RU2542637C1 - Method of forming signal for controlling electroacoustic emitter - Google Patents

Abstract

FIELD: radio, communication.

SUBSTANCE: method comprises applying voltage to the signal emitter, representing the sum of the traditional voltage signal proportional to the value of the desired acoustic pressure and the additional voltage signal obtained by the formula Ud(t)=k·(a0·p(t)'+a1·p(t)''), where p(t) is the acoustic pressure, which is necessary to create, p(t)', p(t)'' is the first and the second derivative of pressure in time, k is the coefficient that determines the volume level, a0, a1 are the constants in the formula, having the values at which the rate of increase and decrease of signals of acoustic pressure when creating by the electroacoustic emitter of test signals is as close as possible to the rate of increase and decrease of test signals, and the waveforms of acoustic pressure has the least distortions.

EFFECT: reduction in the amount of signal distortion.

6 cl, 2 dwg

Description

The invention relates to the field of radio engineering, and in particular to methods for reducing the distortion of the shape of the acoustic signal of the speaker relative to the shape of the signal that you want to play.

A known system and method for compensating inertialess nonlinear distortion in an audio converter (Patent RU 2440692 C2, IPC H04R 3/00, H04R 29/00, published: 01/20/2012).

The audio playback system estimates the amplitude and speed of the signal, finds the scale factor from the lookup table (LUT) for a given pair of amplitude, speed (or calculates the scale factor for polynomial approximation to the LUT) and applies the scale factor to the signal amplitude. The scale factor is an estimate of the inertialess nonlinear distortion of the transducer at a point on the phase plane specified by amplitude, velocity, which is found by applying a test signal having a known amplitude and velocity of the signal to the transducer, measuring the amplitude of the recorded signal and setting the scale factor equal to the ratio of the amplitude of the test signal to the amplitude of the recorded signal. Scaling can be used to pre- or post-compensate for an audio signal depending on the audio converter. The proposed solution provides real-time compensation of inertialess nonlinear distortion in the audio transducer and is inexpensive.

The disadvantage of this invention is that the system does not compensate for all interference.

The closest analogue adopted for the prototype of the present invention is a method of reducing distortion of the sound signal of the speaker, which consists in supplying an incoming electrical signal to the input of the speaker and converting it into an acoustic signal, characterized in that the speaker is operated in setup mode and in operating mode, the speaker being in setup mode they test for a limited amount of distortion by converting the distortion of the audio signal at the output of the speaker into an electric signal and record the test results, and in the operating mode, a computer is connected to the loudspeaker, into which the recorded test results are preliminarily entered, changing these results to the opposite, and they are summed with the incoming electrical signal, converting into a correction signal, and then the received signal, depending from the parameters of the incoming electrical signal, the correction signal to the loudspeaker. The described method allows to improve the quality of reproduction of the audio signal by reducing the level of any distortion arising in the loudspeaker during its operation (Patent RU No. 2161379, IPC ⁷ H04R 9/00, G10K 11/00 from 06/01/2000).

The analogue described above in some way solves the problem of reducing distortion of sound reproducing devices only from a limited number of distortions arising in the loudspeaker. In practice, it is not possible to record all distortions that occur on the speaker, so the speakers can be tested for a limited number of characteristic distortions that have the greatest impact on the quality of the reproduced sound. As it is written in the description, that the more the test results recorded in the form of electrical signals are entered into the computer's memory, the higher the sound quality of the loudspeaker.

The objective of the proposed solution is to eliminate the distortion of the acoustic signal of the electro-acoustic emitter associated with its not ideal, expressed in the insufficient rate of rise and decay and receiving an acoustic signal of any shape more similar to the sound image signal (the acoustic signal that we want to reproduce) within the operating range amplitude and frequency of the acoustic emitter.

The problem is solved using the method of generating a control signal of an electro-acoustic emitter, with its acoustic design, to better recreate the shape of the acoustic signal, within the operating range of the amplitude and frequency of the electro-acoustic emitter, at a given distance along the axis of the emitter, including the operation of the emitter in test mode and operating mode and applying voltage to the emitter.

