JP3277440B2 - Acoustic characteristics measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic characteristic measuring apparatus for measuring a transfer function of an object from an audio signal supplied to the object and an audio signal output from the object to obtain an acoustic characteristic. .

[0002]

2. Description of the Related Art Conventionally, in an acoustic characteristic measuring apparatus for measuring acoustic characteristics by using a plurality of measuring microphones and microphone amplifiers, an input signal supplied to a sound reproducing apparatus including a power amplifier and a speaker and each microphone. The output signal from the amplifier is subjected to fast Fourier transform (FFT) processing to obtain the power spectrum and the cross spectrum of the input signal and the output signal, and the average value of the cross spectrum is divided by the average value of the power spectrum of the input signal. ,
The acoustic characteristics of the microphone position are measured.

[0005] More specifically, a description will be given with reference to a flowchart of a procedure for measuring acoustic characteristics shown in FIG.

FIG. 6 shows signals used in an acoustic characteristic measuring apparatus. For example, an input signal x (t), which is audio data, is supplied to a device under test 1 and an input IN
It is output to the input terminal 2 as a signal of ₁ . Also, output from the DUT 1, the output signal y corresponding to the input signal x (t) (t) is outputted to the input terminal 3 as a signal input IN _2. In the acoustic characteristic measuring device, the transfer function of the device under test is measured using the input signal x (t) and the output signal y (t) output to the input terminals 2 and 3 to determine the acoustic characteristic.

[0005] First, in step S1 of FIG.
The voice data of N ₁ and IN ₂ is fetched, and step S2
In, considering a case where audio data input IN ₂ against the input IN ₁ audio data is delayed beyond the point number in the range of the fast Fourier transform, as it is from the top as the audio data of the input IN ₂ extraction, as the audio data of the input iN ₁ fetches delays from the start of the audio data of the correction amount.

[0006] Next, the FFT processing after it has been multiplied by a time window based on the waveform of the input IN ₁ at step S3, also the FFT processing after it has been multiplied by a time window based on the waveform of the input IN ₂ in step S4 By doing so, the inputs IN ₁ , IN ₂
Is obtained.

[0007] Thus, to calculate the power spectrum for each frequency point of the input IN ₁ in step S5, it calculates a power spectrum for each frequency point of the input IN ₂ in step S6. Further, in step S7, the input IN
Calculating the cross spectrum with the power spectrum of _1, IN _2.

Thereafter, in step S8, the above-mentioned step S
It is determined whether or not the processing operation from 3 to S7 has been performed N times for averaging for each frequency point. If the processing operation has not been performed N times, the process returns to step S3, and the processing operation from steps S3 to S7 is performed. If N times, step S
9 and input IN ₁ and IN _{2 for} each frequency point.
The average value of the power spectrum and the average value of the cross spectrum are obtained.

Further, in step S10, the inputs IN ₁ ,
Using the average value and the average value of the cross-spectrum of the power spectrum of the IN _2, to calculate the interference-called coherence is the nature of the interfering wave mutually, calculates the transfer function in step S11.

Thereafter, in step S12, a reliability discriminating process for discriminating whether or not the coherence value is equal to or more than a certain value is performed for each frequency point, and only the transfer function having the coherence value equal to or more than a certain value is determined. The measurement result is used.

Further, in step S13, it is determined whether or not so-called averaging of the transfer function for each frequency point is set. If the averaging has not been set, the measurement process of the acoustic characteristics ends.
However, if averaging is set, the transfer function at that frequency point is displayed as acoustic characteristics.

In step S14, it is determined whether all the measurements have been completed. Thus, if it is determined that all the measurement operations have been completed, the measurement process of the acoustic characteristics is completed. If it is determined that all the measurements have not been completed, the process returns to step S1, and the input IN
Captures _1, IN ₂ signals, step S2~S13
The measurement processing of the acoustic characteristics up to is repeated.

[0013]

In a conventional acoustic characteristic measuring apparatus, a plurality of measuring microphones are used.
The acoustic characteristics are measured at the positions of these measurement microphones, and the transfer function of each measurement microphone is measured as a separate acoustic characteristic. In other words, the above-described acoustic characteristic measuring device only measures the acoustic characteristics of each measurement microphone, and consequently obtains a plurality of different acoustic characteristics.

