JP2002159098A - Microphone unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microphone unit in which failure of a microphone can be detected. SOLUTION: An output signal from a microphone 2 is inputted to an amplifier 6 and an amplified signal is delivered to a DSP 7. The DSP 7 comprises a signal processing section 7a and a failure diagnosing section 7b and the amplified signal is inputted to the signal processing section 7a and the failure diagnosing section 7b. In the DSP 7, failure diagnosis of the microphone 2 is performed at the failure diagnosing section 7b based on the amplified signal. More specifically, voltage variation value of the amplified signal is calculated at the failure diagnosing section 7b. If the voltage variation value falls within a threshold preset in the DSP 7, a decision is made that the microphone 2 has failed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone device.

[0002]

2. Description of the Related Art In general, there is known a voice recognition device for operating a vehicle electrical component such as a car navigation by voice. In such a voice recognition device, a microphone device is used as a voice detection device.

Conventionally, a microphone device detects an operator's voice using one or more microphones. When a voice is detected by the microphone, the voice is converted into an electrical voice signal and output to the voice recognition device. Therefore, the voice recognition device operates based on this voice signal.

[0004]

However, in the conventional microphone device, when the microphone device breaks down due to, for example, aging or the impact of a vehicle accident or the like, the operator or the voice recognition device does so. Could not figure out. For this reason, even if the operator cannot operate the voice recognition device due to the malfunction of the microphone device, the operator cannot grasp which of the devices is malfunctioning.

In a microphone device provided with a microphone array composed of a plurality of microphones, an output signal having high directivity is output to a speech recognition device by processing an output signal from each microphone. ing. However, in the related art, since a failure of a microphone cannot be grasped, if even one of the microphones fails, signal processing including an output signal from the failed microphone is performed. Therefore, in spite of the presence of a normal microphone, the microphone device may not function as a voice detection device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a microphone device capable of detecting a failure of a microphone.

[0007]

In order to solve the above problems, according to the first aspect of the present invention, a microphone,
The gist of the invention is to provide a failure diagnosis means for monitoring an output signal from the microphone and diagnosing whether or not the microphone has failed based on the output signal.

According to a second aspect of the present invention, in the microphone device according to the first aspect, the failure diagnosing means determines whether a voltage fluctuation value of an output signal from the microphone is lower than a predetermined threshold value. The gist is to diagnose that the microphone is out of order.

According to a third aspect of the present invention, in the microphone device according to the first aspect, the microphone device includes a power supply for applying a predetermined potential to the microphone and a resistor, and the failure diagnosis means includes: Changing the resistance value of the resistor, the degree of the characteristic change of the output signal of the microphone accompanying the change,
The gist of the present invention is to compare the degree of characteristic fluctuation of the output signal during normal operation of the microphone and to perform a failure diagnosis of the microphone based on the comparison result.

According to a fourth aspect of the present invention, in the microphone device according to the first aspect, the failure diagnosis means applies an AC signal of a predetermined frequency to a signal line of the microphone and outputs a result. The gist of the present invention is to compare the characteristics of the output signal of the microphone with the characteristics of the AC signal and perform a failure diagnosis of the microphone based on the comparison result.

According to a fifth aspect of the present invention, in the microphone device according to the first aspect, the failure diagnosis means sets a signal component having a predetermined voltage value or more in an output signal from the microphone as a desired signal component. At the same time, a signal component less than the predetermined voltage value is set as a noise component, and if the S / N ratio based on the signal component exceeds a predetermined S / N ratio, it is determined that the microphone is out of order. The point is to do.

According to a sixth aspect of the present invention, in the microphone device according to the first or fifth aspect, the failure diagnosis means activates an external device to which a processing signal processed by the microphone device is input. When the operating means is operated, the output signal from the microphone is monitored for a predetermined period of time, and a state in which the S / N ratio of the output signal is lower than a predetermined S / N ratio is continuously performed for a predetermined number of times. The gist of the present invention is to judge that the microphone is out of order when the microphone is detected.

According to a seventh aspect of the present invention, in the microphone device according to any one of the first to sixth aspects, the microphone device includes amplifying means for amplifying an output signal from the microphone, The failure diagnosis unit monitors the characteristics of the output signal on the input side of the amplification unit, diagnoses the microphone based on the characteristics, and monitors the characteristics of the amplified signal output from the amplification unit. When the amplification factor for each frequency component of the amplified signal with respect to the output signal on the input side of the amplification device is different from the amplification factor for each frequency component during normal operation of the amplification device, the amplification device fails. The gist is to judge that there is

According to an eighth aspect of the present invention, in the microphone device according to any one of the first to sixth aspects, the microphone device includes amplifying means for amplifying an output signal from the microphone, The failure diagnosing means includes a predetermined frequency AC
While applying the signal, the amplified signal output from the amplifying means is monitored, the characteristic of the amplified signal is compared with the characteristic of the AC signal, and the failure diagnosis of the amplifying means is performed based on the comparison result. That is the gist.

