CN102118678A - Method and system for measuring speaker parameters by using current sensor - Google Patents
Method and system for measuring speaker parameters by using current sensor Download PDFInfo
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Abstract
The invention provides a method for measuring speaker parameters by using a current displacement sensor, and provides a test system for implementing the method. The method comprises the following steps: exciting a measured device by adopting a stepping swept-frequency signal; measuring voltage signals at the two ends of the measured device as well as a current response signal flowing through the measured device at the same time; and substituting the signals into a linear module and a large-signal Volterra model of the speaker, and acquiring linear parameters and non-linear parameters of the speaker through system identification. The method does not need a laser sensor, the cost is low, and the non-linear parameter identification technology of the speaker can be applied to the production detection of speaker products.
Description
Technical field
The invention belongs to the measurement method of parameters and the measuring system of loud speaker, specifically, obtain the method and system of a plurality of parameters of electro-acoustic product by loudspeaker wiring terminal voltage and load current are carried out Nonlinear Systems Identification.Can be widely used in the speaker product quality testing and end product of electroacoustic enterprise.
Background technology
The meaning of loud speaker parameter measurement:
The loud speaker parameter has important effect to speaker design, manufacturing and quality control.Since 1970, Australian A. N. Thiele and R. H. Small have proposed the T/S parameter of speaker system, make the possibility that is designed to that realizes speaker system by the filter synthesis method.Small-signal parameter wherein is to record under the negligible situation of distortion in small signal driving, system's output, so claim linear dimensions again.This parameter can be used for characterizing the low frequency performance of loud speaker, should be in the quality control of speaker design and production.
Since 1980, the researcher begins the large-signal performance of loud speaker is carried out various quantitative analysiss.Many models are used to the nonlinear characteristic analysis of loud speaker, as Volterra model (Volterra), state-space model, finite element and boundary element model, Hammerstein and Wiener model or the like.By loud speaker modeling and large signal parameters are measured, can set up the computer model of tested speaker, can understand the expection electroacoustic performance of this design in the speaker design stage, the small lot pilot stage can measuring samples parameter with checking with revise design, can be used for accident analysis and process modification in the volume production stage.
The measurement of the parameter measurement of loud speaker, particularly nonlinear parameter is the difficult problem of electroacoustic measurement circle, and the measuring technique and the method for existing linear dimensions and nonlinear parameter are as follows:
1) by changing the method for diaphragm mass, cavity volume: measure the impedance operator of loud speaker, thereby obtain
f s ,
Q Ts Etc. parameter, utilize additional mass or additional volume method to measure impedance operator once more afterwards, thereby obtain
f s ',
Q Ts ' etc., and calculate all linear dimensions.This method shortcoming is: 1, generally need secondary to measure troublesome poeration; 2, additional mass or additional volume method have been destroyed the original operating state of loud speaker to a certain extent, so the result is inaccurate; 3, the secondary measurement causes vibrating diaphragm compliance, voice coil temperature to change, and is influential to measurement result.
2) by measuring the method for acoustic pressure, current response: United States Patent (USP) 6269318 (Method For determining
Transducer linear operation parameters) method that working voltage-acoustic pressure transfer function and electric current-acoustic pressure transfer function is measured linear parameter of loudspeaker has been proposed.The microphone that this method is used is subject to ambient noise, ambient temperature and humidity influence, and this method need provide the test casing of a known volume as the condition of accurately measuring simultaneously.
3) measure by changing the equilbrium position: openly patent of invention CN200510041525.0 is (based on raising of System Discrimination
Sound device unit method for measuring non-linear parameters) uses the method for the adjustable direct current of feeding to make the certain position of voice coil loudspeaker voice coil skew, under different voice coil loudspeaker voice coil displacements, measure impedance, and anti-Model Distinguish obtains nonlinear parameter according to the loudspeaker unit nonlinear resistance.This method need use adjustable DC source to loud speaker output offset electric current, and this electric current can make voice coil temperature rise.Because the equilbrium position of vibrating diaphragm changes, speaker operation is at special state in addition.Also have the scholar to propose to use cavity and air pump to change the method for vibrating diaphragm equilbrium position, but equipment needed thereby is comparatively special, also has the problem that changes the loud speaker normal operating conditions simultaneously.
