JPH0628326B2 - Equalizer device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an equalizer device (hereinafter referred to as an equalizer) for automatically correcting a sound field in an audio device.

Configuration of Conventional Example and Problems Thereof In recent years, an equalizer for correcting a sound field or an equalizer for automatically performing the same has been widely used.

Next, a conventional equalizer will be described. Figure 1 is a block diagram of a conventional equalizer. (1) is the input terminal, (11)
~ (1n) is a band pass filter, (21) ~ (2n) is a level adjuster, (30) is a full adder, (40) is an adder, (50) is a demultiplexer, (60) is an oscillator, ( 70) is a microphone, (80) is a microphone amplifier, (90) is a rectifying / smoothing device, (100) is an analog / digital converter (hereinafter referred to as AD converter), (110) is an interface, (120) is a microcomputer, (13
(0) is a random access memory (hereinafter referred to as RAM), (140) is a read only memory (hereinafter referred to as ROM), (150) is an input operation unit, (160) is an output terminal, and (17)
0) is an amplifier and (180) is a speaker.

The following operations of the equalizer configured as described above will be described. First, the oscillator (60) oscillates a narrow band signal corresponding to the frequency of the i-th band in the band divided by the band pass filter groups (11) to (1n), and the adder (4
0) and output from the speaker (180) via the amplifier (170). Then, the output of the speaker (180) is picked up by the microphone (70), the signal is amplified by the microphone amplifier (80), and the
The signal is converted to DC at (90), the analog signal is converted to a digital signal at the AD converter (100), and the interface (1
The microcomputer (120) calculates the complement of the value via (10) and stores the complement value in the corresponding location of the RAM (130). After performing the above operation over the entire band (i = 1 to n), the complement of the input level of each band stored in the RAM (130) is supported via the interface (110) and demultiplexer (50). Level adjuster (21)
To (2n) as a control signal, and level adjusters (21) to (2
Sound field correction is performed by setting n).

However, in the above-mentioned conventional method, since there is mutual interference between the bandpass filters that occurs because the bandpass filter groups (11) to (1n) are not ideal bandpass filters, there is a problem that the sound field correction cannot be performed well. Had.
The problem of this conventional example will be described with reference to FIG. Fig. 2 (a) is a characteristic diagram of each band with all bands set to 0 (dB), Fig. 2 (b)
Is the overall characteristic diagram of Fig. 2 (a), and Fig. 2 (c) is the third band +
A characteristic diagram of each band in which the remaining band of 3 [dB] is set to 0 [dB], and FIG. 2 (d) is an overall characteristic diagram of FIG. 2 (c). From FIG. 2, the third due to mutual interference between the bandpass filters,
When the band characteristics are lifted as shown in Fig. 2 (c), Fig. 2
It is observed that the characteristics of the adjacent bands also rise as in (d). Therefore, the sound field correction is not successful.
The above problems also occur when a wide band signal such as pink noise is used as the reference signal (Japanese Patent Laid-Open No. 57-140012 "auto equalizer", Japanese Utility Model Laid-Open No. 58-26217 "automatic equalizer device"). Occur.

An object of the present invention is to solve the above-mentioned conventional problems, and by using a narrow band signal as a reference signal, there is no annoyance during measurement of sound field characteristics, and even when a narrow band signal is used as a reference signal. An object of the present invention is to provide an equalizer device capable of eliminating incomplete sound field correction caused by mutual interference between band pass filters.