A voltage signal is applied to the emitter

U (t) = Utr (t) + Ud (t) = k * (p (t) + a 0 * p (t) '+ a 1 * p (t)''), where

Utr (t) is a traditional voltage signal proportional to the value of the desired acoustic pressure

Utr (t) = kp (t),

Ud (t) is an additional voltage signal obtained according to the formula

Ud (t) = k · ( a 0 · p (t) '+ a 1 · p (t)''),

where p (t) is the acoustic pressure that you want to reproduce,

p (t) ', p (t)' 'the first and second time derivatives of pressure,

k is a coefficient that determines the volume level,

a 0, a 1 - constants in the formula, have values at which the rise and fall rates of the acoustic pressure signals when the test signals are reproduced by the electro-acoustic emitter, which are within the operating frequency range of the emitter, will be as close as possible to the rise and fall rates of the test signals, and the acoustic pressure waveform will have the least distortion.

Preferably, an additional voltage signal is supplied to the input of an individual electro-acoustic emitter.

Preferably, an additional voltage signal is supplied to the input of a serial electro-acoustic emitter.

Preferably, the source and converted signals are filtered on high and low pass filters so that the signal supplied to the emitter is within the operating frequency range of the emitter.

Preferably, the values of the constants a 0, a 1 are chosen such that the reproduction of acoustic pressure p (t) most fully meets one's taste or desire.

Preferably, a sequence of rectangular pulses or single sines is supplied as test signals.

On the way to solving this issue, manufacturers of electro-acoustic emitters reduce the mass of the mobile system to the maximum. The mass of the mobile system, if it consists of some parts, to make with zero weight is unrealistic. Many electro-acoustic emitters are an inductive load for an amplifier, but the magnitude of the inductance, which also significantly affects the rate of rise and fall of an acoustic signal, cannot be reduced to zero or close to it, because this will not allow the emitter to move - the force will be zero. The invention makes it possible to more reliably and accurately reproduce music, sounds and any other acoustic signals.

When recording, transmitting and reproducing music and speech signals through audio equipment, distortions of the temporal structure of the signal occur, which can be divided into linear and non-linear.

Linear distortions change the amplitude and phase relationships between the available spectral components of the input signal and thereby distort its temporal structure. Such distortions are subjectively perceived as distortions of the signal timbre, and therefore, problems of their reduction and subjective assessments of their level receive much attention from specialists throughout the entire period of development of sound engineering.

The requirement for the absence of linear distortion of the signal in the audio equipment can be written in the form:

$$y(t)=k\cdot x(t-T),\text{(one)}$$

where x (t) is the input signal, y (t) is the output signal.

This condition allows only a change in the signal on a scale with a coefficient k and its time shift by T. It determines the linear relationship between the input and output signals.

Consider examples with an electro-acoustic emitter having the mass of a mobile system and inductance. Such a radiator is, for example, a dynamic sound head - DZG.

Let the acoustic signal be equal to zero until time t0. From time t0, an electrical voltage signal is applied to the dynamic sound head - DZG

$$U(t)=k\cdot p(t),\text{(2)}$$

where p (t) is the acoustic pressure that you want to create,

k is a coefficient that determines the volume level.

The sound pressure pa (t, R), which is then emitted by the DGG at a given distance R from the emitter along its axis, is not proportional to p (t). This is because at every moment of time the energy supplied to the DGG goes not only to radiation, because there is a continuous flow of energy. As a result, only the shape of the envelope amplitudes of the quantities pa (t, R) and p (t) have some similarities.

The mobile system of the electro-acoustic emitter, as a rule, has a certain mass. The larger the mass, the more kinetic energy it stores and the more difficult it is to accelerate or slow it down to create the corresponding sound pressure, and this leads to a significant difference in the shape of the reproduced acoustic signal from the waveform supplied to the DZG, which is typical for inertial electroacoustic transducers.

If we apply a signal (Fig. 1) to a DZG emitter in the form of a train of 10 sine periods, we will see that the speaker system will produce an acoustic signal different from the voltage applied to the input of Fig. 1a and similar to the signal shown in Fig. 1b.

In the initial section - a) the amplitude of the emitted signal will increase. In order to emit an acoustic signal with a steady amplitude A0, the mobile system of the emitter must have a certain amount of energy. Initially, before the signal arrived, its total energy was zero. When a signal is supplied to the emitter, the energy supplied to the emitter goes to the energy storage in the mobile system and its absorption (goes to acoustic radiation and heat). The amount of absorbed energy increases with increasing amplitude of the oscillations of the mobile system of the acoustic emitter and, finally, when the amplitude of the emitted acoustic signal is close to A0, it is practically compared with the energy supplied to the emitter, and the energy of the mobile system practically ceases to increase.