4) use laser sensor to measure the displacement of the diaphragm of loudspeaker.At first, laser measurement is a non-cpntact measurement, need not to change equilbrium position, quality of vibrating diaphragm etc., and speaker operation is in normal condition; Secondly, laser measurement is not affected by noise, and it is little that laser sensor is influenced by humiture.Yet under production line environment, or in the speaker system product, use laser sensor to need special support, need to guarantee environment friction interference etc., these condition restriction its can only be applied in research and development and the small lot quality testing.
Summary of the invention
The present invention is directed to above-mentioned deficiency, propose a kind of method and system of using current sensor measurement loud speaker linearity and nonlinear parameter.
The use current sensor measurement loud speaker linearity that the present invention proposes and the method for nonlinear parameter may further comprise the steps:
1) the pumping signal generation module of being located in the computer generates pumping signal, and this pumping signal is a digital signal, and this digital signal is exported after the digital-to-analogue analog-to-digital conversion module is converted to analog signal;
2) power amplifier exports measured device to after the analog signal of digital-to-analogue analog-to-digital conversion module output is amplified;
3) the voltage tester anchor clamps are measured the voltage signal at measured device two ends, current sensor measurement flows through the current responsing signal of measured device, current signal that obtains and voltage signal input digital-to-analogue analog-to-digital conversion module, send into response signal collection and processing module after being converted to digital signal by the digital-to-analogue analog-to-digital conversion module, again after treatment signal is input to linear dimensions recognition module and nonlinear parameter recognition module, handle through the identification processing of the linear dimensions identification model of linear parameter identification module and large-signal Volterra (Volterra) Model Distinguish of nonlinear parameter recognition module, obtain the linear dimensions and the nonlinear parameter of loud speaker.
The linear dimensions of loud speaker comprises
R e,
l 0,
L Ces ,
R Es With
C Mes The nonlinear parameter number of loud speaker comprises
Bl(
x),
K(
x) and
Le(
x), wherein:
Bl(
x)?=?
b 0?+?
b 1 x?+?
b 2 x 2
K(
x)?=?
k 0?+?
k 1 x?+?
k 2 x 2
L e (
x)?=?
l 0?+?
l 1 x?+?
l 2 x 2 。
Measured device comprises that moving-coil speaker unit or loud speaker close case system or loud speaker phase inverting box system.
Because loud speaker can be considered nonlinear device when large-signal encourages, use the frequency excitation loud speaker more than 2, will produce a plurality of harmonic waves and intermodulation response item, these responses might overlap on frequency, cause measuring and lost efficacy, so pumping signal of the present invention is selected single-frequency or two-frequency signal for use.
If pumping signal adopts simple signal, be stepping logarithm swept-frequency signal, its form is:
Wherein,
UBe the pumping signal amplitude,
w iBe driving frequency,
w i+ 1
Generally press
Oct=1/3,1/6,1/12,1/24 and other octave standards or choose by logarithmic relationship, promptly
w i+ 1
/
w i =2
Oct t I+1 -t i Be a certain driving frequency of pumping signal
w i Duration.Amplitude does not produce and impacts the mild transition in ground when guaranteeing that two frequencies are switched, and needs to consider the continuity of phase place.So need be according to a last signal termination phase place
If pumping signal adopts two-frequency signal, its form is:
Wherein, the 1st is amplitude
U 1, fixed frequency is
w 0 Pumping signal, be used to the vibrating diaphragm displacement that provides enough, be called the displacement excitation signal; The 2nd is amplitude
U 1Stepping logarithm swept-frequency signal;
u(
t) be step signal.
If pumping signal adopts simple signal, need to measure 2 overtones bands of fundamental frequency and the spectral line at 3 overtones band places, obtain the amplitude and the phase place of 2 subharmonic, 3 subharmonic;
If pumping signal adopts two-frequency signal, need to measure 2 rank and the 3 rank intermodulation responses that swept-frequency signal is a centre frequency.
When the voltage at electric current that flows through measured device and two ends thereof is known, at the equivalent oscillating mass of known measured device
M Ms Prerequisite under, pass through impedance operator
Z(
s) formula, identification obtains linear dimensions; By the relational expression of voltage-displacement Volterra kernel function and electric current-displacement Volterra kernel function, adopt the nonlinear least square method identification to obtain nonlinear parameter.
Impedance operator
Z(
s) be:
The relational expression of voltage-displacement Volterra kernel function is:
The relational expression of voltage-displacement Volterra kernel function is:
A kind of system that uses current sensor measurement loud speaker parameter of the present invention comprises computer, and computer is connected with the digital-to-analogue analog-to-digital conversion module, and the digital-to-analogue analog-to-digital conversion module is connected with power amplifier, four line voltage tester anchor clamps, current sensor.
