JPH0628011A - Active control device using adaptive iir digital filter - Google Patents

Abstract

PURPOSE:To improve the stability of a filter in the case of updating the filter coefficient of an adaptive IIR (infinite impulse response) digital filter. CONSTITUTION:This active control device has a coefficient control part 21 for updating the filter coefficient of the adaptive IIR digital filter 16 so as to minimize an output error signal level and a coefficient control part 19 for updating the filter coefficient of a circulation part 17 and uses the filter 16 constituted so as to execute the updating of respective filter coefficients by the control parts 19, 21 in parallel or with time division.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active control device using an adaptive IIR digital filter, more specifically, an active noise control device, an active vibration control device, an echo canceller, a signal control circuit in an adaptive equalizer, and other active devices. The present invention relates to an active control device using an adaptive IIR digital filter used in a signal control circuit in general control.

[0002]

2. Description of the Related Art Generally, the transfer function H (z) of an adaptive IIR digital filter is expressed by the following equation 1.

[0003]

[Equation 01]

A direct type configuration of this adaptive type IIR digital filter is shown in FIG. Adaptive type II
The direct type configuration of the R digital filter has a unit delay element 2
8, the multiplier 29, and the adder 30. The input signal u is added by the adder 30 via the unit delay element 28 and the multiplier 29 and output as the output signal y. a (i) and b (j) indicate filter coefficients. Here, the transfer function H _N (z) is formed by the filter coefficient a (i).

[0005]

[Equation 02]

The FIR digital filter portion for realizing the above is replaced with the non-recursive portion 18 of the adaptive IIR digital filter 16.
, And is composed of the filter coefficient b (j), and the transfer function H _R (z)

[0007]

[Equation 03]

A portion that realizes the above is called a patrol unit 17.

When the input signal of the adaptive IIR digital filter 16 is u (n) and the output signal is y (n), the input / output relationship is expressed by the equation (4).

[0010]

[Formula 04]

Here, N is the number of taps of the non-recursive section 18, and M
Indicates the number of taps of the patrol unit 17. There are various filter coefficient updating algorithms, and one of them is a method of updating the filter coefficient according to the following equations (5) and (6).

[0012]

A (i, n + 1) = a (i, n) + αu (n-i) e (n)

[0013]

B (j, n + 1) = b (j, n) + βy (nj) e (n) where e (n) is the output of the desired response d (n) and the filter output y (n). The error d (n) -y (n) is shown, and α and β are step size parameters, which are small positive values. Further, there is a method of using f (n) shown in the following Expression 7 instead of e (n) in Expressions 5 and 6 in order to improve the stability and convergence of update of the filter coefficient.

[0014]

[Equation 07]

Here, c (l) represents the weight of the moving average and is a predetermined constant. Further, L indicates the number of pieces of data for which a moving average is taken.

The adaptive IIR digital filter 36 shown in FIG. 10 has a filter coefficient update control unit added to that shown in FIG. In the non-recursive unit 18, the input signal u (n) and the output error signal e (n) are transferred to the coefficient control unit 2
The coefficient control unit 20 is connected so that a control signal is input to each multiplier 29. On the other hand, also on the circulation unit 17 side, the output signal y (n) and the output error signal e (n) are input to the coefficient control unit 21 and the coefficient control unit 21.
Is connected so that a control signal is input to each multiplier 29. When using Equation 7, and u (n- of Equation 5)
i), when the following equations 8 and 9 are used instead of y (n−j) in equation 6, the configuration is basically as shown in FIG. It can be processed.

[0017]

[Equation 08]

[0018]

[Equation 09]

A signal processing unit of an active silencer that suppresses noise by radiating sound waves with the same amplitude, which are 180 ° out of phase with noise, from the sound deadening sounding means to cause sound wave interference, and the adaptive type as described above. IIR digital filter 1
FIG. 11 shows the configuration when Nos. 6 and 36 are applied. Figure 11
In the figure, reference numeral 12 denotes a container having an opening at one end, and the noise from the noise source 11 arranged in the container 12 is detected by the noise detection microphone 13. The detection signal detected by the noise microphone 13 is digitally converted by the A / D converter 25 via the preamplifier 22 and input to the adaptive IIR digital filter 16. Noise detection microphone 13
The adaptive IIR digital filter 16 performs an operation on the input signal u (n) detected by the equation (4), and the operation result y (n) is output as a mute signal to the D / A converter 26 and the power amplifier 23. It is output from the muffling speaker 15 via the.
The filter coefficient a (i) of the non-cyclic section 18 and the filter coefficient b of the cyclic section 17 of the adaptive IIR digital filter 16
(j) is the coefficient control unit 2 via the preamplifier 24 and the A / D converter 27 according to the muffling error signal −e (n) detected by the muffling error detecting microphone 14 in the container 12.
The coefficient control unit 2 based on the signals input to 0 and 21.
It is sequentially updated at 0 and 21. Also noise microphone 13
The detection signal detected in (1) is input to the coefficient control unit 20 via the digital filter 32 without passing through the adaptive IIR digital filter 16, and the silencing signal does not pass through the silencing error detecting microphone 14. Direct adaptation type II
R digital filter 16 to digital filter 31
Is input to the coefficient control unit 21 via.

