JPH08211116A - Transfer characteristics measuring apparatus, echo canceler and loudspeaker employing it - Google Patents

Abstract

PURPOSE: To measure the transfer characteristics of a measuring object transfer system by using a measuring signal having only the frequency components on the outside of a specific frequency band except when the apparatus is installed or adjusted. CONSTITUTION: A measuring signal generating section 3 generates a measuring signal S1 not having a specific frequency band Δf1 but having a nonspecific frequency band Δf2 and the measuring signal S1 is delivered to a measuring object transfer system 1. A measuring signal S2 where the transfer characteristics of the transfer system 1 is convoluted to the measuring signal S1 is taken out from an output terminal 1b. It is then separated, at a signal separating section 5, into a signal S4 (Δf1 ) in the specific frequency band Δf1 and a signal S3 (Δf2 ) in the nonspecific frequency band Δf2 . Based on a separated signal S2 (Δf2 ) and the measuring signal S1 , a transfer characteristics predicting calculating section 4 calculates a transfer characteristic function hf1 (t) in the specific frequency band 9f1 of the transfer system 1 and the Fourier transform Tf1 (W) thereof, as required, thus obtaining the results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer characteristic measuring apparatus used for measuring indoor acoustic characteristics, line transmission characteristics and the like, and an echo suppressor and a loudspeaker using the transfer characteristic measuring apparatus.

[0002]

2. Description of the Related Art Conventionally, as a method of measuring a transfer characteristic of a signal transfer system, random noise, impulse, chirp signal, voice or the like having a frequency component within a specific frequency band Δf ₁ has been used as a measurement signal to measure a specific frequency. There has been a method of measuring the transfer characteristic within the band Δf ₁ . FIG. 10 is a diagram illustrating a conventional device that measures a transfer characteristic using a measurement signal having only frequency components within a specific frequency band Δf ₁ .
Is a measured (signal) transfer system, 1a and 1b are signal input terminals and output terminals thereof, 2 is a transfer characteristic measuring device, 2
Reference numerals a and 2b are signal input terminals and output terminals thereof, 3 is a measurement signal generating section having a specific frequency band Δf ₁ , and 4 ′ is a transfer characteristic measuring section of the specific frequency band Δf ₁ . In order to operate the conventional transfer characteristic measuring device 2, the measurement signal S ₁ generated in the measurement signal generator 3 in the specific frequency band Δf ₁ is used.
(Δf ₁ ) is input to the signal input terminal 1a of the transmission system 1 to be measured. The measurement signal S measured train output signal S ₂ which transfer characteristic is convolved 1 to ₁ taken out from the output terminal 1b, since further measurement signal S ₁ and (Delta] f _1), the transfer characteristic measurement unit 4 ' The transfer characteristic function h _f1 (t) of the specific frequency band Δf ₁ and, if necessary, T _f1 (ω) are calculated.
T _f1 (ω) is a frequency function obtained by Fourier transforming h _f1 (t).

However, with this method, a specific frequency is being measured during measurement.
Band Δf₁Is the measurement signal S₁, S₂Occupied by
Therefore, during measurement, the specific frequency band Δf₁Is an eye other than measurement
There was a disadvantage that it was not available. In addition, the specific frequency band Δ
f₁Can be measured when the is being used for purposes other than measurement.
There were no drawbacks. For example, radiate from a loudspeaker speaker
By the sound that is returned to the microphone through the space
Previously used as an echo canceller to eliminate the generated echo
Although the technology is applied, in the echo canceller,
Above all, it is necessary to measure transfer characteristics due to sound field fluctuation (here
And call signal band is specified frequency band Δf₁And then speedy
The bandwidth of the acoustic system of the microphone or microphone is Δf₁All around
Wavenumber band Δf_FourAnd). Traditionally, echo cancellers
The sound field fluctuation is learned and adapted by the received voice signal during a call.
It has come. However, in this method, the transmission signal and the reception signal are
Is a specific frequency band Δf ₁Double talk that exists at the same time in
In some cases, learning is done during double talk, because it sometimes learns incorrectly.
There was a problem that I could not do.