Be provided with pumping signal generation module, response signal collection and the processing module, the line that generate pumping signal in the computer
Property parameter identification module, nonlinear parameter recognition module and Subscriber Interface Module SIM, pumping signal generation module, response signal collection and processing module are connected with the digital-to-analogue analog-to-digital conversion module, Subscriber Interface Module SIM is connected with pumping signal generation module, linear dimensions recognition module, nonlinear parameter recognition module, and linear dimensions recognition module, nonlinear parameter recognition module and response signal collection and processing module are connected.
A kind of method of only using current sensor that the loud speaker nonlinear parameter is carried out identification of the present invention is not subjected to the restriction of environment, cost, can be applicable to product of production line quality testing and speaker system product and detects.
Description of drawings
Fig. 1 is for using the method module map of current sensor measurement loud speaker parameter.
Fig. 2 is for using the system and device module map of current sensor measurement loud speaker parameter.
Fig. 3 is the dynamo-electric equivalent circuit diagram of the large-signal of loud speaker.
Fig. 4 is the large-signal Volterra model block diagram of loud speaker.
Fig. 5 is the time-frequency figure of current responsing signal.
Fig. 6 is the displacement fundamental frequency, 2 times of embodiment tested speaker and 3 subharmonic response amplitudes and by driving voltage, voice coil loudspeaker voice coil current forecasting comparison diagram as a result.
Fig. 7 is the displacement fundamental frequency, 2 times of embodiment tested speaker and 3 subharmonic response phases and by driving voltage, voice coil loudspeaker voice coil current forecasting comparison diagram as a result.
Fig. 8 is the impedance operator measurement result and the fitting result comparison diagram of embodiment tested speaker.
Fig. 9 is differential equation numerical simulation result and experimental result comparison diagram.
Embodiment
Below in conjunction with drawings and Examples, the present invention is further illustrated.
As shown in the figure, the method for the use current sensor measurement loud speaker parameter of the present invention's proposition may further comprise the steps:
1) the pumping signal generation module of being located in the computer 71 generates pumping signal, and this pumping signal is a digital signal, and this digital signal is exported after digital-to-analogue analog-to-digital conversion module 8 is converted to analog signal;
2) power amplifier 9 exports measured device 6 to after the analog signal of digital-to-analogue analog-to-digital conversion module 8 outputs is amplified;
3) voltage tester anchor clamps 10 are measured the voltage signal at measured device 6 two ends, current sensor 11 is measured the current responsing signal that flows through measured device, current signal that obtains and voltage signal input digital-to-analogue analog-to-digital conversion module 8, send into response signal collection and processing module after being converted to digital signal by digital-to-analogue analog-to-digital conversion module 8, again after treatment signal is input to linear dimensions recognition module 3 and nonlinear parameter recognition module 4, handle through the identification processing of the linear dimensions identification model of linear parameter identification module 3 and large-signal Volterra (Volterra) Model Distinguish of nonlinear parameter recognition module 4, obtain the linear dimensions and the nonlinear parameter of loud speaker.
The linear dimensions of loud speaker comprises
R e,
l 0,
L Ces ,
R Es With
C Mes The nonlinear parameter number of loud speaker comprises
Bl(
x),
K(
x) and
Le(
x), wherein:
Bl(
x)?=?
b 0?+?
b 1 x?+?
b 2 x 2
K(
x)?=?
k 0?+?
k 1 x?+?
k 2 x 2
L e (
x)?=?
l 0?+?
l 1 x?+?
l 2 x 2 。
Measured device 6 comprises that moving-coil speaker unit or loud speaker close case system or loud speaker phase inverting box system.
Because loud speaker can be considered nonlinear device when large-signal encourages, use the frequency excitation loud speaker more than 2, will produce a plurality of harmonic waves and intermodulation response item, these responses might overlap on frequency, cause measuring and lost efficacy, so pumping signal of the present invention is selected single-frequency or two-frequency signal for use.