Hereinafter, the "action" of the present invention will be described. According to the first aspect of the present invention, the output signal from the microphone is monitored by the failure diagnosis unit, and it is diagnosed based on the output signal whether the microphone is out of order.

According to the second aspect of the present invention, the failure diagnosis means determines that the microphone has failed when the voltage fluctuation value of the output signal from the microphone is lower than a predetermined threshold value. to decide. For this reason,
For example, if the threshold is set equal to the voltage fluctuation value due to the lowest level of possible vehicle noise, it is possible to detect that the microphone is not functioning even if nothing is input to the microphone Becomes

According to the third aspect of the present invention, when the resistance value of the resistor is changed, the voltage level and the frequency characteristic of the output signal of the microphone are changed accordingly. Then, even if the characteristics of the output signal during normal operation and at the time of failure of the microphone are, for example, approximated at a certain resistance value, if the resistance value is changed, the degree of the characteristic fluctuation tends to be different. For this reason, by performing the failure diagnosis of the microphone based on the degree of the characteristic variation, the failure diagnosis can be performed with higher accuracy.

According to the fourth aspect of the invention, by applying an AC signal of a predetermined frequency to the signal line of the microphone, an output signal corresponding to the AC signal is output from the microphone. In other words, the microphone
It will be in a state of pseudo operation. In addition, if the microphone is normal, the frequency component of the output signal output from the microphone becomes substantially equal to the frequency of the AC signal. Therefore, the failure diagnosis means can diagnose the failure of the microphone by diagnosing whether at least the frequency of the AC signal matches the frequency of the output signal and comparing the voltage fluctuation.

According to the fifth aspect of the present invention, the failure diagnosing means sets the S / N ratio of the output signal from the microphone to:
When the signal exceeds a predetermined S / N ratio, it is determined that the microphone is out of order. That is, the failure diagnosis unit determines that the microphone has failed when the ratio of the signal component having the predetermined voltage value or more in the output signal is too high. For this reason, the failure diagnosis unit determines that the microphone has failed even if the microphone has moved to a place with a bad noise environment, such as in an engine room. That is, the failure diagnosis unit determines that the microphone has failed even when a signal component that should be originally recognized as a noise component has been recognized as a desired signal component.

According to the sixth aspect of the present invention, the failure diagnosing means determines that the S / N ratio of the output signal from the microphone when the operating means is operated is lower than the predetermined S / N ratio. When the number of detections is detected consecutively, it is determined that the microphone is out of order. That is, the failure diagnosis unit performs the failure diagnosis based on an output signal when a positive operation for making the microphone function is performed. Therefore, the failure diagnosis of the microphone is performed with higher accuracy.

According to the seventh aspect of the present invention, the microphone device is provided with the amplification means, and the failure diagnosis means is provided with:
The failure diagnosis of the amplification means is performed together with the failure diagnosis of the microphone. Therefore, when the microphone device including the amplifying unit fails, it is possible to easily grasp whether the microphone has failed or the amplifying unit has failed.

According to the eighth aspect of the present invention, the failure diagnosing means applies an AC signal of a predetermined frequency to the input side of the amplifying means at the time of failure diagnosis, and outputs an amplified signal from the amplifying means based on the AC signal. The failure diagnosis of the amplification means is performed by monitoring. Since the AC signal has only one frequency component, if the amplifying means is normal, the amplified signal also has only that frequency component. Therefore, the failure diagnosis unit can easily and reliably perform the failure diagnosis of the amplification unit.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in a vehicle microphone device will be described in detail with reference to FIG.

The microphone device 1 includes a microphone 2, a pull-up resistor 3, a DC power supply 4, a coupling capacitor 5, an amplifier 6 as amplifying means, and a digital signal processor (DSP) 7.

The microphone 2 is an electret microphone including a diaphragm 2a, a fixed electrode 2b, and an n-channel FET 2c. In the present embodiment, the microphone 2 is provided on a steering wheel. The source terminals of the diaphragm 2a and the FET 2c are grounded, and the fixed electrode 2b is connected to the gate terminal of the FET 2c. The drain terminal of the FET 2c is connected to one end of the pull-up resistor 3 and the input terminal of the amplifier 6 via the coupling capacitor 5. The other end of the pull-up resistor 3 is connected to a positive terminal of the DC power supply 4, and a negative terminal of the power supply 4 is grounded. Because of this,
The input voltage to the amplifier 6 has the same potential as the power supply 4.