However, when there is only one system of sound reproducing device for a plurality of measurement microphones, one system of equalizer is operated based on a plurality of acoustic characteristics, that is, measurement results.
Adjusting the acoustic characteristics is not easy.

[0015] In view of the above circumstances, the present invention provides an acoustic characteristic measuring apparatus capable of easily adjusting the reproduction of a sound using the acoustic characteristics of a plurality of measurement microphones.

[0016]

An acoustic characteristic measuring apparatus according to the present invention comprises: an orthogonal transform means for performing an orthogonal transform process on an input signal and an output signal; and each spectrum of the input signal and the output signal from the orthogonal transform means. Spectrum calculating means for calculating the power spectra of the input signal and the output signal using the power spectra of the input signal and the output signal, and calculating an average value of the power spectra of the input signal and the output signal using the power spectra of the input signal and the output signal; Transfer characteristic calculating means for calculating the transfer characteristic of each frequency component using the average value of the power spectrum of the input signal and the output signal from the calculating means,
The above-mentioned object is achieved by providing an acoustic characteristic calculating means for obtaining an acoustic characteristic by averaging the average value of the transfer characteristics for each of the plurality of measurement microphones from the transfer characteristic calculating means.

Here, coherence calculating means for calculating a coherence value using the average value of the power spectrum and the average value of the cross spectrum of the input signal and the output signal, and each frequency component from the transfer characteristic calculating means. Averaging means for averaging only the transfer characteristic of the component of the frequency at which the value of the coherence from the coherence calculating means is equal to or greater than a predetermined value, wherein the acoustic characteristic calculating means comprises: The average value of the transfer characteristics for each of the plurality of measurement microphones from the conversion means is averaged to obtain acoustic characteristics.

Further, the acoustic characteristic measuring device according to the present invention comprises:
Orthogonal transform means for performing orthogonal transform processing on the input signal and the output signal, and calculating each power spectrum of the input signal and the output signal using each spectrum of the input signal and the output signal from the orthogonal transform means, And a spectrum calculating means for calculating an average value of the power spectrum of the input signal and the output signal using each power spectrum of the output signal, and an average value of the power spectrum of the input signal and the output signal from the spectrum calculating means. A transfer characteristic calculating means for calculating a transfer characteristic of a frequency component, and an average value of a transfer characteristic of at least one measurement microphone is independently obtained from an average value of the transfer characteristics for each of the plurality of measurement microphones from the transfer characteristic calculation means. And an acoustic characteristic calculating means for extracting the acoustic characteristics.

[0019]

According to the present invention, an input signal and an output signal obtained by converting the input signal into an acoustic signal and picked up by a plurality of measurement microphones are used to calculate a frequency component from the spectrum of the input signal and the output signal. Calculate the transfer characteristics for each
By averaging only the transfer characteristics of frequency components above a certain value, 1
By obtaining the average value of the transfer characteristics of each frequency component of one measurement microphone, and further averaging the average value of the transfer characteristics of each frequency component of the multiple measurement microphones to obtain the acoustic characteristics,
Variations in acoustic characteristics due to the position of the measurement microphone can be suppressed.

Further, a coherence value is calculated using the average value of the power spectrum of the input signal and the output signal and the average value of the cross spectrum, and only the transfer characteristic of the frequency component whose coherence value is equal to or more than a certain value is averaged. Thus, the reliability of the transfer function to be obtained can be improved.

Further, by independently taking out the average value of the transfer characteristics of at least one measurement microphone from the average value of the transfer characteristics of a plurality of measurement microphones, it is possible to obtain a measurement result of an arbitrary measurement microphone as an acoustic characteristic. Can be.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a system using the acoustic characteristic measuring device according to the present invention.

The audio data from the input terminal 41 of the system shown in FIG. 1 is input to the equalizer 42 and also to the acoustic characteristic measuring device 45.

The audio data adjusted by the equalizer 42 is output from a speaker 44 via a power amplifier 43.