If pumping signal adopts simple signal, be stepping logarithm swept-frequency signal, its form is:
。
Wherein,
UBe the pumping signal amplitude,
w iBe driving frequency,
w i+ 1
Generally press
Oct=1/3,1/6,1/12,1/24 and other octave standards or choose by logarithmic relationship, promptly
w i+ 1
/
w i =2
Oct t I+1 -t i Be a certain driving frequency of pumping signal
w i Duration.Amplitude does not produce and impacts the mild transition in ground when guaranteeing that two frequencies are switched, and needs to consider the continuity of phase place.So need be according to a last signal termination phase place
If pumping signal adopts two-frequency signal, its form is:
Wherein, the 1st is amplitude
U 1, fixed frequency is
w 0 Pumping signal, be used to the vibrating diaphragm displacement that provides enough, be called the displacement excitation signal; The 2nd is amplitude
U 1Stepping logarithm swept-frequency signal;
u(
t) be step signal.
If pumping signal adopts simple signal, need to measure 2 overtones bands of fundamental frequency and the spectral line at 3 overtones band places, obtain the amplitude and the phase place of 2 subharmonic, 3 subharmonic;
If pumping signal adopts two-frequency signal, need to measure 2 rank and the 3 rank intermodulation responses that swept-frequency signal is a centre frequency.
When the voltage at electric current that flows through measured device and two ends thereof is known, at the equivalent oscillating mass of known measured device
M Ms Prerequisite under, pass through impedance operator
Z(
s) formula, identification obtains linear dimensions; By the relational expression of voltage-displacement Volterra kernel function and electric current-displacement Volterra kernel function, adopt the nonlinear least square method identification to obtain nonlinear parameter.
Impedance operator
Z(
s) be:
The relational expression of voltage-displacement Volterra kernel function is:
The relational expression of voltage-displacement Volterra kernel function is:
When digital-to-analogue analog-to-digital conversion module 8 exports pumping signal to power amplifier 9, gather the electric current and the displacement instantaneous value of loud speaker, and signal delivered to response signal collection and processing module 2, response signal collection and processing module 2 split the signal that the collects frequency by pumping signal, and do fast fourier transform, obtain fundamental frequency response and the harmonic wave or the intermodulation response of each driving frequency correspondence.
Linear dimensions recognition module 3 is set up the linear dimensions identification model
Linear dimensions recognition module 3 is based upon on the basis of loud speaker lumped parameter electromechanical analogy equivalent electric circuit, sets up the following differential equation by equivalent electric circuit:
When speaker operation during in little amplitude state, formula (3) and formula (4) are carried out the Laplace conversion, can be written as
Because vibrating diaphragm displacement
xIt is very little,
Bl(
x),
Le(
x) and
K(
x) can be considered constant, be designated as respectively
b 0,
l 0With
k 0, in formula (5) and the formula (6)
DLe(
x)/
DxItem is 0.So can obtain the impedance operator of loud speaker
Z(
s) and voltage-displacement linear transfer function
H U1 (
s), they are respectively:
。
The impedance operator that measures is the mould values of power amplifier 9 output voltages than the electric current of the loud speaker of flowing through.
Use nonlinear least square fitting, can in the hope of
R e,
l 0,
k 0/
b 0 2,
R Ms/
b 0 2With
M Ms/
b 0 2Totally 5 values.Because
M MsBe a value that is not subject to the environmental change influence, under the situation that error allows, can be made as known quantity.So can obtain
b 0And calculate
k 0With
R Ms
Non-The linear dimensions recognition module is set up the nonlinear parameter identification model
When speaker operation during at the large amplitude state, because parameter
Bl(
x),
Le(
x) and
K(
x) along with the vibrating diaphragm displacement
xVariation and change, its input with output no longer be linear relationship.Use Volterra progression to find the solution the equation group of formula (3) and formula (4) composition for this reason, obtain input voltage and the relation of exporting displacement.According to the Volterra series theory, Nonlinear system response can be expressed as the form of the convolution of each rank kernel function and pumping signal, and suc as formula (9), its block diagram as shown.
In the formula,
u(
t) be input,
h 11 rank kernel function of expression system is linear impulse response,
h 2With
h 32 rank and the 3 rank kernel functions of representing system respectively.
Work as input signal
x(
t)=exp (
s 1 t) time, system linear response expression formula is:
y(
t)?=?
H 1(s
1)exp(
s 1 t) （13）
Except that linear response, also has the harmonic response more than 2 times of input signal in the output.
Input signal
x(
t)=
Exp(
s 1 t)+
Exp(
s 2 t) time, only consider the response output of 2 rank, have
y?(
t)?=
?H 1 (s
1)?exp(
s 1 t)?+
?H 1(s
2)?exp(
s 2 t)?+
H 2 (s 1,
s 1)?exp(2
s 1 t)?+
?H 2(
s 2,
s 2)?exp(2
s 2 t)?+?2
H 2(
s 1,
s 2)?exp(
s 1 t+s 2 t) （14）
Preceding two are linear response in the formula.3rd, 42 subharmonic distortions that correspondence system.