When voice or the like is input to the microphone 2, the diaphragm 2a vibrates, and the capacitance between the microphone 2 and the fixed electrode 2b changes. As a result, a current flows between the drain and the source of the FET 2c, and the input voltage to the amplifier 6 becomes a potential divided by the pull-up resistor 3 and the output impedance of the FET 2c. That is, the input voltage to the amplifier 6 is determined by the output impedance of the FET 2c. Since the output impedance of the FET 2c is determined by the gate voltage, the input voltage to the amplifier 6 changes linearly according to the change in capacitance due to the vibration of the diaphragm 2a.

The output terminal of the amplifier 6 is connected to the DSP 7. That is, the amplified signal output from the amplifier 6 is input to the DSP 7. Specifically, the DSP 7 includes a signal processing unit 7a and a failure diagnosis processing unit 7b, and the amplified signal is input to the signal processing unit 7a and the failure diagnosis processing unit 7b. The signal processing unit 7a and the failure diagnosis processing unit 7b perform predetermined processing based on a predetermined control algorithm set in the DSP 7, respectively.

In the DSP 7, first, a failure diagnosis of the microphone 2 based on the amplified signal is performed in the failure diagnosis processing unit 7b. Specifically, the failure diagnosis processing unit 7b calculates a voltage fluctuation value (a difference between the maximum voltage value and the minimum voltage value) of the amplified signal. Then, when the voltage fluctuation value is lower than a predetermined threshold value preset in the DSP 7, it is determined that the microphone 2 is out of order. When the voltage fluctuation value of the amplified signal is equal to or larger than the threshold value, it is determined that the microphone 2 is normal. Then, the signal processing unit 7a performs signal processing based on the diagnosis result.

Such a failure diagnosis process is performed at predetermined intervals of time. In this embodiment, the failure diagnosis process is performed at the time of starting the engine and at intervals of a predetermined time thereafter. . Further, this failure diagnosis processing is performed immediately after the airbag deployment operation and at every predetermined time thereafter. Further, in the present embodiment, the threshold value is set so as to be substantially equal to the voltage fluctuation value of the lowest possible vehicle noise level. Further, as shown in FIG. 1, output signals (amplified signals) from the plurality of microphones 2 are input to the signal processing unit 7a and the failure diagnosis processing unit 7b. For this reason, the failure diagnosis processing unit 7b performs a failure diagnosis of each microphone 2 based on the amplified signal from each microphone 2. Then, in the signal processing section 7 a, processing such as addition processing is performed using only the amplified signal of the microphone 2 diagnosed as normal, and the processed signal is output to the speech recognition device 8. That is, the microphone device 1 of the present embodiment is embodied as a microphone device 1 including a microphone array including a plurality of microphones 2. When the microphone 2 is out of order, the driver is notified of the malfunction.

Therefore, according to the present embodiment, the following effects can be obtained. (1) The DSP 7 is provided with a failure diagnosis processing unit 7b. When the voltage fluctuation value of the amplified signal from the microphone 2 is lower than a predetermined threshold, the failure diagnosis processing unit 7b 2 is determined to have failed. The threshold value is set to be equal to the voltage fluctuation value due to background noise. Therefore, even if nothing is input to the microphone 2, it is possible to detect whether the microphone 2 is functioning or not. In particular, when the internal circuit of the microphone 2 is disconnected, it is possible to reliably detect the disconnection.

(2) The failure diagnosis processing section 7b diagnoses the failure of the microphone 2 based on the voltage fluctuation value of the amplified signal. That is, the arithmetic processing required by the failure diagnosis processing unit 7b is only the calculation of the voltage fluctuation value of the amplified signal and the comparison of the voltage fluctuation value with the threshold. Therefore, the failure diagnosis processing can be realized by a relatively easy algorithm. In particular, when the failure diagnosis processing unit 7b is configured by a digital circuit, the circuit can be realized with a simple configuration.

