JP6136628B2 - Apparatus and method for inspecting sound output of device under test - Google Patents

Description

  The present invention relates to a sound output inspection apparatus and method for a device under test.

  In the manufacturing process of a workpiece with a speaker such as a computer or a mobile phone, the frequency characteristics, noise, and sound are output by actually outputting sound from the speaker, collecting the sound with a microphone of the inspection device, and performing spectrum analysis. The operation of the speaker is checked by measuring cracks and the like.

JP 2006-279758 A

  In recent years, it has been required to test a speaker in a short time for the purpose of improving production efficiency. However, in the speaker testing method based on spectrum analysis, since the sample length and the inspection accuracy are in a trade-off relationship, the inspection time has to be set long in order to guarantee the inspection accuracy.

  Here, if the cross-correlation between the signal collected by the microphone and the signal that is supposed to be output from the speaker is calculated, the speaker can be tested in a short time. However, if the speaker is inspected while the work is being transported by the transport device in order to improve production efficiency, the sound source speaker will be tested while being moved by the transport device, so the sound collected by the microphone is the frequency due to the Doppler shift. It fluctuated and correct audio data could not be collected. In particular, when the transport speed of the transport device is increased, the Doppler shift is increased, which makes it difficult to accurately inspect the workpiece. In order to correct the Doppler shift, sensors for measuring the position and moving speed of the workpiece are required, but these sensors cause a complicated configuration of the inspection apparatus.

For this reason, it has been desired to accurately evaluate the workpiece without measuring the workpiece position and speed even when the voice from the workpiece is Doppler shifted.
Accordingly, as one aspect, an object of the present invention is to enable accurate evaluation of a workpiece without measuring the position and speed of the workpiece even when the sound from the workpiece is Doppler shifted.

  According to one aspect of the embodiment, a microphone that collects audio output from a speaker based on a waveform signal of a moving test subject and acquires a first waveform signal, and the first that is collected by the microphone 1 waveform signal is compared with a second waveform signal including the same waveform as the waveform signal of the DUT, and a Doppler shift amount of the first waveform signal with respect to the second waveform signal is calculated. A Doppler ratio extractor; a waveform restorer that corrects frequency fluctuations of the first waveform signal using the Doppler shift amount; the first waveform signal and the second waveform signal restored by the waveform restorer; A cross-correlation calculator that calculates a cross-correlation value of the test object, and a pass / fail determination unit that determines that the speaker of the DUT is normal when the cross-correlation value is equal to or greater than a predetermined threshold. Audio output test apparatus of the test body is provided to move, characterized in that.

  Further, according to another aspect of the embodiment, the step of collecting the sound output from the speaker based on the waveform signal of the moving test subject and acquiring the first waveform signal; A Doppler shift amount between the waveform signal and a second waveform signal including the same waveform as the waveform signal of the DUT is calculated, and the Doppler shift of the first waveform signal is corrected from the Doppler shift amount. A step of calculating a cross-correlation value between the corrected first waveform signal and the corrected second waveform signal, and the DUT when the cross-correlation value is equal to or greater than a predetermined threshold value. And a step of determining that the speaker is normal. A method for inspecting a moving object under test is provided.

  Without providing a sensor for measuring the position and moving speed of the device under test, the relationship between the sample length and the test accuracy can be improved, and the device under test can be tested by cross-correlation calculation.

FIG. 1 is a block diagram showing an example of a schematic configuration of an audio output inspection apparatus and a device under test according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the configuration of the calculation unit of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 3 is a flowchart for explaining an example of processing of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a signal waveform processed by the audio output inspection apparatus according to the embodiment of the present invention. FIG. 5 is a diagram for explaining an example of processing of the arithmetic unit of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a configuration of a Doppler ratio extractor and a waveform restorer of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a waveform signal input to the Doppler ratio extractor of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 8 is a diagram illustrating an example of the output of the Doppler ratio extractor of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 9 is a diagram showing an example of input and output of the waveform decompressor of the audio output inspection apparatus according to the embodiment of the present invention. FIG. 10 is a diagram schematically illustrating an example of the cross-correlation calculation process of the audio output inspection apparatus according to the embodiment of the present invention.

The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
The foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the invention.