To achieve the above object, the present invention has a frequency band dividing unit that divides a frequency band into a plurality of units, and a level adjusting unit that adjusts the level of a signal of each frequency band divided by the frequency band dividing unit. A reference signal generation unit that sequentially generates a narrow band signal as a reference signal over the entire frequency band and supplies it to the frequency band division unit, and a sound collection that collects the reference signal acoustically converted through the frequency band division unit. Means and a coefficient to be set in the level adjusting means for each frequency are stored in a first storage area, and a level of a reference signal of each frequency collected by the sound collecting means is stored in a second storage area. Means, a variance measuring means for obtaining the variance of the values stored in the second storage area of the storage means, and each circumference stored in the first storage area of the storage means. Based on the coefficient of the wave number level adjusting means and the level of the reference signal of each frequency collected by the sound collecting means stored in the second storage area of the storage means,
Subtracting the contents of the second storage area of the storage means from the contents of the first storage area of the storage means for each frequency,
Arithmetic means for adding the average value of the contents of the second storage area of the storage means at all frequencies, and storing the result in the first storage area of the storage means as a coefficient of the level adjusting means for each new frequency; Setting means for setting the coefficient stored in the first storage area of the storage means in the level adjusting means, the setting means being the first of the storage means.
The coefficient stored in the storage area is set in the level adjusting means, the reference signal generating means sequentially generates narrow band signals over the entire frequency band through the frequency band dividing means, and the sound collecting means collects. The level of the sounded reference signal of each frequency is stored in the second storage area of the storage means,
If the variance of the values stored in the second storage area of the storage means obtained by the variance measuring means is small, the process ends. If the variance is large, the value is stored in the first storage area of the storage device. The calculation based on the coefficient of the level adjusting means of each frequency being recorded and the level of the reference signal of each frequency collected by the sound collecting means stored in the second storage area of the storage means. The level adjustment for each frequency is performed by subtracting the level of the reference signal at each frequency from the coefficient of the level adjustment means for each frequency and adding the average value of the levels of the reference signal at each frequency at all frequencies. The coefficient of the means is obtained and stored in the first storage area of the storage means, and the processing is returned to the initial processing, whereby the effect of mutual interference of the frequency band dividing means is eliminated, and accurate sound field correction is easily performed. Na It is obtained by way.

Description of Embodiments Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram of the automatic equalizer in one embodiment of the present invention. In FIG. 3, those having the same numbers as those in FIG. 1 perform the same operation. The difference is that the switch (2
00) is interposed between the input terminal (1) and the bandpass filters (11) to (1n), and the oscillator (210) is connected to the other terminal of the switch (200).

The operation of the equalizer having the above-described structure according to this embodiment will be described below.

First, the switch (200) is tilted to the oscillator (210) side, and the coefficients of the level adjuster groups (21) to (2n) are all set to 0 (midpoint). Secondly, a control signal is sent from the microcomputer (120) to the oscillator (210) via the interface (110) to oscillate a narrow band signal corresponding to the frequency of the i-th band, and the switch (200) and band pass. Filter group (11) to (1n)
, The level adjuster group (21) to (2n), the full adder (30), the output terminal (160), the amplifier (170), the speaker (180), and the output from the microphone (70). The sound is picked up, the signal is amplified by the microphone amplifier (80), the signal is converted to DC by the rectification smoother (90), the analog signal is converted to a digital signal by the AD converter (100), and the interface (110 ), The microcomputer (120) reads the information, calculates the complement, and stores the value in the location i (M (1, i)) of the first area of the RAM (130). . The above second operation is performed over the entire band (i = 1 to n).

Thirdly, the value stored in the first area of the RAM (130) is passed through the microcomputer (120), the interface (110) and the demultiplexer (50) to the level adjuster group () of the corresponding band. 21) Set the coefficient of (2n).

Fourth, send a control signal from the microcomputer (120) to the oscillator (210) via the interface (110),
A narrow band signal corresponding to the frequency of the i-th band is oscillated, and a switch (200), band pass filter groups (11) to (1n), level adjuster groups (21) to (2n), full adder (30) , Output terminal (160)
, Output from the speaker (180) via the amplifier (170), the output is picked up by the microphone (70), microphone amplifier (80), rectifying and smoothing device (90), AD converter (100), interface (110), via the microcomputer (120), the location of i in the second area of the RAM (130) (M (2,
i)). The above fourth operation is applied to the entire band (i = 1
~ N).

Fifthly, if the difference in the level of each band stored in the second area of the RAM (130) is within a certain range, the process is terminated,
If it is not within a certain range, the value of the place corresponding to the i-th band of the second area of RAM (130) is subtracted from the average value of the second area of RAM (130), and that value is stored in RAM (130). First
The operation of adding to the value of the place corresponding to the i-th band of the area is performed by changing i from 1 to n, and the procedure returns to the third operation.

FIG. 4 shows a flow chart of the equalizer microcomputer in one embodiment of the present invention, and the control procedure thereof will be described below. First, the coefficient of the level adjuster for all bands is set to 0, and secondly, the narrow band signal corresponding to the i-th band and the frequency is oscillated from the oscillator, the level is taken in, the complement of the value is taken, and M It is stored in (1, i), the above second operation is performed over all bands (i = 1 to n), and the third operation is performed.
The value stored in M (1, i) is given as a coefficient of the level adjuster for the i-th band, and the above third operation is performed for all bands (i = 1
To n), fourthly, oscillate a narrow band signal corresponding to the frequency of the i-th band from the oscillator, take in the level, and store the value in M (2, i), Is performed over all bands (i = 1 to n), and fifthly M
If the difference of n values from (2, i) to M (2, n) is smaller than a certain value, it ends, and if it is larger than a certain value, it is set to M (1, i). Value is stored, this is performed over all bands (i = 1 to n), and the process returns to the third operation.