[0004]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a system to be measured even if the transmission system to be measured is being used for purposes other than measurement and a signal in a specific frequency band Δf ₁ is flowing. It is intended to make it possible to measure the transfer characteristic of the transfer system to be measured without giving interference. A second object is to apply the transfer characteristic measuring apparatus of the first object to an echo canceller and a loudspeaker so as to improve their characteristics.

[0005]

Means for Solving the Problems To achieve the above object,
Therefore, the transfer characteristic measuring device of the present invention is
₁Outside non-specific frequency band Δf₂For measurement with only components
Signal S₁(Δf₂) Is used to specify a specific frequency band Δf₁of
The most important feature is to measure transfer characteristics. Conventional
Is a specific frequency band Δf₁Outside non-specific frequency Δ
f₂Signal S with only components₁(Δf₂) For measuring signal
The difference is that it is used as.

[0006]

Even during [create a measurement, because of the use of a specific frequency band Delta] f ₁ outside the measurement signals S ₁ having only non-specific frequency band Delta] f ₂ component (Delta] f ₂₎ as the measurement signal, the specific frequency band Delta] f ₁ The measurement signal S ₁ (Δf ₂ ) is not mixed in the signal, the specific frequency band Δf ₁ can be used for purposes other than the measurement, and the signal of Δf ₁ can be applied to the transmission system. Therefore, measurement is possible even when the specific frequency band Δf ₁ is used for purposes other than measurement.

[0007]

FIG. 1 is a diagram for explaining an embodiment of the invention of claim 1.
Therefore, the parts corresponding to those in FIG.
It 1 is the measurement object (signal) transmission with the transmission frequency band F
System, 1a is its signal input terminal, 1b is its output terminal, 2
a is a signal input terminal of the transfer characteristic measuring device 2 and 2b is its output terminal.
Force terminal, 3 is a non-specific frequency band Δf₂Measuring signal with
Raw part, 4 is a specific frequency band Δf₁Of transmission characteristics in
The measurement calculation unit 5 is a signal separation unit. In addition, F⊇Δf₁+
Δf₂Is. Operates the transfer characteristic measuring device 2 of the present invention
Is a specific frequency band Δf in the measurement signal generator 3.₁
Non-specific frequency band Δf that does not include₂Measurement signal S with
₁Is generated and input to the measurement target transfer system 1. Measurement signal
No. S₁The transfer characteristics of the transmission system 1 to be measured are folded into
Measurement signal S₂Output from the output terminal 1b to separate the signals
Part 5 specific frequency band Δf ₁Signal S_Four(Δ
f₁) And non-specific frequency band Δf₂Signal S₃(Δf₂)
To separate. Separated signal S₃(Δf₂) And measuring signal
No. S₁(Δf₂) And in the transfer characteristic prediction calculation unit 4
Specific frequency band Δf of the transmission system 1 to be measured₁Transmission in
Characteristic function h_f1(T) and its Fourier transform T if necessary
_f1Calculate (ω) and get the result.

FIG. 2 is a block diagram when the transfer characteristic measuring device 2 of FIG. 1 is incorporated in an echo canceller, and parts corresponding to those of FIG. 1 are designated by the same reference numerals. Reference numeral 11 is an input terminal of the received voice signal R (Δf ₁ ), 12 is an adder, and 13
Is a speaker amplifier, 14 is a speaker, 15 is a transfer characteristic simulation unit of a specific frequency band Δf ₁ , and 16 is a transmitted voice signal S.
An output terminal of (Δf ₁ ), 17 is a subtractor, 18 is a microphone amplifier, and 19 is a microphone.

The echo canceller is a device for eliminating an echo generated when a sound emitted from a speaker passes through a space and enters a microphone. The principle of this echo canceller is that the transfer characteristic function h _f1 (t) of the specific frequency band Δf ₁ measured by the transfer characteristic measuring device 2 and, if necessary, T _f1
Using (ω), the transfer characteristic simulating unit 15 uses the specific frequency band Δ
The transmission system ₁ of f ₁ to be measured is simulated, and the subtractor 17 subtracts the signal r generated by the simulation unit 15 and the echo coming from the microphone 19 to eliminate the echo.