Initially, the structure of the to-be-tested object used as the test object of the audio | voice output test | inspection apparatus 1 of embodiment is demonstrated.
A device under test 2 that is a workpiece is transported in a method indicated by an arrow by a transport device 3 such as a belt conveyor. The device under test 2 includes a speaker 11 that outputs sound, a speaker control device 12 that controls the speaker 11, a CPU (Central Processing Unit) 13 that performs various data processing, and a data storage device 14. Has been. Examples of such a device under test 2 include a computer such as a notebook computer. In this case, a display device (not shown), an output device, a data input device, a communication control device, and the like are added to the device under test 2 as necessary. Further, the device under test 2 may be a device other than a computer.

Further, the storage device 14 stores a first inspection sound source 15. The first inspection sound source 15 has information for outputting sound from the speaker 11 at the time of the test, and is stored in the storage device 14 in a known file format, for example.
The CPU 13 is configured to read out the first inspection sound source 15 and output data of the first inspection sound source 15 to the speaker control device 12.
The speaker control device 12 is configured to control current supply to the speaker 11 so that sound based on the first inspection sound source 15 can be output from the speaker 11.

Next, the configuration of the audio output inspection apparatus 1 that inspects the device under test 2 will be described.
The sound output inspection device 1 converts the sound output from the speaker 11 of the device under test 2, the sampler 22 that performs A / D (Analog / Digital) conversion of the sound of the microphone 21, and the sampler 22. And a storage device 23 for storing a waveform signal of audio data. Further, the audio output inspection device 1 includes a calculation unit 24 that determines data processing and pass / fail of the device under test 2, and a storage device 25. The storage device 25 stores a second inspection sound source 26 (second waveform signal) used for data processing. The second inspection sound source 26 includes the same waveform signal as that of the first inspection sound source 15.

Next, the calculation unit 24 will be described with reference to the functional block diagram of FIG.
The cue signal detector 31 detects a cue signal included in the waveform signal of the audio data acquired from the DUT 2. The waveform signal from which the cue signal has been removed by the cue signal detector 31 is output to the storage device 32. The storage device 32 can temporarily store the waveform signal, and its output is connected to the first sync tone extractor 33 and the first sync tone remover 34. The first sync tone extractor 33 extracts a sync tone from the waveform signal. The first sync tone remover 34 removes the sync tone from the waveform signal.

  On the other hand, the second inspection sound source 26 is connected to a second synchronization tone extractor 35 and a second synchronization tone remover 36. The second synchronization tone extractor 35 extracts a synchronization tone from the second inspection sound source 26. The second sync tone remover 36 removes the sync tone from the second inspection sound source 26.

The outputs of the first sync tone extractor 33 and the second sync tone extractor 35 are connected to a Doppler ratio extractor 37. The Doppler ratio extractor 37 calculates a Doppler shift amount by a process described later. The Doppler shift amount is output to the waveform restoring unit 38.
The waveform restoring unit 38 receives the waveform signal from the first synchronous tone remover 34 in addition to the Doppler shift amount, and restores the waveform signal in which the Doppler effect is canceled. The output of the waveform restoring unit 38 is connected to a cross correlation calculator 39.
The output of the second synchronous tone remover 36 is also connected to the cross correlation calculator 39. The cross-correlation calculator 39 calculates the cross-correlation between the waveform of the waveform signal restored by the waveform restorer 38 and the waveform of the second inspection sound source 26 from which the sync tone has been removed. The output of the cross-correlation calculator 39 is connected to the pass / fail determination unit 40.
The pass / fail determination unit 40 is configured to determine pass / fail of the device under test 2 based on the calculation result of the cross-correlation calculator 39 and output the result.

Next, processing of the audio output inspection apparatus 1 will be described with reference to the flowchart of FIG.
In step S <b> 101, the inspection sound stored in the storage device 14 of the device under test 2 is output from the speaker 11. In subsequent step S102, the sound output inspection apparatus 1 collects the sound output from the speaker 11 of the device under test 2 using the microphone 21, and A / D converts the analog signal of the sound collected by the sampler 22. Further, the digital waveform signal after A / D conversion is stored in the storage device 23.

  In step S <b> 103, first, a waveform signal is input to the calculation unit 24. In the calculation unit 24, the cue signal detector 31 detects a cue signal provided at the front end portion of the waveform signal, removes the cue signal, and extracts the waveform signal of only the portion necessary for the examination. The extracted waveform signal (hereinafter referred to as the first test signal) is stored in the storage device 32. In subsequent step S104, the first synchronization tone extractor 33 extracts the synchronization tone (received synchronization tone) included in the first test signal. On the other hand, in step S105, the first sync tone remover 34 removes the received sync tone from the first test signal.

