

The watermark signal detection unit 160A detects the watermark signal A embedded in the opening sound OP-A collected by one of the microphones 150A. The watermark signal detection unit 160B detects the watermark signal B embedded in the opening sound OP-B collected by one of the microphones 150A. The watermark signal detection unit 160C detects the watermark signal A embedded in the opening sound OP-A collected by the other microphone 150B. The watermark signal detection unit 160D detects the watermark signal B embedded in the opening sound OP-B collected by the other microphone 150B.

The abnormality determination unit 170A determines the presence or absence of an abnormality in the speakers 110A and 110B and the microphones 150A and 150B, respectively. Specifically, the abnormality determination unit 170A has no abnormality in the microphone 150A when at least one of the signal levels of the opening sounds OP-A and OP-B collected by the microphone 150A exceeds a predetermined detection threshold value. On the contrary, when the signal levels of both the opening sounds OP-A and OP-B are equal to or lower than the predetermined detection threshold value, it is determined that the microphone 150A has an abnormality. Further, the abnormality determination unit 170A determines that there is no abnormality in the microphone 150B when the signal level of at least one of the opening sounds OP-A and OP-B collected by the microphone 150B exceeds a predetermined detection threshold value. On the contrary, when the signal levels of both the opening sounds OP-A and OP-B are equal to or less than the predetermined detection threshold value, it is determined that the microphone 150B has an abnormality.

Further, the abnormality determination unit 170A determines that there is no abnormality in one of the speakers 110A when the watermark signal A can be detected by the watermark signal detection units 160A and 160C when the two microphones 150A and 150B have no abnormality. When the watermark signal B can be detected by the watermark signal detection units 160B and 160D, it is determined that there is no abnormality in the other speaker 110B.

When the abnormality determination unit 170A has no abnormality in one microphone 150A and the other microphone 150B has an abnormality, the abnormality determination unit 170A switches to one speaker 110A when the watermark signal A can be detected by the watermark signal detection unit 160A. It is determined that there is no abnormality, and when the watermark signal B can be detected by the watermark signal detection unit 160B, it is determined that there is no abnormality in the other speaker 110B. Further, when the abnormality determination unit 170A has an abnormality in one of the microphones 150A and the other microphone 150B has no abnormality, the abnormality determination unit 170A determines the one speaker 110A when the watermark signal A can be detected by the watermark signal detection unit 160C. It is determined that there is no abnormality, and when the watermark signal B can be detected by the watermark signal detection unit 160D, it is determined that there is no abnormality in the other speaker 110B. Further, if there is an abnormality in both the microphones 150A and 150B, it is not possible to determine the presence or absence of the abnormality in the speakers 110A and 110B.

In this way, even when the number of speakers and microphones increases, abnormalities in these speakers 110A and 110B and microphones 150A and 150B can be detected in parallel, and the time required for detection can be shortened. can.

FIG. 7 is a diagram showing another modification of the failure diagnosis device. The failure diagnosis device shown in FIG. 7 is for determining the presence or absence of abnormalities in the two speakers 110A and 110B and the two microphones 150A and 150B, respectively, and the two opening sound output units 100A and 100B and the two. It includes watermark signal detection units 160A and 160B, abnormality detection units 170B, two changeover switches 180 and 182, and a control unit 190.

In this failure diagnosis device, by switching the two changeover switches 180 and 182 in order by the control unit 190, the microphone 150A is connected to the watermark signal detection unit 160A at the time of the output of the first opening sound to detect the watermark signal A. Then, when the second opening sound is output, such as at the next startup, the microphone 150A is connected to the watermark signal detection unit 160B to detect the watermark signal B, and similarly, the microphone 150B is watermarked when the third opening sound is output. The watermark signal A is detected by connecting to the signal detection unit 160A, and the microphone 150B is connected to the watermark signal detection unit 160B to detect the watermark signal B at the time of outputting the opening sound for the fourth time. By detecting the watermark signals A and B in four steps in this way, the same detection results as those of the four watermark signal detection units 160A, 160B, 160C and 160D shown in FIG. 6 can be obtained. Thereby, the abnormality determination unit 170B can determine the presence / absence of the abnormality of the speakers 110A and 110B and the microphones 150A and 150B in the same manner as the abnormality determination unit 170A shown in FIG.

Further, since the number of watermark signal detection units 160A and the like can be reduced, it is possible to suppress an increase in the processing load for abnormality detection even when the number of speakers and microphones increases.

Further, the present invention is not limited to the above embodiment, and various modifications can be carried out within the scope of the gist of the present invention. For example, in the above-described embodiment, the case where the number of speakers or microphones is 1 or 2 has been described, but the case may be 3 or more.

Further, in the above-described embodiment, the case of performing the failure diagnosis of the speaker 110 and the microphone 150 used in the in-vehicle device mounted on the vehicle has been described, but the failure diagnosis of the speaker or the microphone arranged in the acoustic space other than the vehicle is performed. The present invention may be applied to such cases.

Further, in the above-described embodiment, the opening sound having a fixed content is used in advance, but a watermark signal is embedded by using an acoustic signal whose content changes, such as an audio sound output from an audio device, to be used in a speaker or a microphone. Failure diagnosis may be performed.

FIG. 8 is a diagram showing a configuration in which a watermark signal is embedded in an audio sound. In the configuration shown in FIG. 8, an audio sound buffer 30, a spectrum analysis unit 31, an embedded range setting unit 32, an audio sound extraction unit 33, and a watermark signal synthesis unit 34 are added to the configuration shown in FIG. The spectrum analysis unit 31 and the embedding range setting unit 32 correspond to the embedding suitability determination means, and the multiplier 10, the level adjuster 12, the adder 14, the audio sound extraction unit 33, and the watermark signal synthesis unit 34 correspond to the acoustic signal creation means, respectively. ..