The operation will be briefly described with reference to the input terminal 11.
Received voice signal R (Δf ₁) To the adder 12
In addition, the measurement signal S generated by the measurement signal generator 3₁
(Δf₂) Is added and output from the speaker 14.
Signal S input from microphone 19₂(Δf₁, Δf₂)
Is a specific frequency band Δf in the signal separation unit 5.₁Signal S_Four(Δ
f₁) And non-specific frequency band Δf₂Signal S₃(Δf₂)
Is separated into The signal S output from the signal separation unit 5
₃(Δf₂) Is input to the transfer characteristic prediction calculation unit 4 and specified.
Frequency band Δf₁Transfer characteristic function h at_f1(T) and
T as required_f1(Δf₁) Is calculated. Calculated transmission
Characteristic h_f1And T if necessary_f1Enters the transfer characteristic simulation unit 15
Characteristics of acoustic system composed of speaker and microphone
Used to simulate. On the other hand, the signal separating unit 5 outputs
Forced signal S_Four(Δf₁) Is input to the subtractor 17.
And the specific frequency band output from the transfer characteristic simulation unit 15
Δf₁Received voice signal r (Δf₁) Is subtracted.
The output of the subtractor 17 is the transmitted voice signal S (Δf₁) As
It is output from the output terminal 16.

FIG. 3 shows the echo canceller 100 of FIG.
When howling suppression is used by using a loudspeaker (PA)
2 is a diagram for explaining the above, and the same reference numerals are given to the portions corresponding to those in FIG.
No., and duplicate description is omitted. 21 is an amplifier, 21
Reference numerals a and 21b are input terminals and output terminals thereof. echo
The input / output terminals 11 and 16 of the canceller are respectively connected to the amplifier.
It is connected to the output terminal 21b and the input terminal 21a. My
Voice signal S input from₂(Δf₁, Δf₂) Is
The signal S (Δf is processed by the co-canceler 100. ₁)But
It is input to the amplifier 21. Amplified signal R (Δf₁)
Is input to the input terminal 11 of the echo canceller,
The voice signal is output from the speaker 14.

In the echo canceller incorporating the conventional transfer characteristic measuring device, the transfer characteristic cannot be measured during the double talk in which the transmission signal and the reception signal are simultaneously flowing, and the echo cancellation amount is small. Moreover, it cannot be used for howling suppression of a loudspeaker (PA) in which a transmitted voice and a received voice are always present at the same time. However, in the case of the echo canceller of FIG. 2 in which the transfer characteristic measuring device of the present invention is incorporated, since the transmitting and receiving signals and the measurement signal use different frequency bands, the transfer characteristic can be measured even during double talk. Therefore, the amount of echo cancellation can be increased, and it can also be used for suppressing howling of the loudspeaker (PA) as shown in FIG.

FIG. 4 is a diagram for explaining an embodiment of the invention of claim 2, parts corresponding to those in FIG. Reference numeral 4a denotes a delay time / amplitude change parameter extraction unit 4b. In FIG. 4, the operation is the same as that in FIG. 1 except that the transfer characteristic prediction calculation unit 4 is composed of a delay time / amplitude change parameter extraction unit 4a and a transfer characteristic calculation unit 4b. In this case, in the delay time / amplitude change parameter extraction unit 4a, n impulse response sequences (Δf ₂ = Δf) of the filter that cut off the transfer characteristic h _f2 (t) of the non-specific frequency band Δf ₂ from the specific frequency band Δf _{1 3-} Δf ₁
Therefore, using the impulse response sequence of the filter that passes only the non-specific frequency band Δf ₂ ) (1)
Model as an expression.

H _f2 (t) = Σa _n δ _f2 (t−d _n ) ... (1) In the formula (1), a _n is a parameter representing the amplitude change,
d _n is a parameter representing a delay time, t is time, δ _f2 is an impulse response of a filter that cuts off a specific frequency band Δf ₁ , and Σ is a sum for the order n. The signal S ₃ (Δf ₂ ) of the non-specific frequency band Δf ₂ that has passed through the measurement target transmission system 1 separated by the signal separation unit 5 and the measurement signal of the non-specific frequency band Δf ₂ generated by the measurement signal generation unit 3. From the peak amplitude value of the cross-correlation function of S ₁ (Δf ₂ ) a
The _n, and estimates the d _n from the peak position on the time axis. Such modeling is effective when the signal transmission system is composed of a combination of simple delay and amplitude change.