  On the other hand, in step S <b> 106, the calculation unit 24 reads a waveform signal (hereinafter referred to as a reference test signal) of the second inspection sound source 26 stored in the storage device 25. Subsequently, in step S107, the second synchronization tone extractor 35 extracts a synchronization tone (reference synchronization tone) included in the reference test signal. On the other hand, in step S108, the second sync tone remover 36 removes the reference side sync tone from the reference test signal.

  Further, in step S109, the reception synchronization tone and the reference synchronization tone are input to the Doppler ratio extractor 37, and the frequency fluctuation amount of the reception synchronization tone with respect to the reference synchronization tone of the inspection sound source 26 of the audio output inspection apparatus 1, that is, the Doppler shift amount is calculated. Extract. In step S110, the Doppler shift amount is used, the reception test signal from which the reception synchronization tone is removed in step S105 is corrected, and the modulation by frequency modulation is corrected.

  Thereafter, in step S111, the cross-correlation calculation unit 39 performs cross-correlation calculation using the corrected reception test signal and the reference test signal based on the second inspection sound source 26 possessed by the audio output inspection apparatus 1. Subsequently, in step S112, the pass / fail determination unit 40 determines pass / fail of the device under test 2 based on the calculation result of the cross correlation. Specifically, the calculation result of the cross correlation is compared with a predetermined pass / fail slice level. For example, if the sound output from the speaker 11 of the device under test 2 is abnormal, the degree of coincidence between the corrected reception test signal and the reference test signal is low, so that the value of the calculation result of the cross-correlation becomes small, and pass / fail Below slice level. In this case, the pass / fail determination unit 40 determines that the DUT 2 is a defective product. On the other hand, if the sound output from the speaker 11 of the device under test 2 is as designed, the degree of coincidence between the corrected reception test signal and the reference test signal is high, and the value of the calculation result of the cross correlation is large. It becomes more than pass / fail slice level. In this case, the pass / fail determination unit 40 determines that the DUT 2 is a non-defective product.

Here, a specific example of the waveform signal will be described.
FIG. 4 shows an example of the signal waveform of the first inspection sound source 15. FIG. 4A shows the entire signal waveform of the waveform signal and each signal extracted from the waveform signal. FIG. 4B is an enlarged view showing the area AR1 of the signal waveform of FIG. The waveform signal S corresponds to the waveform signal stored in the first inspection sound source 15. The signal waveform S first has a cue signal S2, followed by a signal obtained by superimposing a reference synchronization tone signal S4 on a reference test signal S3 which is a chirp for inspection. The frequency of the cue signal S2 is, for example, 1 kHz. The frequency of the reference test signal S3 is, for example, 100 Hz to 10 kHz. The reference synchronization tone signal S4 is 24 kHz.

During the test, sound corresponding to the waveform signal S is output from the speaker 11, but sound whose frequency is modulated by the Doppler effect is collected in the microphone 21 of the sound output inspection apparatus 1. That is, data obtained by frequency-modulating the waveform signal S is input to the storage device 23 of the audio output inspection apparatus 1.
Further, the remaining reference test signal S3 + reference synchronization tone signal S4 obtained by removing the cue signal S2 from the waveform signal S is used as the second test sound source 26 (second waveform signal) of the voice output test apparatus 1 as the reference test signal. ). Note that the second inspection sound source may have a cueing signal shown in FIG.

Next, a specific example of data processing using a waveform signal as shown in FIG. 4 will be described.
Inspecting the device under test 2 includes, for example, a conveyance speed of the conveyance device 3 of 2 m / second, a height from the speaker 11 to the microphone 21 of 0.3 m, and an offset amount between the speaker 11 and the microphone 21 in a direction orthogonal to the conveyance direction. Is executed under the condition of 0.2 m. The sound corresponding to the waveform signal S shown in FIG. 4 is output from the speaker 11 while moving the device under test 2 in this way. Since the device under test 2 is moving, the signal detected by the microphone 21 of the audio output inspection apparatus 1 is not the waveform signal S shown in FIG. 4 but a waveform signal formed by the frequency fluctuation of the waveform signal S. It becomes SW.

