JPH11167383A - Method for checking connection of adaptive equalization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of checking connection of an adaptive equalization system capable of detecting an abnormality of a connection state such as disconnection, etc. SOLUTION: An adaptive equalization system is configured by comprising a switch 2, a loudspeaker 6, a microphone 8, an arithmetic calculation part 12, an adaptive filter 16, an LMS algorithm processing part 14, a steady white noise generation part 18, and a control part 20. only the switch 2 for a channel desired to be checked on the connection state is set to be ON, and steady white noise is radiated from the corresponding loudspeaker 6. The control part 20 judges that this channel is in a normal connection state when a power of an output signal of the microphone collecting sonic reflection of the steady white noise exceeds a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a connection confirmation method for an adaptive equalization system for realizing a desired sound field characteristic in a vehicle cabin. In this specification, capital C, W, H
Represents the vector quantity in lowercase c, e, u, v, x, y, d
Represents a scalar quantity, respectively.

[0002]

2. Description of the Related Art In a closed narrow space such as a vehicle interior, reflection occurs in a short time, and sound waves interfere with each other, so that the transmission characteristic to a listening point becomes very complicated. There is a demand for an audio device for removing such adverse effects in the vehicle interior and improving the acoustic characteristics in the vehicle interior. To meet such demands, an audio device using an adaptive equalization filter has been proposed. A control system has been proposed to obtain desired acoustic characteristics including amplitude and phase characteristics at a plurality of points (control points) in space.

FIG. 7 is a diagram showing a configuration of an adaptive equalization system applied to an audio device. The adaptive equalization system shown in FIG. 1 includes an audio source 100, a target response setting unit 101, a microphone 102, a microphone amplifier 103,
An arithmetic unit 104, an adaptive signal processing device 106, a power amplifier 107, and a speaker 108 are provided.

An audio source 100 is composed of a radio tuner, a CD player, and the like, and outputs an audio signal x (n). The target response setting unit 101 has a target response characteristic (impulse response) H set therein, receives an audio signal x (n) output from the audio source 100, and receives a corresponding target response signal d (n). Is output. The microphone 102 is installed at a listening position (observation point) in the vehicle interior acoustic space, detects a sound at this observation point, and outputs a music signal. The microphone amplifier 103 amplifies the music signal output from the microphone 102 and outputs the amplified music signal d '(n). The arithmetic unit 104 includes the amplified music signal d ′ (n) output from the microphone amplifier 103 and the target response setting unit 1
An error from the target response signal d (n) output from the counter 01 is calculated to output an error signal e (n). Adaptive signal processing device 106 generates signal y (n) such that the power of error signal e (n) is minimized. Power amplifier 107 outputs signal y (n) output from adaptive signal processing device 106.
, And the speaker 108 emits a sound corresponding to the amplified signal y (n) output from the power amplifier 107 to the vehicle interior acoustic space.

The target response characteristic H of the target response setting section 101
Has a characteristic corresponding to the sound field space to be reproduced. For example, assuming that a delay time of about half of the number of taps of the adaptive filter is t, the delay time t has the flat characteristic (gain 1 characteristic) in the entire audio frequency band.
Is set. The delay time t is used by the adaptive filter to accurately approximate the inverse characteristic of the acoustic system, and the target response setting unit 1 having such a target response characteristic.
01 can be realized by setting the tap coefficient corresponding to the delay time t of the FIR (Finite Impulse Response) type digital filter to 1, and setting the other tap coefficients to 0.

The adaptive signal processing device 106 receives the audio signal x (n) as a reference signal, the error signal e (n) output from the arithmetic unit 104, and the error signal e (n). Adaptive signal processing is performed so that the power of n) is minimized, and a signal y (n) is output.
The adaptive signal processing device 106 is an LMS (Least Mean Square).
e) Algorithm processing section 110, adaptive filter 112 having a FIR digital filter configuration, and adaptation by convolving audio signal x (n) with propagation characteristic (transfer characteristic) C of a sound propagation system from speaker 108 to a listening position. Reference signal (filtered reference signal) used for signal processing c
(N).