For example, in a loudspeaker system, a signal is input to a speaker on one side of a room where the reflection characteristics of a wall are flat with respect to frequency, and the sound picked up by a microphone is output on the other side to measure the transfer characteristics of the room. In this case, most of the sound picked up by the microphone is a collection of echoes from the wall, that is, the transfer characteristics can be modeled by a collection of sounds radiated from the speaker with only delay and amplitude changes. it is conceivable that. The same applies when measuring the line echo of a telephone line or the like.

Next, the transfer characteristic calculation unit 4b specifies
Frequency band Δf₁Transfer characteristic function h of _f1(T) is a specific frequency
Several bands Δf₁N impellers of a filter that pass only
Modeling is performed as in equation (2) using the loose response sequence. h_f1(T) = Σa_nδ_f1(T-d_n) (2) In equation (2), Σ is the sum for the order n, and δ
_f1Is a specific frequency band Δf₁Of a filter that only passes
Is the impulse response, δ_f1= Δ_f3−δ_f2Is. here
And δ_f3Is the frequency band Δf₃A filter that passes only
Is the impulse response of Δf₃= Δf₁+ Δf₂And
It It is estimated by the delay time and amplitude change parameter extraction unit 4a.
Specified a_n, D_nTo a specific circumference of the signal transmission system 1 to be measured
Wavenumber band Δf₁Transfer characteristic function h of_f1(T) is calculated and the result
Get.

FIG. 5 is a diagram for explaining an echo canceller incorporating the transfer characteristic measuring device of FIG. 4, in which parts corresponding to those of FIGS. 1 to 5 are designated by the same reference numerals. 5, the operation is the same as that of FIG. 2 except that the transfer characteristic prediction calculation unit 4 is composed of the delay time / amplitude change parameter extraction unit 4a and the transfer characteristic calculation unit 4b of the specific frequency band Δf ₁ .

FIG. 6 is a diagram for explaining howling is suppressed by using the echo canceller 100 of FIG. 5 in a loudspeaker (PA), and the same reference numerals as before are used. In FIG. 6, the transfer characteristic prediction / calculation unit 4 includes a delay time / amplitude change parameter extraction unit 4a and a specific frequency band Δ
The operation is the same as that of FIG. 3 except that the transfer characteristic calculation unit 4b for f ₁ is used.

In the embodiment of FIG. 4, the reflection characteristic of the wall of the room is flat with respect to the frequency, but in general, the reflection characteristic of the wall often has a frequency characteristic. Therefore, when the device is installed and adjusted, the entire frequency band Δf ₄ (however, F
A case will be described in which the transmission characteristic of ⊇Δf ₄ ⊇Δf ₁ + Δf ₂ ) is measured and the reflection characteristic is corrected. FIG. 7 is a diagram for explaining an embodiment of the invention of claim 3, parts corresponding to those in FIGS. 25 switch, a filter for cutting off a specific frequency band Delta] f ₁ is 26 (BEF), 28 is a memory which stores the initial transmission characteristic data in the entire frequency band Delta] f _4, 29 initial transfer property measurement of the total frequency band Delta] f ₄ It is a department.

In FIG. 7, the measurement signal generator 3 includes a total frequency band (Δf ₄ ) signal generator 3a, a BEF 3b that cuts off a specific frequency band Δf ₁ , and a BE when adjusting the equipment.
It is composed of a switching unit 3c that bypasses F3b, and the entire frequency band measurement signal S ₁ (Δf ₄ ) in which the BEF 3b is bypassed by the switching unit 3c during device installation adjustment and the measurement signal are input to the measurement target signal transmission system 1. Output signal S ₂
Initial transfer characteristics in the entire frequency band Delta] f ₄ from the (h _f1
(T) and h _f2 (t) (including each parameter) are calculated, and the calculated initial transfer characteristic data of the entire frequency band Δf ₄ are stored in the transfer characteristic calculating section 4b. The operation is the same as that of FIG. 4 except that the storage unit 28 for giving the initial value is connected.