If the equations (5) and (6) are used here, the updating formula is expressed by the following equations (10) and (11).

[0021]

## EQU10 ## a (i, n + 1) = a (i, n) + αu ₁ (ni) e (n)

[0022]

B (j, n + 1) = b (j, n) + βy ₁ (nj) e (n) u ₁ (n) is a digital filter of the input signal u (n) of the adaptive IIR digital filter 16. 32, and y ₁ (n) is the output signal y (n) of the adaptive IIR digital filter 16 corrected by the digital filter 31. The characteristics of the digital filters 31 and 32 are that the output of the adaptive IIR digital filter 16 passes through the muffling error detection microphone 14, and the coefficient control units 20 and 2 respectively.
It is a transfer characteristic up to 1.

Still another conventional example is the one shown in FIG. When the desired response d is directly obtained, the input signal u is calculated in the non-cyclic section 18 and the cyclic section 17 of the adaptive IIR digital filter 16, and the calculation result y is output as a mute signal, and the mute signal and the desired response d are output. And are compared. Then, a signal corresponding to the muffling error signal e is input to each of the coefficient control units 20 and 21, and the output signal y is transmitted via the circulation unit 17 to the coefficient control unit 2.
0, the input signal u is input to the coefficient control unit 21 via the cyclic unit 17, and the filter coefficient of the non-cyclic unit is updated. In this way, u ₀ (i, n) and y ₀ (j, n) of _equations 8 and 9 are used instead of u (ni), y (nj) of equations 5 and 6.

[0024]

As shown in FIG. 10, in updating the filter coefficient of the adaptive IIR digital filter 36 having the circulation unit 17, the problems of stability and convergence of the filter always occur. Even in the above-described various filter coefficient updating methods, stability and convergence are not guaranteed. The cyclic section 17 of the adaptive IIR digital filter 36 sometimes has a problem that its output diverges in the process of updating the filter coefficient. On the other hand, the circuit section 1 that minimizes the level of the output of the circuit section or the output of the adaptive IIR digital filter 36.
When the update of the filter coefficient of No. 7 is executed in parallel, it is possible to suppress the divergence of the signal in the circulation unit 17, but the input signal of the adaptive IIR digital filter 36 is periodic, and the cycle thereof is When a specific signal is required as the output of the adaptive IIR digital filter 36, there is a problem that the required periodic signal is canceled by the circulating unit.

Further, when the equations (10) and (11) are used, the amount of calculation becomes large, and high speed calculation is required regardless of the amount of calculation. In the application to active silence control,
As shown in FIG. 11, the digital filters 31 and 32 also need to be calculated as preprocessing of the coefficient control units 20 and 21, and there is a problem that an increase in the amount of calculation cannot be avoided.

The present invention has been invented in view of the above problems, and improves the stability and convergence in updating the filter coefficient of an adaptive IIR digital filter.
The calculation amount in the filter coefficient control unit is reduced, and the IIR
An object of the present invention is to provide an active control device using an adaptive IIR digital filter which can ensure the stability of a cyclic part when updating a filter coefficient of a digital filter and can cope with a periodic input. I am trying.

[0027]