FIG. 8 is a diagram showing a configuration for identifying an acoustic transmission system used in the signal processing filter 114. As shown in FIG.
The configuration shown in FIG.
Microphone 102, microphone amplifier 103, arithmetic unit 10
4, a power amplifier 107, a speaker 108, a signal processing filter 114, and an LMS algorithm processing unit 116.

In this identification method, the transfer characteristic C 特性 of the sound transfer system C is set by determining the characteristics of the signal processing filter 114 having the same characteristics as those of the sound transfer system C. F
As an adaptive algorithm for determining the characteristics of the IR signal processing filter 114, an LMS algorithm is generally used. According to the LMS algorithm, each tap coefficient vector W of the signal processing filter 114 is updated at each sampling time, and this updating process is repeated until e (n) becomes smaller than a predetermined value.

The LMS algorithm processing section 116 receives the error signal e (n) at the listening position and the stationary white noise signal output from the stationary white noise generating section 200, and uses these signals to generate the error signal e (n).
The tap coefficient vector W of the signal processing filter 114 is set using an LMS adaptive algorithm so that (n) becomes equal to or less than a predetermined value. By such adaptive processing, the tap coefficient vector W of the signal processing filter 114 converges so that the power of the error signal e (n) is minimized, and the transfer characteristic C ＾ of the acoustic transfer system is identified as the tap coefficient vector W. You.

By the way, if the adaptive processing is performed on the entire frequency band of the audio signal as in the above-described adaptive equalization system, the amount of calculation becomes enormous and real-time processing becomes difficult. For example, if you try to process in real time, DSP (Digital Signal Processor)
About several hundred pieces are required. Therefore, an adaptive equalization system has been proposed in which adaptive processing is performed only on low-frequency components, for example, only low-frequency sounds of 200 Hz or lower, thereby lowering the sampling frequency and reducing the load on the DSP.

FIG. 9 is a diagram showing a configuration of an adaptive equalization system that performs an adaptive process only on a bass range. In the adaptive equalization system shown in FIG. 11, a low-pass filter (LPF) 105 for passing low-frequency components is inserted into the input side of the adaptive equalization system shown in FIG. And an audio signal of the entire audible band is input and radiated to the interior of the vehicle.
24 is different from that in which a power amplifier 122 is provided in a stage preceding the speaker 124.

In this adaptive equalization system, only a low-frequency component of an audio signal is separated by a low-pass filter 105, and an audio signal after passing through an adaptive filter 112 and a power amplifier 107 is a speaker 108 as a control sound source.
Output from With the audio signal of the low frequency component, only the low frequency component of the audio signal of the entire frequency band output from the speaker 124 which is the uncontrolled sound source is corrected.

By performing the adaptive processing only on the low frequency component of the audio signal as described above, there are the following advantages. The sampling frequency, that is, the required amount of calculation can be reduced. In a small space such as a vehicle interior, in the low-frequency range, the mode overlap is small and the reflectivity of the wall is high, so that the effect of the standing wave is remarkable. In addition, speakers used for in-vehicle audio devices are limited in size and mounting state, and it is difficult to reproduce sound efficiently in a low-frequency range. For this reason, by concentrating control in the low frequency range, a large control effect can be expected for a small hardware scale.

FIG. 10 is a diagram showing a configuration for identifying an acoustic transfer system used in the signal processing filter 114 of the adaptive equalization system shown in FIG. The configuration shown in the figure is obtained by adding a low-pass filter 105 to the configuration shown in FIG. 8, and determines the characteristics of the signal processing filter 114 having the same characteristics as the sound propagation system C, similarly to the configuration shown in FIG. By doing so, the acoustic transfer system C is identified, and its transfer characteristic C ＾ is set.