(3) The failure diagnosis processing section 7b performs failure diagnosis of the microphone 2 based on the amplified signal from the amplifier 6. For this reason, a minute voltage fluctuation can be detected, and the threshold can be set finely. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the following embodiments, points different from the first embodiment will be mainly described, and common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the microphone device 1 of this embodiment, two resistors 11a and 11b are connected in parallel with the pull-up resistor 3. And these resistors 11a,
Switches 12a and 12b are connected to 11b, respectively. Therefore, the switches 12a and 12b are turned on.
-Pull-up resistor 3 and each resistor 1 according to the OFF state
The combined resistance value of 1a and 11b becomes variable. That is, the pull-up resistor 3, each of the resistors 11a and 11b, and each of the switches 12a and 12b constitute a variable resistor section 13. Each of the switches 12a and 12b is configured by a switching element such as a transistor, and is turned on and off based on a start signal (not shown) from the failure diagnosis processing unit 7b.
N · OFF.

At the time of failure diagnosis of the microphone device 1 configured as described above, the failure diagnosis processing unit 7b first calculates the voltage value of the amplified signal from the amplifier 6 when each of the switches 12a and 12b is turned off. . Also, DSP
7, a voltage value of the amplified signal during normal operation of the microphone 2 is recorded as a reference voltage. The reference voltage is set for each voltage value of the variable resistance value of the variable resistance unit 13.

Then, the failure diagnosis processing section 7b compares the calculated voltage value of the amplified signal with a reference voltage corresponding to the resistance value of the pull-up resistor 3. Thus, when the difference between the two voltage values is equal to or greater than a predetermined threshold value, the failure diagnosis processing unit 7b determines that the microphone 2 has failed.

When the difference between the respective voltage values falls below the threshold value, the failure diagnosis processing section 7b sets the switch 12a to O
In the N state, the voltage value of the amplified signal at the combined resistance value of the pull-up resistor 3 and the resistor 11a is calculated. continue,
The failure diagnosis processing unit 7b calculates the voltage value of the amplified signal when both the switches 12a and 12b are turned on.

Then, the voltage value of the amplified signal at each resistance value is compared with the voltage value of the corresponding reference voltage. Thus, when the difference between the voltage values is equal to or greater than a predetermined threshold value, the failure diagnosis processing unit 7b determines that the microphone 2 corresponding to the amplified signal has failed.

Therefore, according to the present embodiment, the following effects can be obtained. (4) As the microphone 2 changes the resistance value of the variable resistance section 13, the voltage level of the output signal (amplified signal) changes accordingly. Then, even if the voltage level of the output signal between the normal operation and the failure of the microphone 2 is close to the resistance value of the pull-up resistor 3, for example, when the resistance value is changed, the voltage value differs. It will be easier. Therefore, the failure diagnosis of the microphone 2 can be performed with higher accuracy. In particular, it is possible to diagnose a failure not only when a circuit constituting the microphone 2 is disconnected but also when a change in characteristics of the microphone 2 occurs due to a failure of the microphone 2 due to, for example, a partial breakage of the diaphragm 2a. it can. (Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG.

In the microphone device 1 of the present embodiment, the diaphragm 2a of the microphone 2 is grounded via the resistor 14. Further, an AC signal application unit 15 is provided in the failure diagnosis processing unit 7b of the DSP 7. And
The AC signal applying unit 15 is provided between the diaphragm 2a of the microphone 2 and the resistor 14, and between the coupling capacitor 5
An AC reference signal of a predetermined frequency can be provided between the input terminal of the amplifier 6 and the input terminal of the amplifier 6. The frequency of this AC reference signal is specifically set to an audible frequency, for example, 100 Hz, 1 kHz, 10 kHz, etc.
An AC signal of an arbitrary frequency can be given.

At the time of failure diagnosis of the microphone device 1 configured as described above, the failure diagnosis processing unit 7b first applies an AC reference signal between the diaphragm 2a of the microphone 2 and the resistor 14. That is, the ground potential of the microphone 2 is changed by the AC reference signal. Then
The diaphragm 2a is in a state of pseudo-vibration, and the microphone 2 outputs an output signal corresponding to the AC reference signal. That is, the microphone 2 operates in a pseudo manner, and the amplifier 6 outputs an amplified signal corresponding to the AC reference signal.

Then, the failure diagnosis processing section 7b compares the characteristics of the amplified signal with the characteristics of the applied AC reference signal. Specifically, the failure diagnosis processing unit 7b compares the frequency of the amplified signal with the frequency of the AC reference signal. At the same time, the failure diagnosis processing unit 7b compares the voltage fluctuation value (amplitude) of the amplified signal with the voltage fluctuation value (amplitude) of the AC reference signal in consideration of the amplification factor of the amplifier 6. When the voltage fluctuation value of the amplified signal has a difference greater than or equal to a predetermined threshold value set in advance with respect to the voltage fluctuation value of the AC reference signal in consideration of the amplification factor of the amplifier 6, the microphone corresponding to the amplified signal 2
Is determined to have failed. Here, since the AC reference signal is a signal including only a single frequency component, the failure diagnosis processing unit 7b does not need to perform the FFT filter processing or the like. For this reason, the failure diagnosis processing unit 7b can perform the failure diagnosis of the microphone 2 by simply performing the frequency comparison and the voltage fluctuation comparison.