FIG. 5 shows an equalizer device according to an embodiment of the present invention.
The first area M (1, i) of the RAM 130 (i = 1 to 1
n) and the level adjuster group (21)
Equalizer characteristics set to (2n), and R
Second area M (2, i) of AM130 (i = 1 to n)
3 schematically shows the level of each frequency band in which the reference signal of each band is picked up from the microphone 70 stored in FIG. In the present embodiment, a case where n = 7 will be described.

In FIG. 5, (a) is stored in the first area M (1, i) (i = 1 to n) of the RAM 130 and set in the level adjuster groups (21) to (2n). Characteristics of the equalizer before correction, (b) is the first of the RAM 130
Is stored in the area M (1, i) (i = 1 to n) of the above and is set to the level adjuster groups (21) to (2n), the characteristic of the equalizer after the one-time correction, (c) is RAM
The level adjuster groups (21) to (2) are stored in the first area M (1, i) of 130 (i = 1 to n) and are stored.
the characteristics of the equalizer after the two-time correction set to n),
(D) is the second area M (2, i) (i of the RAM 130
= 1 to n) the microphone 70 stored in
(E) is the second area M (2, i) of the RAM 130, the level of each band before correction in which the reference signal of each band is picked up from
The level of each band after once corrected by picking up the reference signal of each band from the microphone 70 stored in (i = 1 to n), (f) is the second area M of the RAM 130
(2, i) (i = 1 to n) is the level of each band after being corrected twice by collecting the reference signal of each band from the microphone 70.

First, as an initial state, as shown in (a), it is stored in the first area M (1, i) (i = 1 to n) of the RAM 130 and set in the level adjuster groups (21) to (2n). When all the coefficients set to the equalizer are 0 (midpoint), the level of each band in which the narrow band signal of each band (1 to n) generated by the oscillator 210 as the reference signal is picked up from the microphone 70 is It is assumed that the level of the fourth band (= 14.0) is higher than the levels of other bands (= 10.0) as shown in (d).

Next, as the first correction, based on the level (d) of each band picked up before correction and the coefficient (a) of the equalizer characteristic before correction, each band is calculated from the average value (= 10.6) of all bands. When a value obtained by subtracting the level (d) of the above is added to the equalizer characteristic (a) before correction, an equalizer that lowers the level of the fourth band as compared with other bands as shown in (b) compared to (a) It becomes a characteristic.

The equalizer characteristic (b) is stored again in the first area M (1, i) (i = 1 to n) of the RAM 130, and
The level adjuster groups (21) to (2n) are reset, and each frequency (1 to 1) generated again by the oscillator 210 as the reference signal is reset.
When the narrow band signal of n) is picked up from the microphone 70,
As in (e), the level of the fourth band is lower than that in (d). Here, the interference from the adjacent band pass filter is 1
/ 3. For example, the level of the fourth band in which the reference signal of the fourth band is picked up from the microphone 70 is 14.0.
-3.4 + 0.6 / 3 + 0.6 / 3 = 11.0.

However, the interference between the bandpass filters also lowers the levels of the third band and the fifth band on both sides of the fourth band. When it is determined that the level difference δ2 (= 1.3) of each frequency band at this time is larger than a certain threshold δ (= 1.0),
Make a second correction.

Then, as the second correction, the value obtained by subtracting the level of each band from the average value (= 10.6) of all bands based on the level information of each band collected after the first correction of (e) is set to 1 When added to the equalizer characteristic (b) after the time correction,
As compared to (b), as shown in (c), the level of the third band and the fifth band
It becomes the characteristic of the equalizer that raises the band level.
The equalizer characteristic (c) is stored again in the first area M (1, i) (i = 1 to n) of the RAM 130, and
The level adjuster groups (21) to (2n) are reset, and each frequency (1 to 1) generated again by the oscillator 210 as the reference signal is reset.
When the narrow band signal of n) is picked up from the microphone 70,
As in (f), the levels of the third band and the fifth band are higher than those of (e). If it is determined that the level difference δ3 (= 0.9) of each frequency band at this time is smaller than a certain threshold δ (= 1.0), the process ends. Therefore, each time the correction is repeated, the difference in the level of each frequency band gradually becomes smaller (δ1>δ2> δ3), so the overall frequency characteristics including the acoustic equipment and acoustic space become flat, and accurate sound field correction is performed. It can be performed.