  The waveform signal SW is input to the storage device 23 after A / D conversion by the sampler 22. Further, the waveform signal SW is input from the storage device 23 to the cue signal detector 31. The cue signal detection unit 31 extracts the first waveform signal S3W + S4W from which the cue signal S2 has been removed. The first waveform signal S3W + S4W is obtained by changing the frequency of the waveform signal S3 + S4 shown in FIG. 4A due to the Doppler effect. The first waveform signal S3W + S4W is temporarily stored in the storage device 32, and the reception synchronization tone signal S4W is extracted by the first synchronization tone extractor 33, and the reception test signal S3W by the first synchronization tone remover 34. Is extracted. Both the reception test signal S3W and the reception synchronization tone signal S4W are obtained by changing the frequency of the reference test signal S3 and the reference synchronization tone signal S4 shown in FIG. 4A due to the Doppler effect.

  On the other hand, the original signal S3 + S4 is obtained from the second inspection sound source 26 of the storage device 25 of the audio output inspection apparatus 1. From this signal S3 + S4, the second sync tone extractor 35 extracts the reference sync tone signal S4, and the first sync tone remover 36 extracts the reference test signal S3.

Subsequently, the Doppler ratio extractor 37 calculates the Doppler shift amount from the reference synchronization tone signal S4 that does not fluctuate in frequency and the reception synchronization tone signal S4W output from the DUT 2. Further, the waveform restoring unit 38 inversely modulates the reception test signal S3W outputted from the device under test 2 by the Doppler shift amount, and restores the waveform signal Sd outputted from the device under test 2.
Then, the cross-correlation calculator 39 checks the correlation between the restored waveform signal Sd and the original reference test signal S3 that is not frequency-modulated, and evaluates the device under test 2.

A specific example of the circuit configuration and processing of the Doppler ratio extractor 37 and the waveform restorer 38 will be described with reference to FIG.
The Doppler ratio extractor 37 includes a first logic circuit 51 to which the synchronization tone signal S4W is input and a second logic circuit 52. The reference synchronization tone S4 is input to the first logic circuit 51 through the π / 4 phase shifter 53 and also input to the second logic circuit 52. The output of the first logic circuit 51 is input to the logic circuit 57 through the low pass filter 55. On the other hand, the output of the second logic circuit 52 is input to the logic circuit 57 through the low-pass filter 56. Then, the logic circuit 57 calculates the Doppler shift amount by subtracting the output of the second logic circuit 52 from the output of the first logic circuit 51.

  For example, as shown in FIG. 7 with a part of an example of the signal waveform overlapped, the reception synchronization tone S4W is shifted from the reference synchronization tone S4. In the example of FIG. 7, the incoming sync tone S4W is moving more than the reference sync tone S4. Then, by performing calculations using these two synchronization tones S4 and S4W, a Doppler shift amount as shown in FIG. 8 is calculated. In FIG. 8, the horizontal axis indicates time, and the vertical axis indicates the phase difference detection result, that is, the Doppler shift amount.

  Further, as shown in FIG. 6, when the Doppler shift amount is input to the waveform restoring unit 38, the sign determining unit 61 determines the sign, and then the first logic circuit 62 and the second logic circuit 63 are used. Entered. The reception test signal S3W is input to the first logic circuit 62 via the π / 4 phase shifter 64. On the other hand, the reception test signal S3W is input to the second logic circuit 62 as it is. The output of the first logic circuit 62 is input to the logic circuit 67 through the low pass filter 65. On the other hand, the output of the second logic circuit 63 is input to the logic circuit 67 through the low-pass filter 66. Then, the logic circuit 67 subtracts the output of the second logic circuit 63 from the output of the first logic circuit 62, thereby correcting the frequency of the reception test signal S3W and obtaining the reception test signal Sd. The circuit configurations and signal processing algorithms of the Doppler ratio extractor 37 and the waveform restoration unit 38 are not limited to the example shown in FIG. In addition, the waveform restorer 38 may correct the frequency variation of the first waveform signal (S3W + S4W) on which the synchronization tone S4W is superimposed.

  Here, an example of the reception test signals S3W and Sd before and after the frequency correction is shown in FIG. By correcting the frequency using the Doppler shift amount, the phase of the reception test signal S3W is corrected, and the reception test signal Sd actually output from the speaker 11 of the device under test 2 is obtained. The reception test signal Sd is obtained by invalidating the influence of the Doppler shift of the waveform signal accompanying the movement of the device under test 2 and is collected by the microphone 21 when the test is performed without the device under test 2 moving. This corresponds to a waveform signal.