H 2(
s 1,
s 2) be symmetrical, have
H 2(
s 1,
s 2)=
H 2(
s 2,
s 1), so the 5th coefficient is 2, corresponding the intermodulation distortion of system.
Input signal
x(
t)=exp (
s 1 t)
+Exp (
s 2 t)
+Exp (
s 3 t) time, only consider the response output of 3 rank, have
y(
t)?=?
y 1(
t)?+?
y 2(
t)?+?
y 3(
t)+…… （15）
Wherein,
y 1(
t) be that the response of 1 rank kernel function is linear response.
y 2(
t) with
y 3(
t) be respectively the response of 2,3 rank kernel functions, constitute by harmonic response and intermodulation response.Its concrete form is as follows:
y 1(
t)?=
?H 1(
s 1)?exp(
s 1 t)?+
?H 1(
s 2)?exp(
s 2 t)?+
?H 1(
s 3)?exp(
s 3 t) （16）
y 2(
t)?=
?H 2(
s 1,
s 1)?exp(2
s 1 t)+
?H 2(
s 2,
s 2)?exp(2
s 2 t)?+?
H 2(
s 3,
s 3)?exp(2
s 3 t)?+
2
H 2(
s 1,
s 2)exp(
s 1 t+
s 2 t)?+?2
H 2(
s 1,
s 3)exp(
s 1 t+
s 3 t)?+?2
H 2(
s 2,
s 3)?exp(
s 2 t+
s 3 t) （17）
y 3(
t)?=
?H 3(
s 1,
s 1,
s 1)?exp(3
s 1 t)?+
?H 3(
s 2,
s 2,
s 2)?exp(3
s 2 t)?+?
H 3(
s 3,
s 3,
s 3)?exp(3
s 3 t)?+
3
H 3(
s 1,
s 1,
s 2)exp(2
s 1 t+
s 2 t)?+3
H 3(
s 1,
s 1,
s 3)exp(2
s 1 t+
s 3 t)?+?3
H 3(
s 2,
s 2,
s 1)exp(
s 1 +2
s 2 t)?+
3
H 3(
s 2,
s 2,
s 3)exp(2
s 2 t+
s 3 t)?+3
H 3(
s 3,
s 3,
s 1)exp(
s 1 +2
s 3 t)?+?3
H 3(
s 3,
s 3,
s 2)exp(
s 2 t+2
s 3 t)?+
6
H 3(
s 1,
s 2,
s 3)?exp(
s 1 t+
s 2 t+
s 3 t) （18）
Preceding 3 of formula (14) is the responses of 2 subharmonic, and back 3 is 2 intermodulation response.Similar with it, 3 subharmonic responses referring to
y 3(
t) preceding 3, its remainder is 3 intermodulation response item.As seen, along with the increase of analyzing exponent number, the quantity of intermodulation response item significantly increases.For the ease of setting forth, only loud speaker is carried out 1～3 rank Volterra modeling in the specification.
Will
Bl(
x),
K(
x) with
L e (
x) approximate representation is the form of 2 rank power series, and is as follows:
Bl(
x)?=?
b 0?+?
b 1 x?+?
b 2 x 2 （19）
K(
x)?=?
k 0?+?
k 1 x?+?
k 2 x 2 （20）
L e (
x)?=?
l 0?+?
l 1 x?+?
l 2 x 2 （21）
The order input
U=exp (
s 1 t)
+Exp (
s 2 t)
+Exp (
s 3 t), and displacement is the form suc as formula (12), substitution formula (5) and formula (6) can be obtained linear kernel function suc as formula (8) by harmonic wave equilibrium method, and 2,3 rank kernel functions are as follows
Wherein, coefficient
Q i , R i As follows:
By above-mentioned derivation as can be seen, if the linear dimensions of known loudspeaker, and the harmonic wave of the displacement response of known vibrating diaphragm or intermodulation response, can use the nonlinear least-square fitting process to carry out curve fitting, thereby obtain the power series coefficient of nonlinear parameter
b 1,
k 1,
l 1With
b 2,
k 2,
l 2
If need known vibrating diaphragm displacement response, just need measure by vibrating sensor.For fear of using vibrating sensor easily affected by environment, need from the voice coil loudspeaker voice coil electric current, predict the displacement of loud speaker this moment.Similar with said method, can establish the single-frequency current signal excitation form of separating of loud speaker down, obtain electric current linear transfer function, 2 rank and 3 rank Volterra kernel functions by harmonic wave equilibrium method.