As described above, according to the present embodiment, the narrow band signal of each band is oscillated, its level is taken in, the level adjuster of each band is set by its complement, and then the narrow band signal of each band is oscillated again. , By taking in the level, checking the level difference of each band, ending if it is small, and resetting the level adjuster based on the information of that level if the difference is large, the band pass Accurate sound field correction can be performed by removing the influence of mutual interference between filters.

EFFECTS OF THE INVENTION According to the present invention, the reference signal of each frequency is generated, the sound is picked up, and if the difference between the levels of the picked-up frequencies is larger than a certain value, based on the level of each frequency. Correct the equalizer and return to the process of generating the reference signal, while on the other hand, if the difference between the levels of the picked-up frequencies is smaller than a certain value, the process ends, so it is not necessary to generate an annoying wideband signal during adjustment Further, it is possible to realize an excellent equalizer that can remove the effect of mutual interference between the band pass filters and obtain the effect that the sound field can be corrected accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional equalizer, FIG. 2 is a diagram showing mutual interference between bandpass filters, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is an embodiment of the present invention. Flowchart of Microcomputer in Figure 5, Fig. 5 (a)
Is the characteristic diagram of the equalizer before modification, (b) is the characteristic diagram of the equalizer after one modification, (c) is the characteristic diagram of the equalizer after two modifications, and (d) is the characteristics of each band before modification. Diagram showing levels,
The same (e) is a diagram showing the level of each band after one correction, and the same (f)
FIG. 6 is a diagram showing the level of each band after being corrected twice. (11) ~ (1n) ... band pass filter, (21) ~ (2n) ... level adjuster, (30) ... full adder, (50) ... demultiplexer, (70) ... microphone, (90) …… Rectifier smoother, (1
00) ... AD converter, (110) ... interface, (1
20) ... Microcomputer, (130) ... RAM, (1
40) …… ROM, (150) …… Input operation part, (180) …… Speaker.

Claims (1)

[Claims] 1. A frequency band dividing means for dividing a frequency band into a plurality of parts, a level adjusting means for adjusting a level of a signal of each frequency band divided by the frequency band dividing means, and a narrow band signal as a reference signal. Reference signal generating means for sequentially generating over the entire frequency band and supplying the frequency band dividing means, sound collecting means for collecting the reference signal acoustically converted through the frequency band dividing means, and Storage means for storing the coefficient set in the level adjusting means in the first storage area, and storing the level of the reference signal of each frequency picked up by the sound collecting means in the second storage area; The relationship between the variance measuring means for obtaining the variance of the values stored in the second storage area and the level adjusting means for each frequency stored in the first storage area of the storage means. And the level of the reference signal of each frequency picked up by the sound pickup unit stored in the second storage area of the storage unit, the first storage area of the storage unit for each frequency. Content of the second storage area of the storage means is subtracted from the content of, and an average value of the contents of the second storage area of the storage means at all frequencies is added, and the result is added to the level adjustment means of each new frequency. And a setting unit configured to store the coefficient stored in the first storage area of the storage unit as a coefficient in the level adjustment unit. Sets the coefficient stored in the first storage area of the storage means in the level adjusting means, and the reference signal generating means passes the narrow band signal over the entire frequency band through the frequency band dividing means. The second storage area of the storage means obtained by the dispersion measuring means for storing the levels of the reference signals of the respective frequencies collected by the sound collection means in the second storage area of the storage means. If the variance of the value stored in the storage unit is small, the process ends. If the variance is large, the coefficient of the level adjusting unit of each frequency stored in the first storage area of the storage unit and the storage unit. On the basis of the level of the reference signal of each frequency collected by the sound collecting means stored in the second storage area of
The calculating means subtracts the level of the reference signal of each frequency from the coefficient of the level adjusting means of each frequency for each frequency, and adds the average value of the levels of the reference signal of each frequency at all frequencies. An equalizer device, characterized in that a coefficient of a level adjusting means is obtained and stored in a first storage area of the storage means, and the processing is returned to the initial processing.