In the above-described adaptive equalization system that performs adaptive processing only on the bass range, the speaker 108 as the control sound source and the speaker 124 as the non-control sound source are not necessarily provided one by one. , Respectively.

[0016]

By the way, in the above-described adaptive equalization system that performs adaptive processing only on low-frequency components, an audio signal of a low-frequency component output from a speaker 108 as a control sound source and a non- Unless the audio signal output from the speaker 124 as the control sound source reaches the microphone 102 at the same timing, the entire adaptive equalization system cannot be properly controlled. Therefore, the speaker 108 and the speaker 1
24 (hereinafter collectively referred to as a speaker sound source), it is necessary to measure the delay time of each audio signal. At this time, disconnection and connection failure between the audio source 100 and the speaker sound source occur. If the output is reduced due to the reverse phase connection, accurate measurement of the delay time cannot be performed.
However, since the adaptive equalization system itself cannot recognize a disconnection or the like, the adaptive processing described above is performed assuming that the wrong delay time is correct, and the entire adaptive equalization system can be correctly controlled. Will be gone.

Therefore, in order to correctly measure the delay time and correctly control the entire adaptive equalization system, that is, to realize the target response characteristic H set in the target response setting unit 101 in an arbitrary vehicle interior space or the like. Is the audio source 1
It is necessary to detect an abnormality in the connection state, such as a disconnection between 00 and the speaker sound source.

The present invention has been made in view of the above points, and an object of the present invention is to provide a connection confirmation method of an adaptive equalization system capable of detecting an abnormal connection state such as a disconnection. It is in.

[0019]

In order to solve the above-mentioned problem, in the connection confirmation system of the adaptive equalization system according to the present invention, a confirmation signal is radiated from a speaker via a signal transmission system to be confirmed. Then, the microphone collects sound and determines the connection state of the signal transmission system of interest based on the output signal. If the connection status is normal,
An output signal of a microphone having a power equal to or higher than a predetermined value should be obtained. Conversely, the connection state of the signal transmission system can be easily determined based on the output signal of the microphone. If the connection state of the signal transmission system is normal, the correlation between the input confirmation signal and the output signal of the microphone should be large. Therefore, the connection state of the signal transmission system is determined based on the correlation. be able to.

When an adaptive filter controlled to have characteristics substantially matching the characteristics of the signal transmission system is connected in parallel with the signal transmission system described above, the output signal of the adaptive filter substantially matches the output signal of the microphone. Therefore, the connection state of the signal connection system can be easily determined by using the output signal of the adaptive filter or the tap coefficient of the adaptive filter instead of the output signal of the microphone described above.

Specifically, by setting each tap coefficient so that the power of the error signal between the output signal of the adaptive filter and the output signal of the microphone becomes smaller than a predetermined value, an adaptive signal having the same characteristics as the signal transmission system is obtained. You can set filters.

It is preferable to use a stationary white noise signal as the above-mentioned confirmation signal. By using the stationary white noise signal, the step size setting range of the adaptive processing (for example, processing according to the LMS algorithm) necessary for stably operating the adaptive filter is fixed to a certain range. It will be easier.

When there are a plurality of signal transmission systems,
By connecting switching means to each signal transmission system and selecting one of them, the connection state of a plurality of signal transmission systems can be determined in order.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An adaptive equalization system according to an embodiment of the present invention will be described below with reference to the drawings. In the first to fifth embodiments described below, the switch 2 is a switching unit, the arithmetic unit 12 is an arithmetic unit, the LMS algorithm processing unit 14 is an adaptive processing unit, and the stationary white noise generating unit 18 is a confirmation voice. The control unit 20 corresponds to the supply unit, and corresponds to the connection state determination unit.