Next, an example of the cross-correlation calculation shown in step S111 of FIG. 3 will be described. The cross-correlation calculation is obtained by the cross-correlation calculator 39 taking the product of the instantaneous values of the two waveforms and calculating the sum. . The cross-correlation is calculated by the following formula, for example.

Here, _xn indicates waveform data of the reference test signal. y _n denotes the data of the received test signal Sd removing the Doppler shift. N indicates the length of the data string. m represents an assumed initial phase shift amount. For example, in the example of FIG. 10, the product x ₁ × y ₁ of the instantaneous value x 1 of the reference test signal S3 at time ₁ and the instantaneous value y ₁ of the reception test signal S3d at the same time is calculated. Similarly, at time 2, the product x ₂ × y ₂ is calculated. A cross-correlation value is obtained by calculating the sum of these products. Then, as described above, the pass / fail determination unit 40 compares the cross-correlation value with the pass / fail slice level to determine pass / fail of the device under test 2.

  As described above, in this embodiment, the first waveform signal collected from the moving test object 2 is corrected with the second waveform signal, so that the Doppler shift caused by the movement of the test object 2 is performed. Was corrected. This makes it possible to detect the Doppler shift amount of the first waveform signal and correct the Doppler shift without providing a sensor for measuring the position and moving speed of the DUT 2. As a result, the test of the device under test 2 by cross-correlation calculation becomes possible, the relationship between the sample length and the test accuracy is improved, and the sound output test can be performed while moving the device under test 2.

  All examples and conditional expressions given here are intended to help the reader understand the inventions and concepts that have contributed to the promotion of technology, and such examples and It is to be construed without being limited to the conditions, and the organization of such examples in the specification is not related to showing the superiority or inferiority of the invention. While embodiments of the present invention have been described in detail, various changes, substitutions and variations can be made thereto without departing from the spirit and scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Audio | voice output test apparatus 2 Test object 11 Speaker 21 Microphone 15 1st test | inspection sound source 25 Memory | storage device 26 2nd test | inspection sound source 37 Doppler ratio extractor 38 Waveform decompressor 39 Cross correlation calculator 40 Pass / fail judgment part S3 + S4 2nd Waveform signal S3W + S4W First waveform signal S4 Reference synchronization tone S4W Reception synchronization tone

Claims (5)

A microphone that collects the sound output from the speaker based on the waveform signal of the moving device under test and acquires the first waveform signal;
The first waveform signal collected by the microphone is compared with a second waveform signal including the same waveform as the waveform signal of the device under test, and the first waveform signal with respect to the second waveform signal is compared. A Doppler ratio extractor for calculating the amount of Doppler shift of
A waveform restorer that corrects frequency fluctuations of the first waveform signal using the Doppler shift amount;
A cross-correlation calculator for calculating a cross-correlation value between the first waveform signal and the second waveform signal restored by the waveform restorer;
When the cross-correlation value is equal to or greater than a predetermined threshold, a pass / fail determination unit that determines that the speaker of the device under test is normal;
A sound output inspection device for a moving subject to be tested, comprising: The first waveform signal and the second waveform signal include a synchronization tone for synchronizing the waveform signal,
2. The Doppler ratio extractor is configured to calculate a Doppler shift amount from a phase shift amount of a synchronous tone included in each of the first waveform signal and the second waveform signal. 2. An apparatus for inspecting a moving object under test as described in 1.   The voice output inspection apparatus for a moving object under test according to claim 1 or 2, further comprising a storage device (25) for storing the second waveform signal. Collecting the sound output from the speaker based on the waveform signal of the moving device under test, and acquiring the first waveform signal;
Calculating a Doppler shift amount between the first waveform signal and a second waveform signal including the same waveform as the waveform signal of the DUT;
Correcting the Doppler shift of the first waveform signal from the Doppler shift amount;
Calculating a cross-correlation value between the corrected first waveform signal and the second waveform signal;
A step of determining that the speaker of the device under test is normal when the cross-correlation value is equal to or greater than a predetermined threshold;
A method for inspecting a moving object under test, comprising: The first waveform signal and the second waveform signal include a synchronization tone for synchronizing the waveform signal,
5. The voice output of the moving test object according to claim 4, wherein a Doppler shift amount is calculated from a phase shift amount of a synchronous tone included in each of the first waveform signal and the second waveform signal. Inspection method.

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