In this case, the entire frequency band is adjusted when the device is installed and adjusted.
Measurement signal S generated by the signal generator 3a₁(Δf_Four)
Is selected by the switch 3c, and all frequencies of the signal transmission system 1 to be measured are selected.
Several bands Δf_FourTransfer characteristic h_f4(T) is the initial transmission characteristic
It is measured by the sex measuring section 29. At this time, h_f1(T), h_f2
Each parameter of (t) is also measured. Next, the calculation result
Are stored in the storage unit 28. Specific frequency band Δf₁The biography of
Reach h_f1To start the measurement of (t),
Signal S generated by the signal generator 3a₁(Δf_Four) Is BE
The switch 3c is set so as to pass through F3b. Storage unit 28
The data stored in is the specific frequency band Δf₁In
It is sent to the transfer characteristic calculation unit 4b during the transfer characteristic measurement,
It is used as initial data for correcting the reflection characteristic. here
And the entire frequency band Δf_FourTransfer characteristic h_f4(T) is h_f4(T) = h_f1(T) + h_f2(T) + h_f5It can be expressed as (t) (3). h_f5(T) is the band Δf_Five= Δf_Four-Δf₁−
Δf₂Is a transfer characteristic function of. Δf_FiveTo shut off
Than h_f3(T) = h_f1(T) + h_f2(T) ... (4) is obtained. h_f3(T) is Δf₃= Δf₁+ Δf₂Transmission characteristics
It is a sex function. Using equations (1) and (2), h_f3(T) = Σa_nδ_f1(T-d_n) + Σa_n′ δ_f2(T-d_n′ ) ... (5) is modeled. Σ is the sum for the order n. here
The reflection characteristics of the wall are flat with respect to changes in frequency.
Then, a_n= A_n′ , D_n= D_n′  However, since it generally has frequency characteristics,_n≠ a_n′ , D_n≠ d_n′  Becomes Therefore, as the initial data,_n, D_nWhen
a_n′ , D_n′ Create a correspondence table with and change the delay time and amplitude
A extracted by the parameter extraction unit 4a_n′ , D_n′ Or
From the correspondence table_n, D_nTo select a specific frequency band Δf₁
Calculate the transfer characteristics of. That is, the transfer characteristic calculation unit 4b
A input from the parameter extraction unit 4a_n′, D_n′ And pair
A to respond_n, D_nMemory address where is stored
A_nIs given to the storage unit 28, the storage unit 28 is designated.
Address data a_n, D_nIs given to the transfer characteristic calculation unit 4b.
Get The transfer characteristic calculation unit 4b is a_n, D_nMore h_f1(T)
And T if necessary_f1Calculate (ω).

FIG. 8 is a view for explaining an echo canceller in which the transfer characteristic measuring device 2 of FIG. 7 is incorporated. The parts corresponding to those of FIGS. FIG. 9 is a block diagram of the echo canceller of FIG.
It is a figure explaining the case where howling is suppressed using A), the same code | symbol is attached | subjected to the part corresponding to FIG. 6, FIG. 8, and a duplicate description is abbreviate | omitted.

[0023]

As described above, the transfer characteristic of the present invention
According to the measuring device, a specific frequency band Δf can be used except when adjusting the installation.
₁Outside frequency component Δf₂Measuring signal S with only₁(Δ
f₂), The specific frequency band Δf₁In
Measurement signal S₁(Δf₂) Is avoided, the conventional technique
Specific frequency band Δf during measurement, which was difficult with surgery
₁Is available.

Therefore, the echo canceller constructed by using the measuring apparatus of the present invention can measure the transfer characteristic of the acoustic path including the speaker and the microphone even during the double talk in which the voice signals of the transmitting and receiving voices are simultaneously flowing. The amount of echo cancellation can be increased. Further, since the loudspeaker system (PA) incorporating the echo canceller of the present invention can sufficiently suppress howling, it is suitable for use in a theater, a concert hall, a large conference hall, a party hall, karaoke and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a transfer characteristic measuring device according to the invention of claim 1;

FIG. 2 is a block diagram of an echo canceller using the transfer characteristic measuring device of FIG.

FIG. 3 is a block diagram of a loudspeaker using the echo canceller of FIG.