(1) First Embodiment FIG. 1 is a diagram showing a configuration of an adaptive equalization system according to a first embodiment to which the present invention is applied. The configuration of the equalization system is shown. As shown in the figure, the adaptive equalization system of the present embodiment includes a switch 2 (2-1 to 2-M), a power amplifier 4 (4-1 to 4-M), and a speaker 6 (6-1 to 6-M). −
M), microphone 8, microphone amplifier 10, arithmetic unit 1
2, LMS algorithm processing unit 14, adaptive filter 1
6. It includes a stationary white noise generator 18 and a controller 20. The number of the speakers 6 is not particularly limited, and it is sufficient that at least one control sound source and one non-control sound source are provided. In addition, there is some configuration such as an adaptive filter other than the power amplifier 4 in the stage preceding the speaker 6 which is a control sound source. In this case, a switch (not shown) that bypasses this configuration is provided. With this switch, it is not necessary to treat each speaker 6 as a control sound source and a non-control sound source separately.

The switch 2 includes a white noise generator 18
Is a switch for guiding the white noise signal u (n) as a confirmation signal output from the corresponding speaker 6 to the corresponding speaker 6, and only the switch 2 corresponding to one speaker 6 whose connection state is desired to be confirmed is closed. The power amplifier 4
The stationary white noise signal u (n) is amplified, and the amplified stationary white noise is radiated from the speaker 6.

The microphone 8 collects a steady white noise signal u (n) radiated from the speaker 6 and outputs it to the microphone amplifier 10. The microphone amplifier 10 amplifies the signal and amplifies the microphone output signal v _m (n). ) Is output. The calculation unit 12 outputs the microphone output signal v _m (n) and the adaptive filter output signal v _w output from the adaptive filter 16.
An error with respect to (n) is calculated and an error signal e (n) is output.

The LMS algorithm processing unit 14 receives the error signal e (n) and the stationary white noise signal u (n), and uses these signals to minimize the error signal e (n). , The tap coefficient vector W of the adaptive filter 16 is set using the LMS adaptive algorithm. The adaptive filter 16 uses the tap coefficient vector W set in this way to generate a stationary white noise signal u (n).
And outputs an adaptive filter output signal v _w (n). The control unit 20 controls the alternative switching of the switch 2 and the microphone output signal v
_The connection state is determined by calculating the average value of _m (n).

A connection system to each speaker 6 in the present embodiment (hereinafter, a signal transmission system up to each speaker 6-i whose connection is to be checked will be described as "channel (i)". Confirmation of the connection state of ()) is performed in the following procedure.

First, the control unit 20 operates the switch 2 corresponding to any channel (i) whose connection state is to be checked.
-I is turned on. Thus, the stationary white noise signal u output from the stationary white noise generator 18
(N) is a power amplifier 4-i via a switch 2-i.
And is radiated from the speaker 6-i into the vehicle interior. The steady white noise signal u (n) radiated into the vehicle interior reaches the microphone 8 via an acoustic transmission system (acoustic space) in the vehicle interior, is collected, further amplified by the microphone amplifier 10, and is amplified. Output signal v _m
(N) is output.

The control unit 20 fetches N microphone output signals v _m (n) and calculates an average value E [v _m ² (n)] according to the following equation (1).

[0032]

(Equation 1)

Next, if the obtained average value E [v _m ² (n)] is equal to or larger than a predetermined value, the control unit 20 sets a channel (stationary) between the stationary white noise generation unit 18 and the speaker 6-i. It is determined that the connection state of i) is normal, and if it is less than a predetermined value, it is determined that the connection state is not normal.

(2) Second Embodiment FIG. 2 is a diagram showing a configuration of an adaptive equalization system according to a second embodiment. The adaptive equalization system according to the second embodiment performs connection confirmation based on an output of an adaptive filter. The configuration is shown. As shown in the figure, the adaptive equalization system according to the present embodiment is configured such that the adaptive filter output signal v _w (n) is input to the control unit 20 instead of the microphone output signal v _m (n). Has the same configuration as the adaptive equalization system of the first embodiment shown in FIG.