This system is equipped with five measuring microphones. These measurement microphones MC _{1 to} MC ₅
Is connected to a microphone amplifier 47 _{1-47 5} each further microphone amplifier 47 _{1-47 5} are connected to the terminals b~f in the signal switching unit 46. When any one of the terminals b to f in the signal switch 46 is switched and connected, the measurement microphones MC _{1 to} MC _{5 are connected.}
Is amplified by the corresponding microphone amplifier and input to the acoustic characteristic measuring device 45 via the signal switch 46.

Thus, the transfer function is calculated using the two-channel analog audio signal of the audio data from the input terminal 41 and any one of the audio data from the measurement microphones MC _{1 to} MC ₅ , and the amplitude and phase are calculated. Are obtained, and these transfer characteristics are added for each frequency component to perform averaging, that is, averaging. Further, by averaging the transfer characteristics of each of the measurement microphones MC _{1 to} MC _5, one acoustic characteristic is obtained, and the power amplifier 43
And a signal output from a single system of sound reproducing device including the speaker 44.

When the signal switch 46 is switched to the terminal a, the acoustic characteristics between the audio data from the input terminal 41 and the audio data adjusted by the equalizer 42 can also be measured.

Next, FIG. 2 shows a schematic configuration of the acoustic characteristic measuring device, and the measurement of the acoustic characteristic will be described below.

Here, the number of samples of the audio signal required for the measurement of the transfer function is determined by the fast Fourier transform (FFT) described later.
, And the number of times of averaging the power spectrum and the cross spectrum described later. For example, when the number of samples required for the measurement of the transfer function is S, the number of points of the fast Fourier transform is P, and the number of times of averaging is N, the number of samples S required for the measurement of the transfer function is S
Is represented by the following equation (1).

S = P × N (1) Specifically, the point number P of the fast Fourier transform is 204
8, when the average number N is 10, the number of samples S
Is the value of 2048 × 10 = 20480.

[0031] For example, the signal input IN ₁ input to the input terminal 11 of FIG. 2 is connected to one microphone that is switched and selected by the signal switching device 46 within the microphone MC ₁ to MC ₅ in FIG. 1 The input signal from the microphone amplifier 47 is a digitally converted signal, and the input IN ₂ signal input to the input terminal 21 in FIG. 2 is a signal obtained by digitally converting the signal output to the power amplifier 43 in FIG. And

Here, the signal of the input IN _{1 corresponds} to the input I
In consideration of the case where the signal of N ₂ is delayed beyond the range of the number of points of the fast Fourier transform, the signal of input IN ₂ is taken out from the head of the signal data as it is and the input I 2
The N ₁ signal taken out is delayed from the beginning of the signal data correction component.

The signal at the input IN ₁ is output from the input terminal 11 to the multiplier 13, and the signal at the input IN ₂ corresponding to the signal at the input IN ₁ is output from the input terminal 21 to the multiplier 23.

Here, when a speech waveform of a predetermined number of samples is cut out, abrupt changes do not occur at both ends of the cut-out section, and in the spectral domain, the convolution of the Fourier transform of the window function is applied to the signal spectrum. That is, in order to perform weighted moving average, a process of multiplying the original waveform by a time window is required. Therefore, the window function generators 12, 2
From 2, a window function corresponding to the band of the signal sent to the multipliers 13 and 23 is generated and supplied to the multipliers 13 and 23. Thus, the multipliers 13 and 23 multiply the band signal by the window function, and the multiplied signals are sent to the FFT analyzers 14 and 24, respectively.

The FFT analyzers 14 and 24 perform a fast Fourier transform process on the transmitted signal data to obtain the frequency spectrum of the signal at the input IN ₁ and the input IN _1.
The frequency spectrum of the _two signals is determined.

When the complex data of the spectrum of the input IN ₁ is X (k), the complex data X (k) is sent to the multiplier 16 and also to the complex conjugate converter 15. The complex conjugate converter 15 converts the sent complex data X (k) into complex conjugate data X ^* (k) and sends it to the multiplier 16. The multiplier 16 multiplies the complex data X (k) from the FFT analyzer 14 by the complex conjugate data X ^* (k) to obtain a power spectrum X ^* (k) X (k) of the input IN _1. Can be This power spectrum X ^* (k) X (k) is stored in the register 31a.