Further, in the present embodiment, the failure diagnosis processing section 7b gives AC reference signals of various frequencies to the microphone 2 and diagnoses the failure of the microphone 2 for each frequency component. ing. For example, the failure diagnosis processing unit 7b first performs a failure diagnosis based on a 100 Hz AC reference signal, and then performs a 500 Hz, 1 kHz
Diagnosis of the failure of the microphone 2 is performed for each frequency component in the audible frequency band, such as z, 5 kHz, 10 kHz,.

Since the microphone 2 is diagnosed using the amplified signal from the amplifier 6, it is determined whether the microphone 2 has failed or the amplifier 6 has failed. It is difficult to do. Therefore, in the present embodiment, when it is determined that the microphone 2 has failed by the failure diagnosis, the failure diagnosis of the amplifier 6 is subsequently performed.

At the time of failure diagnosis of the amplifier 6, the failure diagnosis processing section 7b applies the AC reference signal to the input terminal of the amplifier 6. At this time, the microphone 2 side of the coupling capacitor 5 is cut off by a switching element (not shown) or the like. Then, the characteristic (frequency and voltage fluctuation value) of the amplified signal from the amplifier 6 is compared with the characteristic (frequency and voltage fluctuation value) of the AC reference signal by the failure diagnosis processing unit 7b. Here, the failure diagnosis processing unit 7b
Compares the frequency of the amplified signal with the frequency of the AC reference signal, and determines whether the voltage variation of the amplified signal is a predetermined value with respect to the voltage variation of the AC reference signal in view of the amplification factor of the amplifier 6 during normal operation. When there is a difference equal to or larger than the threshold value, it is determined that the amplifier 6 that outputs the amplified signal is out of order. Therefore, the failure diagnosis of the amplifier 6
Is determined to be normal, it can be determined that the microphone 2 is out of order.

Therefore, according to the present embodiment, the following effects can be obtained. (5) By applying an AC reference signal having a predetermined frequency to the microphone 2, an output signal corresponding to the AC reference signal is output from the microphone 2.
That is, the microphone 2 operates in a pseudo manner. Moreover, if the microphone 2 is normal, the frequency component of the output signal output from the microphone 2 is
It is almost equal to the frequency of the applied AC signal. Therefore, the failure diagnosis processing unit 7b determines whether or not the frequency of the AC signal matches the frequency of the output signal, and compares the voltage fluctuation value of each signal to diagnose the failure of the microphone 2. Can be. Therefore, it is not necessary to use an FFT filter or the like for the failure diagnosis of the microphone 2, and the failure diagnosis of the microphone 2 can be performed simply and reliably.

(6) When the failure diagnosis processing section 7b diagnoses that the microphone 2 has failed by the failure diagnosis for applying the AC reference signal to the microphone 2, the failure diagnosis processing section 7b then supplies the AC reference signal to the input side of the amplifier 6. It is designed to be applied. The failure diagnosis of the amplifier 6 is also performed by comparing the frequency and voltage fluctuation of the amplified signal from the amplifier 6 with the frequency and voltage fluctuation values of the AC reference signal.
Therefore, it can be determined whether the microphone 2 has failed or the amplifier 6 has failed. Moreover, since the AC reference signal has only one frequency component, if the amplifier 6 is normal, the amplified signal also has only that frequency component. Therefore, the failure diagnosis processing unit 7b can easily and reliably perform the failure diagnosis of the amplifier 6. (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG.

In the microphone device 1 of the present embodiment, the trigger switch 16 is connected to the DSP 7. The trigger switch 16 is also connected to the voice recognition device 8, and operates the voice recognition device 8 when the trigger switch 16 is operated. That is, the voice recognition device 8 operates the microphone device 1 only when the trigger switch 16 is operated.
And performs a processing operation based on the processed signal. In the present embodiment, the trigger switch 16 is provided at a location that is easy for the driver to operate, such as a steering column or an instrument panel.