In order to achieve the above object, an active control apparatus using an adaptive IIR digital filter according to the present invention detects a physical phenomenon quantity when controlling the physical phenomenon quantity to a desired quantity. Means, signal processing means for receiving a signal from the detecting means and performing a predetermined signal processing to output a control signal, and physical phenomenon output for receiving the control signal and converting the control signal into a physical phenomenon quantity Means and an error output means for outputting an error between a desired physical phenomenon amount and an actual physical phenomenon amount, and adapted to the signal processing means.
In an active control device using an R (Infinite Impulse Response) digital filter, a coefficient control unit that updates the filter coefficient so that the signal from the error output means is input and the error level is minimized, and the IIR digital filter An output signal or an output signal of the cyclic unit is input, and a coefficient control unit that updates the filter coefficient so as to minimize the signal level, and the update of the filter coefficient of the cyclic unit is performed by the coefficient control unit of both of them. (1) In order to achieve the above object, the active controller using the adaptive IIR digital filter according to the present invention controls the physical phenomenon amount to a desired amount. And a signal for receiving a signal from the detecting means for performing a predetermined signal processing and outputting a control signal. A processing means, a physical phenomenon output means for receiving the control signal and converting the control signal into a physical phenomenon quantity, and an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity. In the active control device using the adaptive IIR digital filter as the signal processing means, the cyclic section of the adaptive IIR digital filter is connected to the preceding stage of the non-cyclic section, and the output signal of the non-cyclic section and the error output means. An adaptive control unit for the filter coefficient in the cyclic unit that receives the error signal output by the output unit, and an output signal of the cyclic unit and a filter coefficient in the non-cyclic unit that receives the error signal output by the error output unit. An active control device using an adaptive IIR digital filter according to the present invention in order to achieve the above object (2), and an adaptive control unit. ,
The physical phenomenon quantity detecting means for controlling the physical phenomenon quantity to a desired quantity; the signal processing means for receiving a signal from the detecting means and performing a predetermined signal processing to output a control signal; The signal processing means includes a physical phenomenon output means for receiving a signal and converting the control signal into a physical phenomenon quantity, and an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity. In the active control device using the adaptive IIR digital filter, a first coefficient control section for updating the filter coefficient so that the signal from the error output means is input and the error level is minimized;
A second coefficient controller for receiving the output signal of the R digital filter or the output signal of the circulator and updating the filter coefficient so as to minimize the signal level; and the output signal of the IIR digital filter, or its A level detection unit that detects the level of the output signal of the cyclic unit, updating of the filter coefficient of the cyclic unit is controlled by the first and second coefficient control units, and the filter coefficient by the second coefficient control unit. The updating operation is configured to be permitted according to the signal level detected by the level detecting section (3).

[0028]

In the silencer shown in FIG. 11, when the conventional filter coefficient updating method is used, the signal may diverge in the circulating section 17. According to the configuration described in (1) of the present invention, the filter coefficient update that minimizes the output level of the cyclic unit is executed in parallel with respect to the filter coefficient of the cyclic unit. The signal divergence in the patrol section is suppressed. If the noise emitted by the noise source is a random sound, even if the filter coefficient of the patrol unit is updated so that the output level of the patrol unit is minimized, the noise signal is not canceled in the patrol unit. It becomes possible to exert a further effect. At this time, the sound radiated from the muffling speaker cancels a part of the signal component fed back to the noise detection microphone in the circuit.

According to the configuration described in (2) above,
For updating the filter coefficient of the non-recursive part of the adaptive IIR digital filter, F using the output of the cyclic part as an input signal is used.
IR (Finite Impulse Response) can be reduced to coefficient updating of a digital filter. The stability and convergence of the filter coefficient update of the FIR digital filter are guaranteed, and thus the stability and convergence of the filter coefficient update of the non-cyclic portion are guaranteed. Further, in the case of updating the filter coefficient using the equations 8 and 9, the calculation corresponding to the equation 8 in the present invention has already been performed in the cyclic unit, and it is not necessary to calculate again. Further, even if the order of the cyclic section and the non-cyclic section is exchanged as in the present invention, the filter is equivalent. Therefore, regarding the filter coefficient of the cyclic unit, it is possible to update the filter coefficient using the output of the non-cyclic unit and the output error signal corresponding to the output.

According to the configuration described in (3) above,
When the output level of the patrol unit becomes equal to or higher than a predetermined reference with respect to the filter coefficient of the patrol unit, it is possible to execute filter coefficient updating that minimizes the output level of the patrol unit in parallel. Since the level detector is provided, the signal divergence of the circuit is suppressed. Even when the noise generated by the noise source is a periodic sound, if the output level of the patrol unit does not exceed a predetermined reference, the filter coefficient that minimizes the output level of the patrol unit is not updated and is required. All the periodic signals that are generated are not canceled by the circulating unit, and it is possible to more effectively deal with periodic sounds.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an active control device using an adaptive IIR digital filter according to the present invention will be described below. It should be noted that components having the same functions as those of the conventional example are designated by the same reference numerals.

FIG. 1 is a block diagram showing an embodiment of an active control device using an adaptive IIR digital filter according to the present invention. A noise source 11 is arranged in a container 12 having an opening at one end, and a noise detection microphone 13 and a silencing error detection microphone 14 are arranged in the container 12 so as to face the noise source 11, and the side wall of the container 12 is arranged. A muffling speaker 15 is installed in the. The noise detected by the noise detection microphone 13 is converted into a digital signal by the A / D converter 25 via the preamplifier 22, and the converted noise signal u (n) is processed by the adaptive IIR digital filter 16. The calculation result is output to the D / A converter 26 as the muffling signal y (n). The mute signal converted into an analog signal by the D / A converter 26 is output from the speaker 15 via the power amplifier 23. The mute result is the mute error detection microphone 1
4 through the preamplifier 24 and the A / D converter 27 to obtain the muffling error signal -e (n) as coefficient control units 20 and 21.
Is taken into. The input u (n) of the acyclic unit 18 is also input to the digital filter 32, and the output u ₁ (n) of the digital filter 32 is input to the coefficient control unit 20. The output y (n) of the circulation unit 17 is also input to the digital filter 31, and the output y ₁ (n) of the digital filter 31 is also input to the coefficient control unit 21. Then, the filter coefficients a (i) and b (j) of the adaptive IIR digital filter 16 are updated so that the silencing error signal is minimized. The update formula at this time is expressed by the following formulas 10 and 11.