By the way, the state where the error signal e (n) of the adaptive equalization system shown in FIG. 2 becomes smaller than a predetermined value and the value of each tap coefficient vector W of the adaptive filter 16 converges, This corresponds to the fact that the characteristics almost match the acoustic characteristics of the channel of interest. Therefore, if, for example, a signal line break occurs in the channel of interest and a steady white noise signal is not output from the corresponding speaker 6, each tap coefficient vector W that reproduces this state is output to the adaptive filter 1.
6 is set. Therefore, the adaptive filter output signal v _w
(N) becomes equal to the microphone output signal v _m (n). In the present embodiment, utilizing this fact, the connection state is confirmed based on whether or not the average value of the adaptive filter output signal v _w (n) has reached a predetermined value or more.

The connection state of each channel in this embodiment is confirmed in the following procedure.

First, the control unit 20 operates the switch 2 corresponding to any channel (i) whose connection state is to be checked.
-I is turned on. Thus, the stationary white noise signal u output from the stationary white noise generator 18
(N) is a power amplifier 4-i via a switch 2-i.
And is radiated from the speaker 6-i into the vehicle interior. The stationary white noise signal u (n) radiated into the vehicle interior reaches the microphone 8 via the acoustic transmission system in the vehicle interior, is collected, and is amplified by the microphone amplifier 10. The operation unit 12 includes a microphone output signal v _m (n) output from the microphone amplifier 10 and an adaptive filter output signal v _w (n) output from the adaptive filter 16.
And outputs an error signal e (n). LM
The S-algorithm processing unit 14 receives the error signal e (n) and the stationary white noise signal u (n) output from the stationary white noise generating unit 18, and uses these signals to generate the error signal e (n). ) Is minimized using the LMS adaptive algorithm so that the power of the adaptive filter 16 is minimized.
Is set. Adaptive filter 16
Performs a digital filter process on the stationary white noise signal u (n) using the tap coefficient vector W thus set, and outputs an adaptive filter output signal v _w (n).

Next, the control unit 20 controls the adaptive filter 16
, And fetches N adaptive filter output signals v _w (n), and calculates an average value E [v _w ² (n)] according to the following equation (2).

[0039]

(Equation 2)

If the calculated average value E [v _w ² (n)] is equal to or greater than a predetermined value, the control unit 20 determines whether the channel (i) between the stationary white noise generating unit 18 and the speaker 6-i. It is determined that the connection in ()) is normal, and if it is less than the predetermined value, it is determined that the connection state is not normal.

(3) Third Embodiment In the second embodiment, the connection state of each channel is confirmed based on the output signal of the adaptive filter, but the connection is confirmed based on the filter coefficient of the adaptive filter 16. You may.

FIG. 3 is a diagram showing the configuration of the adaptive equalization system according to the third embodiment. The configuration of the adaptive equalization system when connection is confirmed based on the filter coefficients (tap coefficients) of the adaptive filter 16 is shown. It is shown. As shown in the figure, the adaptive equalization system of the present embodiment is different from the adaptive filter system in that each tap coefficient a0 to an of the adaptive filter 16 is taken into the control unit 20 instead of the adaptive filter output signal v _w (n). Has the same configuration as the adaptive equalization system of the second embodiment shown in FIG.

FIG. 4 is a diagram showing a detailed configuration of the adaptive filter 16. As shown in the figure, the adaptive filter 16 included in the adaptive equalization system of the present embodiment has a tap number n +
1 is an FIR type control filter, which sequentially converts input signals into 1
N delay elements DL1 to DL that delay sampling time
n, n + 1 multiplying units ML0 to MLn for multiplying each delayed output by each tap coefficient a0 to an, and an adding unit AD for adding each multiplied output. This adaptive filter 16
Tap coefficients a0 of the multiplication units ML0 to MLn included in
~ An is taken into the control unit 20.

The confirmation of the connection state of each channel in this embodiment is performed in the following procedure.