If flow into the electric current of loudspeaker voice coil
i(t)?=?
A 1exp(
s 1 t)?+?
A 2exp(
s 2 t)?+?
A 3exp(
s 3 t) (24
)
Output is made as
y(t)?=?
y DC ?+?
y 1(
t)?+?
y 2(
t)?+
?y 3(
t) (
25)
With formula (21) and formula (22) substitution formula (6), arrangement frequency identical entry can obtain Volterra kernel function expression formula, and is as follows
In the formula,
H Ix1
(
s) be the linear kernel function of loud speaker of current drives,
H Ix2
(
s 1,
s 2) and
H Ix3
(
s 1,
s 2,
s 3) be respectively 2 rank and 3 rank Volterra kernel functions.
For the power amplifier 9 of driven, if the nonlinear distortion of ignoring in the circuit influences, output only comprises the linear response of pumping signal in the voltage at loud speaker two ends.Loud speaker can generate motional electromotive force after being subjected to the electromagnetic force driving to begin vibration in voice coil loudspeaker voice coil
ε=
Bl(
x)
vThe vibration of this electromotive force and vibrating diaphragm is closely related, and the distortion of displacement response is embodied in motional electromotive force in the vibrational system
εIn.Change
εMake electric current in loop change, so comprise the information of this Non-Linear Vibration in the electric current.By current sensor, can measure tangible nonlinear distortion, as.Utilize 1～3 rank electric current under the current drives-displacement Volterra kernel function to obtain the displacement response of vibrating diaphragm.Can obtain the displacement fundamental frequency response by 1 rank Volterra kernel function under the current drives.
The response of 2 order harmonicses is:
The response of 3 order harmonicses is:
The item of its acceptance of the bid dotted line underscore is 1～3 rank response item.Response item more than 3 rank is ignored, and put in order, can obtain the relational expression of current response and displacement response by the frequency of response.Suc as formula (32), driving voltage displacement response of predicting and the displacement response that flows through the current forecasting of voice coil loudspeaker voice coil are placed on both members, can obtain an equation group.Do not occur displacement in the equation group, voltage only occurred
UAnd current response
I 1～
I 3, these parameters device measuring by experiment obtain.Each kernel function expression formula in the equation group is known, and its nonlinear parameter the unknown can adopt nonlinear least square fitting that the nonlinear parameter identification is come out.
A kind of system that uses current sensor measurement loud speaker parameter of the present invention, comprise computer 7, computer 7 is connected with digital-to-analogue analog-to-digital conversion module 8, and digital-to-analogue analog-to-digital conversion module 8 is connected with power amplifier 9, four line voltage tester anchor clamps 10, current sensor 11.
Be provided with in the computer 7 the pumping signal generation module 1, response signal collection and the processing module 2 that generate pumping signal,
Linear dimensions recognition module 3, nonlinear parameter recognition module 4 and Subscriber Interface Module SIM 5, pumping signal generation module 1, response signal collection and processing module 2 are connected with digital-to-analogue analog-to-digital conversion module 8, Subscriber Interface Module SIM 5 is connected with pumping signal generation module 1, linear dimensions recognition module 3, nonlinear parameter recognition module 4, and linear dimensions recognition module 3, nonlinear parameter recognition module 4 and response signal collection and processing module 2 are connected.
Subscriber Interface Module SIM 5 provides functions such as test interface, the judgement of user's input parameter and preservation, measurement result demonstration.
Moving the software that comprises method of testing of the present invention in the computer 7, control digital-to-analogue analog-to-digital conversion module 8 is realized calibration and functions such as measurement, parameter identification and demonstration as a result.
Digital-to-analogue analog-to-digital conversion module 8 is realized the mutual conversion of digital signal and analog signal.The pumping signal that pumping signal generation module 1 in the computer 7 generates is a digital signal, is output as analog signal after this module converts.
Now the order by each module of the present invention illustrates its method of testing.
The pumping signal that the embodiment of the invention is selected for use is a simple signal.Before the test, the user need provide the basic parameter of test product to Subscriber Interface Module SIM 5, comprises the voltage amplitude of pumping signal
U, frequency sweep the start-stop frequency
f 1,
f 2And frequency sweep frequency step.Such as
U=1V,
f 1=20Hz,
f 2=20kHz, the frequency sweep frequency is increased progressively by initial frequency by the third-octave relation.