[0033]

## EQU10 ## a (i, n + 1) = a (i, n) + αu ₁ (ni) e (n)

[0034]

Equation 11] b (j, n + 1) = b (j, n) + βy 1 (nj) e (n) where alpha, and β denotes a step size parameter and takes a small positive value. In updating the filter coefficient b (j), f (n) in Eq. 7 can be used instead of e (n) in Eq. Also, y in the equation 11
Instead of ₁ (nj), y ₂ (j, n) of the following equation 12 can be used.

[0035]

[Equation 12]

It should be noted that the same result can be obtained even if the calculation unit of equation (12) occurs before the digital filter 31 and the order is changed. Further, the filter coefficient b of the patrol unit 17
The updating of (j) is also performed from the coefficient control unit 19. The coefficient control unit 19 inputs the output y (n) of the patrol unit 17, and outputs the output y (n).
The filter coefficient b (j) is updated by the following expression 13 so that the level of is minimized.

[0037]

[Mathematical formula-see original document] b (j, n + 1) = b (j, n)-[gamma] y (nj) y (n) where [gamma] represents a step size parameter, which is a small positive value. The update of the filter coefficient according to the equations 11 and 13 is executed in parallel or time-divisionally.

In the present embodiment, the updating of the filter coefficient is performed in parallel with respect to the filter coefficient of the circulating unit 17 so that the output level of the circulating unit 17 is minimized. Can be suppressed.
Further, when the noise is a random sound having no periodicity, the noise signal is not canceled by the patrol unit 17 even if the filter coefficient of the patrol unit 17 is updated so that the output level of the patrol unit 17 is minimized. At this time, the sound emitted from the muffling speaker 15 cancels a part of the signal component fed back to the noise detecting microphone 13, and a further muffling effect can be expected.

FIG. 2 is a block diagram showing a second embodiment of an active control device using an adaptive IIR digital filter according to the present invention. The hardware structure of this embodiment is the adaptive type shown in FIG. Circuit 17 in IIR digital filter 16
And the non-patrol unit 18 are simply replaced, and a detailed description of the hardware configuration will be omitted here.

In the present embodiment, the filter coefficient a (i) is updated by the coefficient control unit 20 by the following equation (14).

[0041]

A (i, n + 1) = a (i, n) + αv ₁ (ni) e (n) The filter coefficient b (j) is updated by the coefficient control unit 21 by the following Expression 11.

[0042]

Equation 11] b (j, n + 1) = b (j, n) + βy 1 (nj) e (n) Further, the cyclic portion 1 filter coefficients b (j) is a coefficient control unit 19
In order to minimize the level of output v (n) of 7
Updated by 5.

[0043]

B (j, n + 1) = b (j, n) -γv (nj) v (n) The update of the filter coefficient by the equations 11 and 15 is performed in parallel as in the case of the first embodiment. Is executed in a time-shared manner.

In this embodiment, the updating of the filter coefficient is performed in parallel with respect to the filter coefficient of the circulating unit 17 so as to minimize the output level of the circulating unit 17, so that the signal of the circulating unit 17 is updated. Can be suppressed.
Further, by changing the arrangement of the non-cyclic section 18 and the cyclic section 17, it is possible to improve the stability in updating the filter coefficient of the non-cyclic section 18. Further, as in the case of the above-described embodiment, when the noise is a random sound having no periodicity, even if the filter coefficient of the patrol unit 17 is updated so that the output level of the patrol unit 17 is minimized, the noise signal Is patrol section 1
The sound emitted from the muffling speaker 15 at this time cancels a part of the signal component fed back to the noise detection microphone 13, and a further muffling effect can be expected.

FIG. 3 is a block diagram showing a third embodiment of an active control device using an adaptive IIR digital filter according to the present invention. The hardware configuration of this embodiment is the adaptive IIR shown in FIG. The input of the coefficient control unit 9 of the digital filter is changed from the output v (n) of the cyclic unit to the output y (n) of the non-cyclic unit, and the detailed description of the hardware configuration is omitted here. To do.

The coefficient control unit 19 outputs the output y (n) of the non-recursive unit 18.
The filter coefficient b (n) is updated by the above equation 13 so as to minimize the level.