First, the control unit 20 operates the switch 2 corresponding to any channel (i) whose connection state is to be checked.
-I is turned on, and the stationary white noise generator 18 is turned on.
Is amplified by the power amplifier 4-i and emitted from the speaker 6-i into the vehicle interior. The arithmetic unit 12 includes a microphone output signal v _m (n) output from the microphone amplifier 10 and an adaptive filter output signal v output from the adaptive filter 16.
_The LMS algorithm processing unit 14 calculates an error from _w (n) and outputs an error signal e (n).
The tap coefficient vector W of the adaptive filter 16 is set using the LMS adaptive algorithm so that the power of (n) is minimized.

The control unit 20 fetches the tap coefficients a0 to an of the tap coefficient vector W set as described above, and calculates the norm N (W) of the adaptive filter 16 according to the following equation (3). I do.

[0047]

(Equation 3)

Next, if the calculated value of the norm N (W) is equal to or greater than a predetermined value, the control unit 20 connects the channel (i) between the stationary white noise generating unit 18 and the speaker 6-i. Is determined to be normal, and if less than the predetermined value, it is determined that the connection state is not normal.

(4) Fourth Embodiment FIG. 5 is a diagram showing the configuration of an adaptive equalization system according to a fourth embodiment. The cross-correlation function between an input stationary white noise signal and a microphone output signal is shown in FIG. 1 shows a configuration of an adaptive equalization system in a case where connection is confirmed based on the above.
As shown in the figure, the configuration of the adaptive equalization system of the present embodiment has basically the same configuration as the adaptive equalization system shown in FIG. The difference is that a white noise signal is captured.

By the way, the microphone output signal v
_m (n) amplifies the stationary white noise signal u (n)
Since these are collected, there is a correlation between these signals. Therefore, if the steady white noise generator 18 and the speaker 6 are correctly connected, the correlation becomes higher, and if a disconnection or the like occurs, the correlation becomes lower. What indicates such a degree of correlation is a cross-correlation function.
In the present embodiment, a cross-correlation function between the steady white noise output signal u (n) and the microphone output signal v _m (n) is calculated, and the connection state of each channel is checked according to the magnitude of this value. Things.

The connection state of each channel in this embodiment is confirmed in the following procedure.

First, as in the first embodiment shown in FIG. 1, the control unit 20 turns on the switch 2-i corresponding to any channel (i) whose connection state is to be checked. As a result, the steady white noise signal u (n) output from the steady white noise generator 18 is amplified by the power amplifier 4-i and then released from the speaker 6-i into the vehicle interior, and the microphone output signal from the microphone amplifier 10 is output. v _m (n) is output.

Next, the control unit 20 controls the stationary white noise signal u (n) and the microphone output signal v
_m (n), and according to the following equation (4),
The cross-correlation function φa (l) of these two signals is calculated.

[0054]

(Equation 4)

If the value of the calculated cross-correlation function φa (l) is equal to or larger than a predetermined value, the control unit 20 sets the channel (i) between the stationary white noise generating unit 18 and the speaker 6-i. It is determined that the connection is normal, and if less than a predetermined value, it is determined that the connection state is not normal.

(5) Fifth Embodiment In the above-described fourth embodiment, the connection state is confirmed based on the cross-correlation function between the input stationary white noise signal and the microphone output. As described in the embodiment, the state in which the error signal e (n) becomes equal to or less than the predetermined value and the value of each tap coefficient vector W of the adaptive filter 16 converges means that the channel of the characteristic of the adaptive filter 16 is focused on. , The adaptive filter output signal v _w (n) becomes equal to the microphone output signal v _m (n). Therefore, when calculating the value of the cross-correlation function described above, the adaptive filter output signal v is used instead of the microphone output v _m (n).
_w (n) may be used.

FIG. 6 is a diagram showing the configuration of the adaptive equalization system according to the fifth embodiment. The adaptive equalization system in the case where connection is confirmed based on a cross-correlation function between stationary white noise and the output of an adaptive filter. FIG. 3 is a diagram showing the configuration of FIG. As shown in the figure, the adaptive equalization system of the present embodiment has basically the same configuration as the adaptive system of the second embodiment shown in FIG.