Also in the microphone device 1 configured as described above, the failure diagnosis by the failure diagnosis processing unit 7b is performed based on the amplified signal from the amplifier 6. At the time of the failure diagnosis, the failure diagnosis processing unit 7
b first calculates the voltage value of the amplified signal. Subsequently, the failure diagnosis processing unit 7b outputs the DSP
7, a signal component larger than a predetermined voltage value set in advance is set as a desired signal component (S component), and a signal component smaller than the voltage value is set as a noise component (N component). If the S / N ratio of the amplified signal exceeds a preset first S / N ratio, the failure diagnosis processing unit 7b determines that the microphone 2 has failed. That is, when the ratio of the desired signal component included in the amplified signal is higher than the noise component, the failure diagnosis processing unit 7b determines that the microphone 2 corresponding to the amplified signal has failed. For this reason, the failure diagnosis processing unit 7b determines that the microphone 2 has failed, for example, even when the microphone 2 has moved to a place having a bad noise environment such as in an engine room. That is, the failure diagnosis processing unit 7b determines that the microphone 2 has failed even when a signal component that should be originally recognized as a noise component is erroneously recognized as a desired signal component.

When the microphone 2 is diagnosed to be normal by such a failure diagnosis, the failure diagnosis processing section 7b performs a second failure diagnosis process. During the second failure diagnosis processing, the failure diagnosis processing unit 7b monitors the amplified signal from the amplifier 6 for a predetermined time when the trigger switch 16 is operated, and calculates the S / N ratio of the amplified signal. Then, the failure diagnosis processing unit 7b compares the S / N ratio of the amplified signal with the DSP 7
Is compared with a second S / N ratio set in advance. The failure diagnosis processing unit 7b compares the S / N ratio each time the trigger switch 16 is operated, and the S / N ratio of the amplified signal
State continuously lower than the S / N ratio a plurality of times (for example, 5
Times), it is determined that the microphone 2 corresponding to the amplified signal is out of order. That is, normally, when the trigger switch 16 is operated, sound should be input to the microphone 2. However, nevertheless, if the ratio of the noise components is high, it is considered that the microphone 2 is not functioning properly.

Therefore, according to the present embodiment, the following effects can be obtained. (7) When the S / N ratio of the amplified signal from the amplifier 6 exceeds the first S / N ratio set in advance, the failure diagnosis processing unit 7b fails the microphone 2 corresponding to the amplified signal. Judge that it is. That is, the failure diagnosis processing unit 7
In b, when the ratio of the desired signal component included in the amplified signal is too high, it is determined that the microphone has failed. For this reason, the failure diagnosis processing unit 7b determines that the microphone 2 has failed, for example, even when the microphone 2 has moved to a place having a bad noise environment such as in an engine room. That is, the microphone device 1 of the present embodiment can determine that the microphone 2 has failed even when a signal component that should be originally recognized as a noise component is recognized as a desired signal component.

(8) The failure diagnosis processing section 7b repeats the state where the S / N ratio of the amplified signal from the amplifier 6 when the trigger switch 16 is operated is lower than the second S / N ratio for a predetermined number of times. When the microphone 2 is detected, it is determined that the microphone 2 corresponding to the amplified signal is out of order. That is, the failure diagnosis processing unit 7b performs a failure diagnosis based on an output signal when a positive operation for making the microphone 2 function is performed. Therefore, the failure diagnosis of the microphone 2 can be performed with higher accuracy.

Further, the failure diagnosing means 7b determines that the microphone 2 has failed for the first time when the state where the S / N ratio of the amplified signal is lower than the second S / N ratio is detected continuously for a predetermined number of times. Judge. That is, the failure diagnosis means 7
In b, when the state where the S / N ratio of the amplified signal is lower than the second S / N ratio is detected only once, it is not determined that the microphone 2 is out of order. For this reason, the trigger switch 1
If no sound is input at the time of the operation of 6, the microphone 2 is not erroneously diagnosed as malfunctioning though it is normal.

The embodiment of the present invention may be modified as follows. In the first, second, and fourth embodiments, FIGS.
As shown by a two-dot chain line, a signal on the input side of the amplifier 6, that is, an output signal from the microphone 2 is input to the failure diagnosis processing unit 7b. The failure diagnosis of each of the above embodiments may be performed based on the characteristics of the output signal, and the failure diagnosis of the amplifier 6 may be performed based on the amplified signal from the amplifier 6. Specifically, for example, in the case of the first embodiment, the failure diagnosis of the microphone 2 is performed based on the voltage fluctuation value of the output signal from the microphone 2. When the microphone 2 is operating normally by the failure diagnosis processing unit 7b, the microphone 2 in consideration of the voltage fluctuation value of the amplified signal and the amplification factor of the amplifier 6 is used.
Is compared with the voltage fluctuation value of the output signal from the controller. And
The failure diagnosis processing section 7b causes the amplifier 6 to determine that the amplifier 6 is normal when the difference between the voltage fluctuation values is within the allowable range (a predetermined threshold or less), and the difference between the voltage fluctuation values exceeds the allowable range. Sometimes it is determined that the amplifier 6 is out of order. In this way, it is possible to determine which of the microphone 2 and the amplifier 6 has failed.