Similarly, assuming that the complex data of the spectrum of the input IN ₂ is Y (k), this complex data Y
(K) is sent to the multiplier 26 and also to the complex conjugate converter 25. The complex conjugate converter 25 converts the sent complex data Y (k) into complex conjugate data Y ^* (k), and sends the complex conjugate data Y ^* (k) to a multiplier 26. In the multiplier 26, the complex data Y (k) from the FFT analyzer 24 and the complex conjugate data Y ^* (
k) and is multiplied by the power spectrum of the input IN ₂ Y ^*
(k) Y (k) is determined. This power spectrum Y
^* (k) Y (k) is stored in the register 31c.

Further, the complex conjugate data X ^* () of the spectrum of the input IN ₁ output from the complex conjugate converter 15 is shown.
k) and the input IN ₂ output from the FFT analyzer 24
Is multiplied by the multiplier 17 with the complex data Y (k) of the spectrum to obtain a cross spectrum X ^* (k) Y (k). The cross spectrum X ^* (k) Y (k) is stored in the register 31b. Will be remembered.

Here, the registers 31a, 31b, 3
1c is one of N corresponding to the number of times N of the average power spectrum of the N input IN ₁ X ^* (
k) X (k), power spectrum Y ^* of input IN ₂
k) Y (k) and cross spectrum X ^* (k) Y
(K) are respectively stored.

Thereafter, the registers 31a, 31b, 3
Each stored power spectrum of the N input IN ₁ X ^* to 1c (k) X (k) , the cross-spectrum X ^* (
k) Y (k), and the input IN ₂ power spectrum Y ^*
(k) Y (k) is the corresponding averaging circuit 32
a, 32b, and 32c, and the average value P ₁ (k) of the power spectrum of the input IN ₁ , the average value C (k) of the cross spectrum, and the average value P ₂ (k) of the power spectrum of the input IN _2. Is calculated.

[0041] Here, the average value P ₁ of the power spectrum of the input IN ₁ (k) is expressed by equation (2), the input IN ₂
The average value P ₂ (k) of the power spectrum is expressed by equation (3), and the average value C (k) of the cross spectrum is expressed by equation (4).

[0042]

(Equation 1)

[0043]

(Equation 2)

[0044]

(Equation 3)

The average value P ₁ (k) of the power spectrum and the average value C (k) of the cross spectrum of the input IN ₁ are sent to a transfer function calculator 35.
, The transfer function H (k) of the device under test is calculated. Specifically, the amplitude and the phase are calculated as a transfer function.
The value of this transfer function is output from the output terminal 39.

The transfer function H (k) including the amplitude and the phase is represented by the following equation (5), and the transfer function H (k) having only the amplitude is provided.
Is represented by the following equation (6).

[0047]

(Equation 4)

[0048]

(Equation 5)

The average value P ₁ (k) of the power spectrum of the input IN ₁ , the average value P ₂ (k) of the power spectrum of the input IN ₂ , and the average value C of the cross spectrum
(K) is sent to the coherence calculator 34.

The average value C (k) of the cross spectrum obtained by the averaging circuit 32b is sent to the complex conjugate converter 33, and the complex conjugate data C ^* of the average value C (k) of the cross spectrum is obtained ^. (k) is obtained, and the complex conjugate data C ^* (of the average value C (k) of the cross spectrum is obtained.
k) is also sent to the coherence calculator 34.

The coherence calculator 34 calculates the average value P ₁ (k) of the power spectrum of the input IN ₁ , the average value P ₂ (k) of the power spectrum of the input IN ₂ , and the average value C (k) of the cross spectrum. , And the complex conjugate data C ^* (k) of the average value C (k) of the cross spectrum,
Coherence, a property of waves that interfere with each other, so-called coherence is required. Assuming that the coherence is r, the coherence r is represented by the following equation (7).

[0052]

(Equation 6)

[0053] Here, the data in the frequency point of the data, as a result measuring only transfer characteristics of the frequency component when the level and the coherence of the average value of the power spectrum of the input IN ₁ of the signal is equal to or higher than a predetermined value To update.

If the measurement of the next acoustic characteristic is continued, the signals of the input IN ₁ and the input IN ₂ are fetched again, and the above processing is repeated.