In the present embodiment, as in the case of the first and second embodiments described above, with respect to the filter coefficient of the cyclic unit 17, the filter coefficient is set so as to minimize the output level of the cyclic unit 17. Since the updates are executed in parallel, it is possible to suppress the divergence of the signal of the patrol unit 17. Further, when the noise is a random sound having no periodicity, the noise signal is not canceled by the patrol unit 17 even if the filter coefficient of the patrol unit 17 is updated so that the output level of the patrol unit 17 is minimized. At this time, the sound emitted from the muffling speaker 15 cancels a part of the signal component fed back to the noise detecting microphone 13, and a further muffling effect can be expected.

FIG. 4 is a block diagram showing a fourth embodiment of the active control apparatus using the adaptive IIR digital filter according to the present invention. The signal u (n) is input to the IIR digital filter 16 and the signal It outputs y (n). IIR
The internal configuration of the digital filter 16 is as follows: the circuit 17 having the filter coefficient b (j) in the front stage and the filter coefficient a in the rear stage.
The acyclic portion 18 having (i) is located. The coefficient control unit 20 updates the filter coefficient a (i),
The output v (n) of the circulation unit 17 and the output error e (n) are input to the coefficient control unit 20. In addition, the coefficient control unit 21 has II
The output y (n) of the R digital filter 16 and the output error e
(n) has been entered. The output error e (n) is the desired response d
It is the difference between (n) and the output y (n) of the IIR digital filter 16. The coefficient control unit 20 updates the filter coefficient a (i) according to the following equation 16 so as to minimize the mean square value of the output error e (n).

[0049]

A (i, n + 1) = a (i, n) + αv (ni) e (n) In the coefficient control unit 21, the filter coefficient b (j) is calculated by the following expression 1
Update according to 1.

[0050]

[Mathematical formula-see original document] b (j, n + 1) = b (j, n) + [beta] y (nj) e (n) Here, [alpha] and [beta] represent step size parameters and take small positive values. In updating the filter coefficient b (j), y ₀ (j, n) of the following _equation 9 can be used instead of y (nj) shown in the equation 11.

[0051]

[Equation 09]

In this embodiment, the updating of the filter coefficient of the non-recursive section 18 can be achieved by updating the coefficient of the FIR digital filter using the output of the cyclic section 17 as an input signal. , Its stability and convergence will be guaranteed. Further, when the filter coefficient is updated using the equations 8 and 9, the operation corresponding to the equation 8 has already been performed in the circulation unit 17, and it is not necessary to calculate again, and the calculation amount is reduced or the circuit scale is reduced. Can be achieved.

FIG. 5 is a block diagram showing the fifth embodiment of the active control apparatus using the adaptive IIR digital filter according to the present invention. The processing of the equation 9 in the embodiment shown in FIG. 4 is the coefficient control. The processing is performed by the unit 21, but the configuration shown in FIG. 5 is provided outside the coefficient control unit 21. The cyclic digital filter 19 in FIG. 5 corresponds to this. Also, in updating the filter coefficient b (j),
The following f which is a moving average of e (n) instead of e (n) of 1
(n) can also be used.

[0054]

[Equation 07]

Here, c (l) represents the weight of the moving average, and L represents the number of data to be averaged.

In this embodiment, as in the case of the above-mentioned fourth embodiment, regarding updating of the filter coefficient of the non-recursive section 18, FIR using the output of the recursive section 17 as an input signal is used.
Since the coefficient updating of the digital filter can be achieved, and the processing of Expression 9 is performed by the digital filter 19, the stability and the convergence of the updating of the filter coefficient of the non-recursive unit 18 are further guaranteed. Further number 8,
When the filter coefficient is updated using the equation 9, the operation corresponding to the equation 8 has already been performed in the circulation unit 17, and it is not necessary to calculate again, and the calculation amount can be reduced or the circuit scale can be reduced. it can.

FIG. 6 is a block diagram showing a sixth embodiment of an active control apparatus using an adaptive IIR digital filter according to the present invention. The noise source 11 is arranged in a container 12 having an opening at one end, and the noise source 11 is arranged in the container 12.
A noise detection microphone 13 and a noise reduction error detection microphone 14 are arranged facing each other, and the noise reduction speaker 1 is provided on the side wall of the container 12.
5 are installed. Detected by the noise detection microphone 13,
The noise signal u (n) converted into a digital signal by the A / D converter 25 via the preamplifier 22 is arithmetically processed by the adaptive IIR digital filter 16, and the arithmetic result is D / A as the mute signal y (n). It is output to the converter 26. D /
The mute signal converted into an analog signal by the A converter 26 is output from the speaker 15 via the power amplifier 23.
The muffling result is detected by the muffling error detection microphone 14,
It is taken into the coefficient control section 20 and the coefficient control section 21 as a muffling error signal -e (n) via the preamplifier 24 and the A / D converter 27. The output v (n) of the circulation unit 17 is also input to the digital filter 32, and the digital filter 32
Output v ₁ (n) is input to the coefficient control unit 20. The output y (n) of the acyclic unit 18 is also input to the digital filter 31, and the output y ₁ (n) of the digital filter 31 is also input to the coefficient control unit 21. Then, the filter coefficients a (i) and b (j) of the adaptive IIR digital filter 16 are updated so that the silencing error signal is minimized. The updating formulas at this time are shown in the following formulas 14 and 11.