The connection state of each channel in this embodiment is confirmed by the following procedure.

First, as in the second embodiment shown in FIG. 2, the control unit 20 turns on the switch 2-i corresponding to any channel (i) whose connection state is to be checked. As a result, the steady white noise signal u (n) output from the steady white noise generator 18 is amplified by the power amplifier 4-i and then released from the speaker 6-i into the vehicle interior, and the microphone output signal from the microphone amplifier 10 is output. v _m (n) is output, and the adaptive filter 16 outputs an adaptive filter output signal v _w (n) equal to the microphone output signal v _m (n).

Next, the control unit 20 controls the stationary white noise signal u (n) and the adaptive filter output signal v
_w (n), and according to the following equation (5),
The cross-correlation function φb (l) of these two signals is calculated.

[0061]

(Equation 5)

If the calculated value of the cross-correlation function φb (l) is equal to or greater than a predetermined value, the control unit 20 sets the channel (i) between the stationary white noise generation unit 18 and the speaker 6-i. It is determined that the connection is normal, and if less than a predetermined value, it is determined that the connection state is not normal.

As described above, in the adaptive equalization systems of the above-described various embodiments, the control unit 20 switches the switch 2 corresponding to the channel whose connection is to be confirmed to the ON state, and the speaker 6 corresponding to this switches the normal state. A white noise signal is output. In this state, 1) the microphone output signal v _m (n) and the adaptive filter output signal v
the average value of _w (n), 2) its norm N (W) from the tap coefficients a0 to an of the adaptive filter 16, 3) the steady white noise signal u (n) input and the microphone output signal v _m (n) or The control unit 20 calculates one of the cross-correlation functions φa (l) and φb (l) with the adaptive filter output signal v _w (n), and if the calculation result is equal to or greater than a predetermined value, the connection state of the channel Is normal, and it is determined that there is no connection abnormality such as disconnection, connection failure, or reverse-phase connection. On the other hand, if the above calculation result is less than the predetermined value, it is determined that the connection state of the channel is not normal and that a connection abnormality such as disconnection, connection failure, or reverse phase connection has occurred in this channel.

Therefore, the control unit 20 can check the connection state of each channel, and can measure an erroneous delay time of a signal transmitted through each channel without knowing that there is a connection error. Can be eliminated. Thereby, the timing (phase) when the audio signal radiated from each speaker 6 reaches the microphone 8 can be adjusted, and the adaptive equalization system can be appropriately controlled.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in each of the above-described embodiments, a steady white noise signal is used as the confirmation signal. However, since it is sufficient that the connection state of each channel can be confirmed, particularly a steady white noise signal is used for a signal that is constantly outputted. The signal is not limited to the noise signal, and another signal may be used.

[0066]

As described above, according to the present invention, when a confirmation signal is radiated from a speaker via a signal transmission system to be connected and confirmed, sound is collected by a microphone, and the sound is collected according to the output signal. Since the connection state of the signal transmission system is determined, it is easy to determine whether the connection state is normal.
If the connection state of the signal transmission system is normal, the correlation between the input confirmation signal and the output signal of the microphone should be large. Therefore, the connection state of the signal transmission system is determined based on the correlation. You can also.

When an adaptive filter is connected in parallel with the above-described signal transmission system and is controlled to have characteristics substantially matching the characteristics of the signal transmission system, the output signal of the adaptive filter substantially matches the output signal of the microphone. Therefore, it is easy to determine whether the connection state of the signal connection system is normal using the output signal of the adaptive filter or the tap coefficient of the adaptive filter instead of the output signal of the microphone described above. can do.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an adaptive equalization system according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration of an adaptive equalization system according to a second embodiment.

FIG. 3 is a diagram illustrating a configuration of an adaptive equalization system according to a third embodiment.

FIG. 4 is a diagram showing a detailed configuration of an adaptive filter.

FIG. 5 is a diagram illustrating a configuration of an adaptive equalization system according to a fourth embodiment.