[0055] In Figure 1, by controlling the switching of the acoustics measuring instrument signal by the control signal from the 45 switching unit 46 first inputs the output from the microphone amplifier 47 ₁ to acoustics measuring instrument 45, measuring transfer characteristic of the use microphones MC ₁ is measured. Thereafter, by controlling the switching of the signal switch 46, the microphone amplifiers 47 ₂ , 47 ₃ , 47
_4, 47 ₅ Output sequentially selects from the measuring microphone M
The transfer characteristics of C ₂ , MC ₃ , MC ₄ and MC ₅ are measured, respectively.

The acoustic characteristic measuring device 45 performs averaging by adding the values of the measurement results for each frequency point in one measurement microphone, and further adds the measurement results of all the measurement microphones. Averaging, and one measurement result is displayed as acoustic characteristics.

Next, the measurement procedure of the acoustic characteristics will be described with reference to the flowchart of the measurement procedure of the acoustic characteristic measuring apparatus shown in FIG.

First, switching of output from the microphone amplifier is selected in step S21, and in step S22, the input IN is selected.
_In consideration of the case where the signal of the input IN ₂ is delayed beyond the range of the number of points of the fast Fourier transform with respect to the signal of ₁ , the signal of the input IN ₁ is delayed from the head of the corrected signal data. Set the delay time to take out.

[0059] Thereafter, in step S23, the digital conversion takes in the analog audio signal from the input IN ₁ and the input IN _2, takes out the number of samples required for measuring acoustic characteristics from the digital signal.

[0060] Then, in step S24, is multiplied by a window function to the signal input IN _1, determine the frequency spectrum of the input IN ₁ of the signal by performing FFT processing on this output, also the window function to the signal input IN ₂ multiplying the obtained frequency spectrum of the input iN ₂ of the signal by performing FFT processing on this output. Further, by using the frequency spectrum of the signal of the input IN ₁ and the input IN ₂ of the signal to calculate the respective power spectrum, cross spectrum using the power spectrum of the input IN ₂ and the power spectrum of the input IN ₁ which is the calculated Is calculated.

[0061] The power spectrum of the input IN _1, the power spectrum of the input IN _2, and to determine the number of times the N content averaging the cross spectrum, step S25
In, it is determined whether or not the processing operation in step S24 has been performed N times. Thereby, the input IN ₁ and the input IN ₂
Are obtained as many times as the average of the respective values of the power spectrum and the cross spectrum.

[0062] Thereafter, in step S26, the average power spectrum of the number of the input IN ₁ of obtained power spectrum of the input IN _2, and using the values of the cross spectrum, the power spectrum of the input IN _1, input The average value of the power spectrum of IN ₂ and the average value of the cross spectrum are calculated.

[0063] Then, in step S27, the power spectrum of the input IN _1, the power spectrum of the input IN _2, and using the average value of the cross-spectral determine the value of the coherence. Moreover, to calculate the transfer function using the average value of the power spectrum and the cross spectrum of the input IN _1.

Further, in step S28, using the coherence value and the transfer function obtained for each frequency point,
A transfer function is averaged for each frequency point to obtain an average value by a reliability determination process described later, and the acoustic characteristics of one measurement microphone are displayed on an external display device.

Thereafter, returning to step S21, the output of the microphone amplifier is switched and the operations in steps S22 to S28 are performed, whereby the measurement microphone MC _{1 in} FIG.
Determining and displaying the respective transfer function to MC _5.

[0066] Then, the process proceeds to step S29, the measurement performed averaging using the average value of the transfer function for each frequency point in the microphone MC ₁ to MC _5, the average value of one transfer function at each frequency point Is obtained and displayed as acoustic characteristics.

Thereafter, if the averaging operation is turned off in step S30, the operation of measuring the acoustic characteristics is terminated. If the acoustic characteristics are further measured, the operation proceeds to step S30.
Returning to step 21, the measurement microphone is switched and selected, and step S2 is performed.
The operations from 2 to S28 are performed, and in step S29, the average value of the transfer function of each measurement microphone is averaged.

Next, FIG. 4 shows a flowchart of the procedure of the reliability judgment processing for each frequency point, which will be described below.