Above-mentioned pumping signal exports power amplifier 9 to by digital-to-analogue analog-to-digital conversion module 8.Power amplifier 9 promotes tested speaker 6 sounding.Digital-to-analogue analog-to-digital conversion module 8 is gathered the voltage of four line voltage tester anchor clamps 10 and the output of current sensor 11, and stores in the computer 6.By calculating, obtain the amplitude and the phase place of fundamental frequency response, 2 subharmonic and the response of 3 subharmonic of each driving frequency correspondence, as 6-Fig. 7.
Flow through measured device 6(loud speaker) the electric current and the voltage at two ends thereof and to flow through the electric current of loud speaker known, so can obtain impedance operator
Z(
s), known
M Ms Prerequisite under identification obtain linear dimensions.Similarly, according to the relational expression of voltage-displacement Volterra kernel function and electric current-displacement Volterra kernel function, adopt the nonlinear least square method identification to obtain nonlinear parameter.
In order to verify identification result, above-mentioned parameter was returned in the differential equation of loud speaker by generation.By numerical method, can calculate linear response, and the harmonic distortion of loud speaker under another voltage, and itself and measurement result are compared.But use error
eThe measurement consistency with measurement result that predicts the outcome,
Wherein
wThe expression weighting function, form is
Use electric current identification nonlinear parameter, and the error that is used for predictive displacement linear response, the response of 2 rank and the response of 3 rank is respectively 4.9%, 18.8% and 28.1%, a little less than the error 6.2%, 11.6% and 11.9% of using laser.
Among the embodiment, digital-to-analogue analog-to-digital conversion module 8 is supported the input of 4 passages, the output of 4 passages, 24 of sampling resolutions, and sample rate reaches as high as 192kHz.Power amplifier 9 power outputs can reach 100W, and distortion is less than 0.001%.The range 40mm of four line voltage tester anchor clamps 10, precision 4mm, the frequency range of Displacement Measurement is direct current～1000Hz.Current sensor 11 is measuring 4 linear heat generation rate resistance, resistance 0.100 Ω.Tested speaker 6 is the auto loud hailer of 6.5 cun of diameters.
Above embodiment only in order to the explanation the present invention and and unrestricted technical scheme described in the invention; Therefore, although this specification has been described in detail the present invention with reference to each above-mentioned embodiment,, those of ordinary skill in the art should be appreciated that still and can make amendment or be equal to replacement the present invention; And all do not break away from the technical scheme and the improvement thereof of the spirit and scope of invention, and it all should be encompassed in the middle of the claim scope of the present invention.
Each meaning of parameters of the present invention sees the following form:
Claims (7)
1. a method of using current sensor measurement loud speaker parameter is characterized in that this method comprises the steps:
1) the pumping signal generation module of being located in the computer generates pumping signal, and this pumping signal is a digital signal, and this digital signal is exported after the digital-to-analogue analog-to-digital conversion module is converted to analog signal;
2) power amplifier exports measured device to after the analog signal of digital-to-analogue analog-to-digital conversion module output is amplified;
3) the voltage tester anchor clamps are measured the voltage signal at measured device two ends, current sensor measurement flows through the current responsing signal of measured device, current signal that obtains and voltage signal input digital-to-analogue analog-to-digital conversion module, send into response signal collection and processing module after being converted to digital signal by the digital-to-analogue analog-to-digital conversion module, again after treatment signal is input to linear dimensions recognition module and nonlinear parameter recognition module, handle through the identification processing of the linear dimensions identification model of linear parameter identification module and the large-signal Volterra Model Distinguish of nonlinear parameter recognition module, obtain the linear dimensions and the nonlinear parameter of loud speaker.
2. the method for use current sensor measurement loud speaker parameter according to claim 1 is characterized in that the linear dimensions of loud speaker comprises
The nonlinear parameter of loud speaker comprises
Wherein:
?
。
3. the method for use current sensor measurement loud speaker parameter according to claim 1 is characterized in that measured device comprises that moving-coil speaker unit or loud speaker close case system or loud speaker phase inverting box system.