The audio sound buffer 30 temporarily stores the audio sound before being output from the speaker 110 or the like. The spectrum analysis unit 31 performs spectrum analysis on the audio sound stored in the audio sound buffer 30. Based on the analysis result of the spectrum analysis unit 31, the embedding range setting unit 32 sets the range of the audio sound in which the signal component of the predetermined level or higher exists in the entire audible band as the embedding range of the watermark signal. As described above, since the watermark signal created by the spectral diffusion method is spread over a wide frequency range, in order to mask such a watermark signal, the audio sound in which the watermark signal is embedded is also a signal component over a wide frequency range. Must have. The spectrum analysis unit 31 and the embedded range setting unit 32 are for extracting a part of the audio sound suitable for such an application. Even if the condition that a signal component of a predetermined level or higher is present in the entire audible band is not satisfied, the watermark signal may be set as an embedded range.

The audio sound extraction unit 33 extracts a partial audio sound corresponding to the embedding range of the watermark signal set by the embedding range setting unit 32 from the audio sound buffer 30. This partial audio sound is input to the adder 14, and the watermark signal output from the level adjuster 12 is embedded in this partial audio sound. The watermark signal synthesizing unit 34 performs an audio sound synthesis process of replacing the partial audio sound in which the watermark signal is embedded with the audio sound before the watermark signal is embedded. The audio sound after the watermark signal is embedded by this synthesis process is read out from the audio sound buffer 30 and output from the speaker 110.

By embedding the watermark signal in the audio sound or the like in this way, it becomes possible to select a sound signal suitable for embedding the watermark signal from the acoustic signals used in normal operation each time.

As described above, according to the present invention, since the presence or absence of an abnormality in the speaker is determined using the watermark signal, the normal operation using the acoustic signal can be performed in parallel with the abnormality detection operation, and the abnormality detection can be performed. You don't need time just for the sake of it. Further, since the watermark signal is embedded in the acoustic signal, the user does not have to be particularly conscious of the signal for detecting an abnormality, and it is possible to prevent the user from feeling jarring.

100, 100A, 100B Opening sound output unit 110, 110A, 110B Speaker 150, 150A, 150B Microphone 160, 160A, 160B, 160C, 160D Watermark signal detection unit 161 Cross-correlation calculation unit 162 Watermark embedding position determination unit 163 Decoding processing unit 170 , 170A, 170B Abnormality determination unit 180, 182 Changeover switch 190 Control unit

Claims (10)

An acoustic signal output means that outputs an acoustic signal in which a watermark signal is embedded from a speaker to be diagnosed,
A microphone that collects the acoustic signal output from the speaker at a predetermined listening position, and
An abnormality determining means for determining the presence or absence of an abnormality in the speaker based on the watermark signal embedded in the acoustic signal collected by the microphone.
The speaker is a plurality of speakers.
The acoustic signal output means outputs an acoustic signal in which different watermark signals are embedded at different timings from each of the plurality of speakers.
The abnormality determination means is a failure diagnosis device, characterized in that the presence or absence of an abnormality in a plurality of the speakers is determined in parallel . The abnormality determining means determines that there is no abnormality in the speaker when the watermark signal can be detected, and determines that there is an abnormality in the speaker when the watermark signal cannot be detected. The failure diagnosis device according to claim 1. The abnormality determination means according to claim 1 or 2, wherein the abnormality determination means determines that there is an abnormality in the microphone when the signal level of the acoustic signal collected by the microphone is equal to or less than a predetermined detection threshold value. Failure diagnosis device. The failure diagnosis device according to any one of claims 1 to 3 , wherein the watermark signal is generated by using a spectral diffusion method. The failure diagnosis device according to claim 4 , wherein the watermark signal is generated by multiplying predetermined data by pseudo-random number sequence data. Further provided with an acoustic signal storage means for storing the acoustic signal in which the watermark signal is embedded,
The failure diagnosis device according to any one of claims 1 to 5 , wherein the acoustic signal output means reads the acoustic signal from the acoustic signal storage means and outputs the acoustic signal from the speaker. The failure diagnosis device according to claim 6 , wherein the acoustic signal storage means is prepared in advance and stores the acoustic signal whose contents do not change each time it is read. An embedding suitability determination means for determining the adequacy of embedding of the watermark signal by inputting an embedding target acoustic signal as an acoustic signal before the watermark signal is embedded.
An acoustic signal creating means for embedding the watermark signal in the embedding target acoustic signal determined to be suitable for embedding the watermark signal by the embedding suitability determination means, and an acoustic signal creating means for creating the acoustic signal.
The failure diagnosis device according to any one of claims 1 to 5 , further comprising. The failure according to claim 8 , wherein the embedding suitability determination means determines that the watermark signal is suitable for embedding when a signal component of a predetermined level or higher is present in the entire audible band. Diagnostic device. Outputting an acoustic signal with an embedded watermark signal from the speaker to be diagnosed by the acoustic signal output means, and
Collecting the acoustic signal output from the speaker with a microphone at a predetermined listening position,
Based on the watermark signal embedded in the acoustic signal collected by the microphone, the presence or absence of an abnormality in the speaker is determined by an abnormality determining means.
The speaker is a plurality of speakers.
The acoustic signal output means outputs an acoustic signal in which different watermark signals are embedded at different timings from each of the plurality of speakers.
The abnormality diagnosing means is a failure diagnosis method, characterized in that the presence or absence of an abnormality in a plurality of the speakers is determined in parallel .

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