FIG. 4 is a block diagram showing an embodiment of a transfer characteristic measuring device according to the invention of claim 2;

5 is a block diagram of an echo canceller using the transfer characteristic measuring device of FIG.

6 is a block diagram of a loudspeaker using the echo canceller of FIG.

FIG. 7 is a block diagram showing an embodiment of a transfer characteristic measuring device according to the invention of claim 3;

8 is a block diagram of an echo canceller using the transfer characteristic measuring device of FIG. 7.

9 is a block diagram of a loudspeaker system using the echo canceller of FIG.

FIG. 10 is a block diagram of a conventional transfer characteristic measuring device.

[Explanation of symbols]

 1 measurement object (signal) transfer system 1a input terminal 1b output terminal 2 transfer characteristic measuring device 2a measurement signal input terminal 2b measurement signal output terminal 2c measurement result output terminal 2d characteristic frequency band signal output terminal 3 measurement signal generation section 3a full frequency band Signal generating unit 3b BEF 3c Switching device 4 Transfer characteristic prediction calculating unit 4'Transfer characteristic measuring unit 4a Delay time and amplitude change parameter extracting unit 4b Transfer characteristic calculating unit 5 Signal separating unit 11 Input terminal 12 Adder 13 Speaker amplifier 14 Speaker 15 Transfer characteristic simulation unit 16 Output terminal 17 Subtractor 18 Microphone amplifier 19 Microphone 21 Amplifier 21a Amplifier input terminal 21b Amplifier output terminal 28 Storage unit 29 Initial transfer characteristic measuring unit 100 Echo canceller 200 Loudspeaker

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junko Shimizu 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (6)