FIG. 6 is a diagram illustrating a configuration of an adaptive equalization system according to a fifth embodiment.

FIG. 7 is a diagram showing a configuration of a conventional adaptive equalization system.

8 is a diagram showing a configuration for identifying an acoustic transmission system used in a signal processing filter of the adaptive equalization system of FIG. 7;

FIG. 9 is a diagram illustrating a configuration of an adaptive equalization system that performs adaptive processing on a bass range.

10 is a diagram showing a configuration for identifying an acoustic transmission system used in a signal processing filter of the adaptive equalization system shown in FIG. 9;

[Explanation of symbols]

 2 Switch 4 Power amplifier 6 Speaker 8 Microphone 10 Microphone amplifier 12 Operation unit 16 Adaptive filter 14 LMS algorithm processing unit 20 Control unit

Claims (8)

[Claims] 1. A speaker connected to a signal transmission system to be connected and a confirmation audio supply unit for emitting a predetermined audio from the speaker by inputting a predetermined confirmation signal to the signal transmission system. Adaptive equalization, comprising: a microphone set at a position separated from the speaker; and connection state determination means for determining a connection state of the signal transmission system based on an output signal of the microphone. System connection confirmation method. 2. A loudspeaker connected to a signal transmission system for which connection is to be confirmed, and a confirmation sound supply means for emitting a predetermined sound from the speaker by inputting a predetermined confirmation signal to the signal transmission system. And a microphone set at a position separated from the speaker, based on a correlation between the confirmation signal input by the confirmation sound supply unit and an output signal of the microphone,
And a connection state determining means for determining a connection state of the signal transmission system. 3. A speaker connected to a signal transmission system for which connection is to be confirmed, and a confirmation sound supply means for emitting a predetermined sound from the speaker by inputting a predetermined confirmation signal to the signal transmission system. A microphone installed at a position separated from the speaker; an adaptive filter connected in parallel to the signal transmission system and controlled to have characteristics substantially matching the characteristics of the signal transmission system; and an output signal of the adaptive filter. And a connection state determining means for determining a connection state of the signal transmission system based on the connection verification method of the adaptive equalization system. 4. A speaker connected to a signal transmission system for which connection is to be confirmed, and a confirmation sound supply means for emitting a predetermined sound from the speaker by inputting a predetermined confirmation signal to the signal transmission system. A microphone installed at a position separated from the speaker; an adaptive filter connected in parallel to the signal transmission system and controlled to have characteristics substantially matching the characteristics of the signal transmission system; tap coefficients of the adaptive filter And a connection state determining means for determining a connection state of the signal transmission system based on the value of the signal transmission system. 5. A speaker connected to a signal transmission system for which connection is to be confirmed, and a confirmation sound supply means for emitting a predetermined sound from the speaker by inputting a predetermined confirmation signal to the signal transmission system. A microphone installed at a position separated from the speaker; an adaptive filter connected in parallel to the signal transmission system and controlled to have characteristics substantially matching the characteristics of the signal transmission system; and Based on the correlation between the input confirmation signal and the output signal of the adaptive filter,
And a connection state determining means for determining a connection state of the signal transmission system. 6. The arithmetic unit according to claim 3, wherein a difference between an output signal of the adaptive filter and an output signal of the microphone is obtained to output an error signal, and an error output from the arithmetic unit. An adaptive processing means for setting a tap coefficient of the adaptive filter so that a signal power becomes smaller than a predetermined value; and a connection confirmation method for an adaptive equalization system. 7. The connection confirmation method for an adaptive equalization system according to claim 1, wherein a steady white noise signal is used as the confirmation sound signal. 8. The signal processing system according to claim 1, further comprising a plurality of switching units connected to each of the signal transmission systems when there are a plurality of the signal transmission systems. A connection confirmation method for an adaptive equalization system, wherein a connection state of a corresponding signal transmission system is determined by selectively selecting the connection state.