First, in step S41, it is determined whether or not the obtained coherence value is equal to or more than a certain value. If it is equal to or more than the certain value, it is determined to be "OK". And If the result of this determination is “OK”, the flow advances to step S42 to determine whether or not averaging is set.
If G ′ is reached, the process proceeds to step S46, and it is determined whether or not averaging is set.

If it is determined in step S46 that the averaging is not set, the process ends without performing any operation.

If it is determined in step S42 that averaging is not performed, the flow advances to step S50 to display the transfer function of the currently obtained frequency point as an acoustic characteristic on an external display device. I do.

If it is determined in step S42 that averaging is to be performed, the obtained transfer function is stored, and the flow advances to step S43 to determine the transfer function of "OK". The number of data is compared with the number of data set for averaging. As a result of this comparison, when the number of data set to 'OK' is less than the number of data set for performing averaging, the process proceeds to step S44 to add data, and the total value of the data is obtained in step S45. Averaging by the number of data is performed. Then, the average value of the transfer function data obtained by the averaging is displayed as an acoustic characteristic in step S50.

If it is determined in step S43 that the number of data set to "OK" is the same as the number of data set for performing averaging, the process proceeds to step S48, where the oldest data is discarded. The measured new data is stored, the total of the data values is obtained in step S49, and averaging is performed by the number of averaging.
Then, the average value of the transfer function data obtained by the averaging is displayed as an acoustic characteristic in step S50.

If it is determined in step S46 that averaging is set, the flow advances to step S47 to determine whether or not there is data that has been set to "OK". If it is determined that there is no data set to 'OK', the process is terminated without performing anything. If it is determined that there is data that is "OK", the process proceeds to step S45, where the sum of the data values is obtained, and averaging is performed based on the number of data. And
The average value of the data obtained by this averaging is
It is displayed as an acoustic characteristic in step S50.

The above-described reliability determination processing is performed for each frequency point.

In the above acoustic characteristic measuring apparatus, one acoustic characteristic is obtained by averaging the acoustic characteristics of a plurality of measuring microphones. It is also possible to select as an acoustic characteristic in the device.

[0077]

As is apparent from the above description, the acoustic characteristic measuring apparatus according to the present invention comprises an orthogonal transform means for performing an orthogonal transform process on an input signal and an output signal, and an input signal and a signal from the orthogonal transform means. A spectrum for calculating each power spectrum of the input signal and the output signal using each spectrum of the output signal, and calculating an average value of the power spectrum of the input signal and the output signal using each power spectrum of the input signal and the output signal. Calculating means; transfer characteristic calculating means for calculating a transfer characteristic of each frequency component using an average value of power spectra of the input signal and output signal from the spectrum calculating means; and the plurality of measurements from the transfer characteristic calculating means. Characteristic means for averaging the average value of the transfer characteristics for each microphone for obtaining the acoustic characteristics, You can easily adjust the raw device.

Here, coherence calculating means for calculating a coherence value using the average value of the power spectrum and the average value of the cross spectrum of the input signal and the output signal, and each frequency component from the transfer characteristic calculating means. Averaging means for averaging only the transfer characteristic of the component of the frequency at which the value of the coherence from the coherence calculating means is equal to or greater than a predetermined value, wherein the acoustic characteristic calculating means comprises: By averaging the average value of the transfer characteristics of each of the plurality of measurement microphones from the converting means, the reliability of the transfer function to be obtained can be improved.

Further, the acoustic characteristic measuring device according to the present invention
Orthogonal transform means for performing orthogonal transform processing on the input signal and the output signal, and calculating each power spectrum of the input signal and the output signal using each spectrum of the input signal and the output signal from the orthogonal transform means, And a spectrum calculating means for calculating an average value of the power spectrum of the input signal and the output signal using each power spectrum of the output signal, and an average value of the power spectrum of the input signal and the output signal from the spectrum calculating means. A transfer characteristic calculating means for calculating a transfer characteristic of a frequency component, and an average value of a transfer characteristic of at least one measurement microphone is independently obtained from an average value of the transfer characteristics for each of the plurality of measurement microphones from the transfer characteristic calculation means. And the acoustic characteristic calculation means for extracting the acoustic characteristics. Can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an acoustic characteristic measuring device according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of an acoustic characteristic measuring device.