4. the method for use current sensor measurement loud speaker parameter according to claim 1 is characterized in that described pumping signal selects single-frequency or two-frequency signal for use;
If pumping signal adopts simple signal, promptly adopt stepping logarithm swept-frequency signal, its form is:
Wherein,
UBe the pumping signal amplitude,
w iBe driving frequency,
w i+ 1
Press
Oct=1/3,1/6,1/12,1/24 and other octave standards or choose by logarithmic relationship, promptly
w i+ 1
/
w i =2
Oct t I+1 -t i Be a certain driving frequency of pumping signal
w i Duration; Amplitude does not produce and impacts the mild transition in ground when guaranteeing that two frequencies are switched, and needs to consider the continuity of phase place; So need be according to a last signal termination phase place
If pumping signal adopts two-frequency signal, its form is:
Wherein, the 1st is amplitude
U 1, fixed frequency is
w 0 Pumping signal, be used to the vibrating diaphragm displacement that provides enough, be called the displacement excitation signal; The 2nd is amplitude
U 1Stepping logarithm swept-frequency signal;
u(
t) be step signal;
If pumping signal adopts simple signal, need to measure 2 overtones bands of fundamental frequency and the spectral line at 3 overtones band places, obtain the amplitude and the phase place of 2 subharmonic, 3 subharmonic;
If pumping signal adopts two-frequency signal, need to measure 2 rank and the 3 rank intermodulation responses that swept-frequency signal is a centre frequency.
5. the method for use current sensor measurement loud speaker parameter according to claim 1 is when is characterized in that voltage when electric current that flows through measured device and two ends thereof is known, at the equivalent oscillating mass of known measured device
M Ms Prerequisite under, pass through impedance operator
Z(
s) formula, identification obtains linear dimensions; By the relational expression of voltage-displacement Volterra kernel function and electric current-displacement Volterra kernel function, adopt the nonlinear least square method identification to obtain nonlinear parameter;
Impedance operator
Z(
s) be:
The relational expression of voltage-displacement Volterra kernel function is:
The relational expression of electric current-displacement Volterra kernel function is:
6. a kind of system that uses current sensor measurement loud speaker parameter according to claim 1, comprise computer, it is characterized in that computer is connected with the digital-to-analogue analog-to-digital conversion module, the digital-to-analogue analog-to-digital conversion module is connected with power amplifier, four line voltage tester anchor clamps, current sensor.
7. a kind of system that uses current sensor measurement loud speaker parameter according to claim 6, it is characterized in that being provided with in the computer pumping signal generation module that generates pumping signal, response signal is gathered and processing module, the linear dimensions recognition module, nonlinear parameter recognition module and Subscriber Interface Module SIM, the pumping signal generation module, response signal collection and processing module are connected with the digital-to-analogue analog-to-digital conversion module, Subscriber Interface Module SIM and pumping signal generation module, the linear dimensions recognition module, the nonlinear parameter recognition module connects, the linear dimensions recognition module, the nonlinear parameter recognition module is connected with response signal collection and processing module.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6058195A (en) * | 1998-03-30 | 2000-05-02 | Klippel; Wolfgang J. | Adaptive controller for actuator systems |
| CN1761366A (en) * | 2005-08-18 | 2006-04-19 | 南京大学 | Method for measuring non-linear parameters of speaker unit based on system identification |
| US20070253562A1 (en) * | 2006-04-27 | 2007-11-01 | Kite Thomas D | Method and apparatus for measuring characteristics of an audio system using a tapered chirp |
| CN101442698A (en) * | 2008-09-26 | 2009-05-27 | 嘉兴中科声学科技有限公司 | Method for measuring linear parameter of loudspeaker |
-
2011
- 2011-04-02 CN CN201110083837.3A patent/CN102118678B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6058195A (en) * | 1998-03-30 | 2000-05-02 | Klippel; Wolfgang J. | Adaptive controller for actuator systems |
| CN1761366A (en) * | 2005-08-18 | 2006-04-19 | 南京大学 | Method for measuring non-linear parameters of speaker unit based on system identification |
| US20070253562A1 (en) * | 2006-04-27 | 2007-11-01 | Kite Thomas D | Method and apparatus for measuring characteristics of an audio system using a tapered chirp |
| CN101442698A (en) * | 2008-09-26 | 2009-05-27 | 嘉兴中科声学科技有限公司 | Method for measuring linear parameter of loudspeaker |
Non-Patent Citations (1)
| Title |
|---|
| 刘春晖， 杨宗凯，刘泉: "基于Volterra模型的一类通信系统的参数辨识", 《华中理工大学学报》, no. 12, 31 December 1997 (1997-12-31) * |
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