[0058]

## EQU14 ## a (i, n + 1) = a (i, n) + αv ₁ (ni) e (n)

[0059]

Equation 11] b (j, n + 1) = b (j, n) + βy 1 (nj) e (n) where alpha, and β denotes a step size parameter and takes a small positive value. When updating the filter coefficient b (j), f (n) in Eq. 7 is replaced with e (n) in Eq.
Can also be used. Further, y ₂ (j, n) of the following formula 12 can be used instead of y ₁ (nj) of the formula 11.

[0060]

[Equation 12]

In this embodiment, as in the case of the above-mentioned fifth embodiment, regarding the update of the filter coefficient of the non-recursive section 18, the FIR using the output of the recursive section 17 as an input signal is used.
Since it is possible to reduce the coefficient update of the digital filter, the stability and convergence of the update of the filter coefficient of the non-recursive unit 18 are guaranteed. Furthermore, the same result can be obtained even if the calculation unit of the equation (25) is placed before the digital filter 21 and the order is changed. Further, when the filter coefficient is updated using the equations 8 and 9, the operation corresponding to the equation 8 has already been performed in the circulation unit 17, and it is not necessary to calculate again, and the calculation amount is reduced or the circuit scale is reduced. Can be achieved.

FIG. 7 is a block diagram showing a seventh embodiment of an active control apparatus using an adaptive IIR digital filter according to the present invention. A noise source 11 is arranged in a container 12 having an opening at one end, and a noise detection microphone 13 and a silencing error detection microphone 14 are arranged in the container 12 so as to face the noise source 11, and the side wall of the container 12 is arranged. Mute speaker 15
Is installed. The noise signal u (n) detected by the noise detection microphone 13 and converted into a digital signal by the A / D converter 25 through the preamplifier 22 is arithmetically processed by the adaptive IIR digital filter 16, and the arithmetic result is a muffling signal. It is output to the D / A converter 26 as y (n). D / A
The mute signal converted into an analog signal by the converter is output from the muffler speaker 15 via the power amplifier 23. The muffling result is detected by the muffling error detection microphone 14, and is taken into the coefficient control section 20 and the coefficient control section 21 as a muffling error signal -e (n) via the preamplifier 24 and the A / D converter 27. The input u (n) of the acyclic unit 18 is input to the digital filter 32, and the output u ₁ (n) of the digital filter 32 is input to the coefficient control unit 20. Circuit 17
The output y (n) of is also input to the digital filter 31,
The output y ₁ (n) of the digital filter 31 is the coefficient control unit 21.
Entered in. Then, the filter coefficients a (i) and b (j) of the adaptive IIR digital filter 16 are updated so that the silencing error signal is minimized. The updating formulas at this time are shown in the following formulas 10 and 11.

[0063]

## EQU10 ## a (i, n + 1) = a (i, n) + αu ₁ (ni) e (n)

[0064]

Equation 11] b (j, n + 1) = b (j, n) + βy 1 (nj) e (n) where alpha, and β denotes a step size parameter and takes a small positive value. In updating the filter coefficient b (j), f (n) in Eq. 7 can be used instead of e (n) in Eq. Also, y in the equation 11
Instead of ₁ (nj), y ₂ (j, n) of the following formula 12 can also be used.

[0065]

[Equation 12]

It should be noted that the same result can be obtained even if the calculation unit of equation (12) is placed before the digital filter 31 and the order is changed. Further, the filter coefficient b of the circulation unit 17
The updating of (j) is also performed from the coefficient control unit 19. The coefficient control unit 19 inputs the output y (n) of the patrol unit 17, and outputs the output y (n).
The filter coefficient b (j) is calculated by the formula 1 so that the level of
Update with 3.

[0067]

B (j, n + 1) = b (j, n) -γy (nj) y (n) where γ is a step size parameter and takes a small positive value. Here, the operation of updating the filter coefficient by Equation 13 controlled by the coefficient control unit 19 is performed by the output signal y of the circulating unit 17.
It is controlled by the power P of (n). That is, the patrol unit 1
The output signal y (n) of 7 is input to the level detection unit 33, and the power P of the output signal y (n) is calculated. Coefficient control unit 19
Performs the filter coefficient updating operation only when the input power P is larger than a predetermined reference power. At this time, the updating of the filter coefficient by the equations 11 and 13 is executed in parallel or in a time-division manner.