FIG. 3 is a flowchart of a procedure for measuring acoustic characteristics.

FIG. 4 is a flowchart of a reliability determination processing procedure.

FIG. 5 is a flowchart of a conventional procedure for measuring acoustic characteristics.

FIG. 6 is a diagram for explaining an acoustic characteristic measurement signal.

[Explanation of symbols]

 12, 22 Window function generator 14, 24 FFT analyzer 15, 25, 33 Complex conjugate converter 31a, 31b, 31c Register 32a, 32b, 32c Averaging circuit 34 Coherence calculator 35 Transfer function calculator 42 Equalizer 43 Power Amplifier 44 Speaker 45 Acoustic characteristic measuring device 46 Signal switch 47 Microphone amplifier

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01H 17/00

Claims (5)

(57) [Claims] 1. An acoustic characteristic measuring device which converts an input signal and the input signal into an acoustic signal, and calculates acoustic characteristics by using a plurality of output signals obtained by being collected by a plurality of measurement microphones. orthogonal transformation means for performing orthogonal transform processing to the input and output signals, each of the power spectrum of the input signal and the output signal using a respective space <br/> spectrum of the input signal及beauty output signal from the orthogonal transform means is calculated, and spectrum calculating means for calculating an average value of the power spectrum of the input signal and the output signal with the power spectrum of the input signal and output signal, the power spectrum of the input signal and the output signal from said spectrum calculating means a transfer characteristic calculation means for calculating the transfer characteristic of each frequency component by using the average of, the plurality of measurement for each microphone from the transfer characteristic calculation means And an acoustic characteristic calculating unit for averaging the average value of the transfer characteristics of the acoustic characteristics to obtain an acoustic characteristic. 2. The apparatus according to claim 2 , wherein
Spectrum of input signal and output signal from orthogonal transformation means
The cross spectrum is calculated from the
Cross-spectrum of the above input and output signals using
The transfer characteristic calculating means calculates the average value of the spectrum
Average of the power spectra of their input and output signals
Frequency and the average value of the cross spectrum.
2. The transmission characteristic of a minute is calculated.
Acoustic characteristic measuring device. Wherein further the average value of the power spectrum of the input signal and output signal, and a coherence calculation means for calculating the value of the coherence with the average value of the cross spectrum, of each frequency component from the transfer characteristic calculation means Transfer characteristics
On the other hand, the coherence from the coherence calculation means
Only the transfer characteristics of the frequency components whose
Averaging means for equalizing , wherein the acoustic characteristic calculating means comprises:
The average value of the transfer characteristics for each microphone
The acoustic characteristic measuring device according to claim 2 , wherein the acoustic characteristic is obtained . 4. An acoustic characteristic measuring apparatus which converts an input signal and the input signal into an acoustic signal, and calculates acoustic characteristics by using a plurality of output signals obtained by a plurality of measurement microphones. orthogonal transformation means for performing orthogonal transform processing to the input and output signals, each of the power spectrum of the input signal and the output signal using a respective space <br/> spectrum of the input signal及beauty output signal from the orthogonal transform means is calculated, and spectrum calculating means for calculating an average value of the power spectrum of the input signal and the output signal with the power spectrum of the input signal and output signal, the power spectrum of the input signal and the output signal from said spectrum calculating means a transfer characteristic calculation means for calculating a transfer characteristic of each frequency component by using the average value of the plurality of measurement for each microphone from the transfer characteristic calculation means An acoustic characteristic calculating means for independently extracting an average value of the transfer characteristics of at least one measurement microphone from the average value of the transfer characteristics of the acoustic characteristics. 5. The apparatus according to claim 1, wherein said spectrum calculation means further comprises:
Spectrum of input signal and output signal from orthogonal transformation means
The cross spectrum is calculated from the
Cross-spectrum of the above input and output signals using
The transfer characteristic calculating means calculates the average value of the spectrum
Average of the power spectra of their input and output signals
Frequency and the average value of the cross spectrum.
5. The transmission characteristic of a minute is calculated.
Acoustic characteristic measuring device.