[Claims] 1. A transfer characteristic measuring apparatus for measuring the transmission characteristics of the measuring object having a transfer frequency band F (signal) specific transmission system a frequency band Δf ₁ (F⊃Δf _1), the specific frequency band Delta] f ₁ outside the non Signal of specific frequency band Δf ₂ (however, Δf ₂ ⊆ F-Δf ₁ ) [S ₁ (Δf ₂ )]
When the output of the measurement signal generating means and the output of the measurement signal generating means are input to the measurement target transfer system, a non-specific frequency band Δ
f ₂ of the signal [S ₃ (Δf _2)] and the signal separating means for extracting a signal extracted by the signal separating means [S ₃ (Δf _2)]
And a means for predicting and calculating a transfer characteristic in the specific frequency band Δf ₁ of the transfer system to be measured from the output [S ₁ (Δf ₂ )] of the measurement signal generating means. apparatus. 2. The transfer characteristic measuring device according to claim 1, wherein the transfer characteristic predicting / calculating section is composed of a delay time / amplitude change parameter extracting means and a transfer characteristic calculating means, and the delay time / amplitude change parameter thereof. The extraction means models the transfer characteristic function h _f2 (t) in the non-specific frequency band Δf ₂ of the transmission system to be measured by n impulse response sequences of a filter that passes only the non-specific frequency band Δf ₂ , and h _{f2 (t) = Σa n δ f2} (t-d n) ( but, a _n parameters representing the amplitude variation, d _n is a parameter representing the delay time, t is time, [delta] _f2 is the only non-specified frequency band Delta] f ₂ The output of the measurement signal generating means [S
₁ (Δf _2)] and the a _n from the peak amplitude value of the cross-correlation function of the non-specified frequency band Delta] f ₂ of the signal separated [S ₃ (Δf _2)] by the signal separating means, a peak on the time axis The transfer characteristic calculating means estimates the d _n from the position, and the transfer characteristic calculating means uses the delay time, the amplitude change parameter a _n and the delay time parameter d _n estimated by the amplitude change parameter extracting means, modeled by n impulse response series of filter which passes only a specific frequency band Delta] f ₁ specific frequency band Delta] f ₁ of the transfer characteristic function _{h f1 (t), h f1} (t) = Σa n δ f1 (t- d _n ) (However, δ _f1 is the impulse response of the filter that passes only the specific frequency band Δf ₁ , and δ _f1 = δ _f3 −δ _f2
Is. Here, δ _f3 is the impulse response of the filter that passes only the frequency band Δf ₃ , and F ⊇ Δf ₃ = Δ
A transfer characteristic measuring device, characterized in that it calculates f ₁ + Δf ₂ ). 3. The transfer characteristic measuring device according to claim 2, wherein the measurement signal generating means is at least a specific frequency band Δ.
All frequency band signal generating means for generating a measurement signal over the entire frequency band Δf ₄ (where F ⊇ Δf ₄ ⊇ Δf ₁ + Δf ₂ ) including f ₁ and the non-specific frequency band Δf ₂ and the all frequency band signal A BEF (band stop filter) that cuts off a specific frequency band Δf ₁ of the measurement signal generated by the generation means, and an output of the full frequency band signal generation means during installation adjustment of the transfer characteristic measuring device, and an output of the BEF during measurement. And a switching means for switching each and outputting to the outside, and at the time of installation and adjustment of the measuring device, the measurement signal of the entire frequency band generated by the measurement signal generating means [S ₁ (Δf ₄ )]
And the output signal [S ₂ (Δf ₄ )] of the signal transmission system to be measured when the measurement signal of the entire frequency band is input, the parameters of the initial transfer characteristic function h _f2 (t) of the specific frequency band Δf ₂ (A _n ′, d _n ′) and non-specific frequency band Δf
Parameters of the _first initial transmission characteristic function _{h f1 (t) (a n} ,
initial transfer characteristic measuring means for measuring d _n ), and parameters (a _n , a _{n of} at least the initial transfer characteristic function h _f1 (t) measured by the initial transfer characteristic measuring means)
d _n ), and the transfer characteristic function h _f1 (t) corresponding to the parameters (a _n ′, d _n ′) of the transfer characteristic function h _f2 (t).
And a storage means for giving the transfer characteristic prediction calculation means the parameters (a _n , d _n ) of 1. 4. The function according to claim 1, wherein the signal separating means has a function of extracting a signal [S ₃ (Δf ₂ )] in a non-specific frequency band Δf ₂ from the output of the transmission system to be measured. Signal of a specific frequency band Δf ₁ [S ₄ (Δf
₁ )] is a transfer characteristic measuring device having a function of extracting. 5. A transmission / reception transmission circuit is composed of a reception side transmission circuit for outputting an input reception voice signal to a speaker and a transmission side transmission circuit for outputting a transmission voice signal input from a microphone to the outside. An echo canceller that is inserted in the middle of a transmission / reception transmission circuit and cancels a received voice component (echo component) emitted from the speaker included in the microphone output, the transfer characteristic measuring device according to claim 4, and the transfer characteristic. The transfer characteristic measuring device has a simulation unit, an adder, and a subtracter, and the transfer characteristic measuring device sets a transmission and reception voice frequency band to a specific frequency band Δf ₁ and a transfer system including the speaker or the microphone to the measurement target transfer system. And the microphone output is input to the signal separation unit, and the output of the measurement signal generating means is given to one input terminal of the adder,
The transfer characteristic simulating section is controlled by the output of the transfer characteristic predicting / calculating means, and the signal [S ₄ (Δf ₁ )] in the specific frequency band separated by the signal separating section is applied to one input terminal of the subtractor. The adder adds the received voice signal and the output of the measurement signal generating means and sends the output to the speaker, the transfer characteristic simulation unit is controlled by the output of the transfer characteristic prediction calculating means, It has a function of simulating a transfer characteristic of a transfer system composed of a speaker or a microphone, inputs the received voice signal, gives its own output (r) to the other input terminal of the subtractor, and the subtractor The signal (r) input from the transfer characteristic simulating unit is subtracted from the signal of a specific frequency band [S ₄ (Δf ₁ )] input from the signal separating means, and the subtracted signal is the transmission voice signal (S ) As Characteristic, echo canceller. 6. A loudspeaker device comprising the echo canceller according to claim 5, an amplifier, a microphone, and a speaker, wherein the echo canceller inputs the output of the microphone to the signal separation means and performs the addition. The addition output of the amplifier is input to the speaker, the output of the subtractor is input to the amplifier, and the output of the amplifier is input to the transfer characteristic simulating unit and the adder instead of the received voice signal. Characterized loudspeaker.