In the present embodiment described above, the operation in the coefficient control unit 19 is permitted only when the signal level detected by the level detection unit 33 becomes equal to or higher than a predetermined reference value, so that the signal in the circulation unit 17 is changed. Can be suppressed, and stable update of the filter coefficient can be realized in the adaptive IIR digital filter 16. Furthermore, since the coefficient control unit 19 operates only when the signal level detected by the level detection unit 33 becomes equal to or higher than a predetermined reference value, the circuit unit 17 operates not only for random sounds but also for periodic signals.
Appropriate muffling processing can be performed without being canceled by.

FIG. 8 is a block diagram showing an eighth embodiment of the active control apparatus using the adaptive IIR digital filter according to the present invention. The circuit of the adaptive IIR digital filter 16 shown in FIG. 17 shows a configuration in which 17 and the non-patrol unit 18 are interchanged. At this time, the filter coefficient a (i)
Is updated by the coefficient control unit 20 according to the following equation.

[0070]

A (i, n + 1) = a (i, n) + αv ₁ (ni) e (n) The filter coefficient b (j) is updated by the coefficient control unit 21 according to Expression 11.

[0071]

B (j, n + 1) = b (j, n) + βy ₁ (nj) e (n) Furthermore, the filter coefficient b (j) is the output v (n ) To minimize the level of
Updated by

[0072]

B (j, n + 1) = b (j, n) -γv (nj) v (n) The output signal v (n) of the circulation unit 17 is input to the level detection unit 33, and the output signal v The power P of (n) is calculated. The coefficient control unit 19 that executes Expression 15 performs the filter coefficient updating operation only when the input power P is larger than the predetermined reference power. At this time, the update of the filter coefficient by the equations 11 and 15 is executed in parallel or in a time division manner.

In the above-mentioned embodiment, the operation in the coefficient control section 19 is performed only when the signal level detected by the level detection section 33 becomes equal to or higher than a predetermined reference value, as in the case of the above-mentioned embodiment. By permitting, signal divergence in the circulating unit 17 can be suppressed, and stable filter coefficient updating can be realized in the adaptive IIR digital filter 16. Further, since the coefficient control unit 19 operates only when the signal level detected by the level detection unit 33 becomes equal to or higher than a predetermined reference value, the circuit unit 17 operates not only for random sounds but also for periodic signals. Appropriate muffling processing can be performed without being canceled.

[0074]

As described in detail above, in the active controller using the adaptive IIR digital filter according to the present invention, the means for detecting the amount of physical phenomena before the physical amount is controlled to a desired amount. A signal processing means for inputting the detection means and performing a predetermined signal processing to output a control signal; and a physical phenomenon output means for receiving the control signal and converting the control signal into a physical phenomenon quantity, Having an error output means for outputting an error between the physical phenomenon amount to be performed and the actual physical phenomenon amount,
An active control device using an adaptive IIR digital filter as the signal processing means, wherein a signal from the error output means is input to update a filter coefficient so as to minimize an error level, and the IIR digital filter. And a coefficient control unit for updating the filter coefficient so as to minimize the signal level of the output signal of the cyclic unit of the filter, and the update of the filter coefficient of the cyclic unit is controlled by the coefficient control units of both of them. Since the coefficient control unit performs the filter coefficient update in parallel, the signal divergence in the cyclic unit can be suppressed, and the stable filter coefficient of the adaptive IIR digital filter can be suppressed. Updates can be realized.

Further, the active control device using the adaptive IIR digital filter according to the present invention comprises means for detecting the physical phenomenon amount when controlling the physical phenomenon amount to a desired amount,
A signal processing unit that receives a signal from the detecting unit and performs a predetermined signal processing to output a control signal; and a physical phenomenon output unit that receives the control signal and converts the control signal into a physical phenomenon amount. In an active control device having an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity, and using the adaptive IIR digital filter as the signal processing means, the adaptive digital filter cyclic circuit An output signal of the non-cyclic section, an adaptive control section of the filter coefficient in the cyclic section, which receives the output signal of the non-cyclic section and the error signal output by the error output means, and an output signal of the cyclic section. An adaptive control unit for the filter coefficient in the non-recursive unit, which receives the error signal output by the error output unit as an input, is provided. Since the update of the filter coefficient of the loop part can be reduced to the update of the coefficient of the FIR digital filter using the output of the cyclic part as an input signal, the stability and convergence of the update of the filter coefficient of the non-cyclic part are guaranteed. To be done. Further, in the case of updating the filter coefficient using the equations 8 and 9, the calculation corresponding to the equation 8 in the present configuration has already been performed by the cyclic unit of all stages, and it is not necessary to calculate again and the calculation amount Can be reduced or the circuit scale can be reduced.