In the first, second, and fourth embodiments,
As in the third embodiment, a failure diagnosis of the amplifier 6 may be performed by applying an AC reference signal to the input terminal of the amplifier 6.

In the second embodiment, the failure diagnosis processing unit 7b may perform failure diagnosis by comparing various characteristics such as phase-frequency characteristics and sensitivity-frequency characteristics. Specifically, the failure diagnosis processing unit 7b
An FFT filter (Fast Fourier Transform filter) or the like is provided to calculate the sensitivity for each frequency component, and to calculate each characteristic of the amplified signal for each resistance value of the variable resistor 13. And
The calculated characteristic of each frequency of the amplified signal is compared with a corresponding characteristic of each frequency set in advance, and when the difference exceeds an allowable range (predetermined threshold), it is determined that the microphone 2 has failed. Let it. In this way, the failure diagnosis of the microphone 2 can be performed with higher accuracy.

In the third embodiment, the failure diagnosis processing section 7b performs the failure diagnosis of the microphone 2 by comparing the frequency of the AC reference signal and the amplified signal with the voltage fluctuation. However, the failure diagnosis processing unit 7b compares the phase characteristics of the AC reference signal and the amplified signal in addition to the comparison, and when the phase difference is equal to or larger than the predetermined threshold, the microphone 2 is out of order. It may be determined that it is. In this way, the failure diagnosis of the microphone 2 can be performed with higher accuracy.

In the third embodiment, an AC signal applying unit 15 is provided in the failure diagnosis processing unit 7b, and the AC signal applying unit 15 allows only a single frequency component to be input to the microphone 2 and the input terminal of the amplifier 6. Are applied. However, the AC signal applying unit 1
5 may apply a predetermined reference signal (for example, a harmonic or the like) including a plurality of frequency components to the microphone 2 and the input terminal of the amplifier 6. With this configuration, it is determined whether or not the frequency component included in the amplified signal matches the frequency component included in the reference signal, and
By comparing the voltage fluctuation values for each frequency component, a failure diagnosis of the microphone 2 and the amplifier 6 can be performed. However, in this case, it is necessary to use an FFT filter or the like for failure diagnosis of the microphone 2.

In the fourth embodiment, the trigger switch 16 is connected to the DSP 7, and when the trigger switch 16 is operated, the failure diagnosis processing unit 7b monitors the output signal for a predetermined time thereafter to cause the failure of the microphone 2 to fail. Diagnosis is performed. However, the trigger switch 16
Need not necessarily be connected to the DSP 7. For example, the operation state of the voice recognition device 8 may be monitored by the DSP 7. Then, the failure diagnosis processing unit 7b
May be configured to monitor the output signal for a predetermined time from the start of the operation of the voice recognition device 8 to diagnose the failure of the microphone 2.

In the above embodiments, an electret microphone is used as the microphone 2. However, the present invention is not limited to this.
Various microphones such as a normal condenser microphone and a dynamic microphone may be used.

In each of the above embodiments, the DSP 7 is provided with the failure diagnosis processing unit 7b, and the failure diagnosis processing unit 7b performs the failure diagnosis processing of the microphone 2. However, the failure diagnosis processing is performed by an EC other than the DSP7.
U (for example, airbag ECU) or the like.

In the above embodiments, the signal processing unit 7a
The processing of the failure diagnosis processing unit 7b is performed using the DSP 7. However, the processing of the signal processing unit 7a and the failure diagnosis processing unit 7b is not limited to the DSP 7, and may be performed using a device suitable for signal processing such as a RISC processor or an FPGA.

In each of the above embodiments, the microphone device 1 has a microphone array constituted by a plurality of microphones 2. However, the microphone device 1 may include only one microphone 2.

The external device connected to the microphone device 1 is not limited to the vehicle voice recognition device 8, but may be a device that requires a voice detector, such as a hands-free telephone, a vehicle radio, and a May Day system. Anything is fine.

In each of the above embodiments, the vehicle microphone device 1 is embodied. However, the microphone device 1 may be embodied as a sound detector for applications other than those for vehicles.