Further, the active control device using the adaptive IIR digital filter according to the present invention comprises means for detecting the physical phenomenon amount when controlling the physical phenomenon amount to a desired amount,
A signal processing unit that receives a signal from the detecting unit and performs a predetermined signal processing to output a control signal; and a physical phenomenon output unit that receives the control signal and converts the control signal into a physical phenomenon amount. An active control device having an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity, wherein the signal from the error output means is used in an active controller using an adaptive IIR digital filter as the signal processing means. Is input to update the filter coefficient so as to minimize the error level, and the output signal of the IIR digital filter or the output signal of the circulator is input to minimize the signal level. To detect the level of the output signal of the IIR digital filter or the output signal of the circulator thereof. A bell detection unit, the updating of the filter coefficient of the cyclic unit is controlled by the first and second coefficient control units, and the filter coefficient updating operation by the second coefficient control unit is detected by the level detection unit. The signal level detected by the level detection unit is equal to or higher than a predetermined reference value when the filter coefficient updating operation by the second coefficient control unit is performed according to the determined signal level. By permitting such a case, it is possible to suppress the divergence of the signal in the circulation section, and to realize stable update of the filter coefficient. Further, since the second coefficient control unit operates only when the signal level detected by the level detection unit becomes equal to or higher than a predetermined reference, even the periodic signal is canceled by the circulation unit. Enable proper processing without

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 4 is a configuration diagram showing a fourth embodiment of an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 5 is a configuration diagram showing a fifth embodiment of an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 6 is a configuration diagram showing a sixth embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 7 is a configuration diagram showing a seventh embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 8 is a configuration diagram showing an eighth embodiment of a silencer as an active control device using an adaptive IIR digital filter according to the present invention.

FIG. 9 is a circuit diagram showing a direct type configuration of an IIR digital filter.

FIG. 10 is a circuit diagram showing an active control device using a conventional adaptive IIR digital filter.

FIG. 11 is a schematic block diagram showing a silencer as an active control device using a conventional adaptive IIR digital filter.

FIG. 12 is a circuit diagram showing an active control device using a conventional adaptive IIR digital filter.

[Explanation of symbols]

 16 Adaptive IIR Digital Filter 17 Cyclic Section 18 Non-Cyclic Section 19 Coefficient Control Section 20 Coefficient Control Section 21 Coefficient Control Section 32 Level Detection Section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Hiyoshi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (3)

[Claims] 1. A detection means for detecting the physical phenomenon quantity when controlling the physical phenomenon quantity to a desired quantity, and a signal processing for receiving a signal from the detection means and performing a predetermined signal processing to output a control signal. Means, a physical phenomenon output means for receiving the control signal and converting the control signal into a physical phenomenon quantity, and an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity. An adaptive IIR for the signal processing means
(Infinite Impulse Response) In an active controller using a digital filter, a coefficient control unit for updating a filter coefficient so as to minimize an error level by receiving a signal from the error output means, and an output of the IIR digital filter. A signal or an output signal of the cyclic unit is input, and a coefficient control unit that updates the filter coefficient so as to minimize the signal level is provided, and the update of the filter coefficient of the cyclic unit is performed by both coefficient control units. An active control device using an adaptive IIR digital filter characterized by being configured to be controlled. 2. A means for detecting the physical phenomenon amount when controlling the physical phenomenon amount to a desired amount, and a signal processing for receiving a signal from the detecting means and performing a predetermined signal processing to output a control signal. Means, a physical phenomenon output means for receiving the control signal and converting the control signal into a physical phenomenon quantity, and an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity. An adaptive IIR for the signal processing means
In an active control device using a digital filter, a cyclic section of the adaptive IIR digital filter is connected to a preceding stage of the non-cyclic section, and the output signal of the non-cyclic section and the error signal output by the error output means are input. An adaptive control unit for the filter coefficient in the cyclic unit; and an adaptive control unit for the filter coefficient in the non-cyclic unit that receives the output signal of the cyclic unit and the error signal output by the error output unit as input. An active control device using a characteristic adaptive IIR digital filter. 3. A means for detecting the amount of physical phenomenon when controlling the amount of physical phenomenon to a desired amount, and a signal processing for receiving a signal from the detecting means and performing a predetermined signal processing to output a control signal. Means, a physical phenomenon output means for receiving the control signal and converting the control signal into a physical phenomenon quantity, and an error output means for outputting an error between a desired physical phenomenon quantity and an actual physical phenomenon quantity. An adaptive IIR for the signal processing means
In an active control device using a digital filter, a first coefficient controller for receiving a signal from the error output means to update a filter coefficient so as to minimize an error level, and an output signal of the IIR digital filter, Alternatively, a second coefficient control unit that receives the output signal of the circulation unit and updates the filter coefficient so as to minimize the signal level, and the output signal of the IIR digital filter,
Alternatively, a level detection unit that detects the level of the output signal of the cyclic unit is provided, and updating of the filter coefficient of the cyclic unit is controlled by the first and second coefficient control units, and the second coefficient
2. The active control device using an adaptive IIR digital filter, wherein the filter coefficient updating operation by the coefficient control unit is allowed according to the signal level detected by the level detection unit.