[0065]

As described in detail above, according to the first to eighth aspects of the present invention, a failure of a microphone can be detected.

According to the second aspect of the present invention, the failure diagnosis means can be realized with a relatively simple configuration. According to the third aspect of the present invention, the failure diagnosis of the microphone can be performed with higher accuracy.

According to the fourth aspect of the present invention, the failure diagnosis of the microphone can be performed simply and reliably. According to the fifth aspect of the invention, even when a signal component that should be originally recognized as a noise component is recognized as a desired signal component, it can be determined that the microphone has failed.

According to the sixth aspect of the present invention, the failure diagnosis of the microphone can be performed with higher accuracy. According to the seventh aspect of the invention, it is possible to perform failure diagnosis of the amplifying unit.

According to the eighth aspect of the present invention, it is possible to easily diagnose the failure of the amplifying means.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a microphone device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a microphone device according to a second embodiment.

FIG. 3 is a block diagram illustrating a schematic configuration of a microphone device according to a third embodiment.

FIG. 4 is a block diagram illustrating a schematic configuration of a microphone device according to a fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Microphone apparatus, 2 ... Microphone, 3 ... Pull-up resistance, 4 ... DC power supply, 6 ... Amplifier as amplifying means, 7 ... Digital signal processor (DSP),
7a: Signal processing unit; 7b: Failure diagnosis processing unit as failure diagnosis means; 13: Variable resistance unit; 15: AC signal application unit;
16 Trigger switch as output operation means.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsuhide Kumagai 3-260 Toyota, Oguchi-machi, Niwa-gun, Aichi Prefecture F-term in Tokai Rika Electric Works, Ltd.

Claims (8)

[Claims] 1. A microphone comprising: a microphone; and a failure diagnosis means for monitoring an output signal from the microphone and diagnosing whether or not the microphone has failed based on the output signal. apparatus. 2. The method according to claim 1, wherein the failure diagnosis unit determines that the microphone is out of order when a voltage fluctuation value of an output signal from the microphone is lower than a predetermined threshold value. The microphone device according to claim 1. 3. The microphone device includes a power supply for applying a predetermined potential to the microphone and a resistor, and the failure diagnosing means changes a resistance value of the resistor and changes the resistance value with the change. The method according to claim 1, wherein the degree of characteristic fluctuation of the output signal of the microphone is compared with the degree of characteristic fluctuation of the output signal during normal operation of the microphone, and a failure diagnosis of the microphone is performed based on the comparison result. 2. The microphone device according to 1. 4. The failure diagnosis means applies an AC signal of a predetermined frequency to a signal line of the microphone, and determines a characteristic of the output signal of the microphone and a characteristic of the AC signal output as a result. 2. The microphone device according to claim 1, wherein a comparison is made and a failure diagnosis of the microphone is performed based on the comparison result. 5. The failure diagnosis unit sets a signal component of a predetermined voltage value or more in an output signal from the microphone as a desired signal component, and sets a signal component less than the predetermined voltage value as a noise component. The microphone device according to claim 1, wherein when the S / N ratio based thereon exceeds a predetermined S / N ratio set in advance, it is determined that the microphone is out of order. 6. The failure diagnosis means monitors an output signal from the microphone for a predetermined time when an operation means for operating an external device to which a processing signal processed by the microphone device is input is operated. And determining that the microphone is out of order when continuously detecting a state in which the S / N ratio of the output signal is lower than a predetermined S / N ratio for a predetermined number of times. The microphone device according to claim 1 or 5, wherein 7. The microphone device includes amplification means for amplifying an output signal from the microphone, and the failure diagnosis means monitors a characteristic of the output signal on an input side of the amplification means, and based on the characteristic. Performing a failure diagnosis of the microphone by monitoring the characteristics of the amplified signal output from the amplifying means, and determining the amplification factor for each frequency component of the amplified signal with respect to the output signal on the input side of the amplifying means. 2. The apparatus according to claim 1, wherein when the amplification factor is different from the amplification factor for each frequency component during normal operation of the means, the amplification means is determined to be faulty.
The microphone device according to claim 6. 8. The microphone device includes amplification means for amplifying an output signal from the microphone, wherein the failure diagnosis means applies an AC signal of a predetermined frequency to an input side of the amplification means, and 2. The apparatus according to claim 1, wherein the amplified signal output from the means is monitored, the characteristic of the amplified signal is compared with the characteristic of the AC signal, and a failure diagnosis of the amplifier is performed based on the comparison result. The microphone device according to claim 6.