In the middle section - b) the amplitude of the emitted signal will be almost constant (in fact, there is a close to exponential dependence of the approximation of the amplitude to the value A0). With sufficient accuracy, the amplitude of the emitted acoustic signal is constant and equal to A0. The energy of the mobile system is constant. The flow of energy entering the emitter is almost equal to the flow of absorbed energy.

In the final section - c) after the end of the sinusoidal signal, the acoustic signal has a continuation, the character of which is determined by the properties of the oscillatory system of the head and is practically independent of the exciting signal. The duration of the establishment process depends on the energy stored in the mobile system and its absorption rate.

Those. when acoustic signals are not stationary, then acoustic emitters capable of storing and delivering energy will always have differences in the shape of the acoustic signal emitted by them (sound pressure value) from the shape of the input signal (voltage applied directly to the emitter).

To create the desired acoustic pressure p (t), voltage is traditionally applied to the electro-acoustic emitter

Utr (t) = kp (t),

where k is a coefficient that determines the volume level.

If the emitter represented an infinite plane without mass, making motions as a unit along its normal, and its mover, in the direction of the normal, created a driving force of magnitude proportional to the magnitude of the applied voltage, then a plane wave with acoustic pressure would be created in the medium proportional to p (t).

A real emitter, for example, a DZG, has finite dimensions, a moving system having mass, its mover has active resistance, inductance, the strength of the current flowing through it differs in form from changes in the voltage applied to its input.

Instead of applying a voltage Utr (t) = k · p (t), we give a signal of the form

$$U(t)=k\cdot (p(t)+a0\cdot p(t)\text{'}\text{'}+a\mathrm{one}\cdot p(t)\text{'}\text{'}\text{'}\text{'}),\text{(3)}$$

where p (t) is the acoustic pressure that you want to create,

p (t) ', p (t)' '- the first and second time derivative of pressure,

k is a coefficient that determines the volume level,

and 0, a 1 - constants, depending on the physical parameters of the electro-acoustic emitter, namely: mass, inductance and coefficient of electromechanical coupling of the mobile system and some other physical parameters of the electro-acoustic emitter.

Signal

$$Ud(t)=k\cdot (a0\cdot p(t)\text{'}\text{'}+a\mathrm{one}\cdot p(t)\text{'}\text{'}\text{'}\text{'}),\text{(four)}$$

and there is an additional voltage signal, which is supplied in addition to the traditionally applied signal

Utr (t) = kp (t).

The supply of an additional signal Ud (t) makes it possible to increase the rate of rise, fall, and attenuation of the acoustic signal when reproducing the acoustic pressure p (t) to better recreate its shape, within the limits of the working range of the amplitude and frequencies of the electro-acoustic emitter.

The values of the constants a 0, a 1 for a particular electro-acoustic emitter, for example, DZG, can be determined by varying the values of the constants a 0, a 1 and applying test signals within the operating range of the amplitude and frequency of the emitter, fixing those values of the constants for which the form of reproduction test signals that are emitted by the DZG at a given distance R from the emitter along its axis will be the best (the criterion of greatest reliability) or the most suitable for the taste of a particular user (comfort criterion vuchaniya). When using the criterion of the highest reliability for reproducing acoustic signals, it is easier to find the values of the constants a 0, a 1, if simple signals are applied to the DGS - such as a sequence of rectangular pulses or a sequence of single sines.

Below is an example of conducting test tests to determine the constants a 0, a 1 for a specific acoustic emitter operating in the frequency band from fmax to fmin.

In accordance with the foregoing, for this we use a rectangular test signal pr (t), which is preliminarily passed through a high-pass filter and a low-pass filter so that the spectrum of the filtered signal fpr (t) falls in the region from fmax to fmin, i.e. . was within the operating frequency range of the acoustic emitter. The function fpr (t) has the form of a signal, which in the ideal case should reproduce an electro-acoustic emitter within its operating frequency range when reproducing the signal pr (t).

Give a voltage signal to the acoustic emitter

U (t) = kfpr (t), where

k is a coefficient that determines the volume level,

fpr (t) - filtered out in the range from fmax to fmin the signal of the sequence of rectangular pulses pr (t).

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = kfpr (t).

We call it Pa (t, 0, 0).

BUT.

Definition of the constant a 0.

First, we first determine the value of the constant a 0 in formula (3), taking the value of the constant a 1 = 0.

To do this, in accordance with formula (3), we apply a voltage signal to the acoustic emitter

U (t) = k (fpr (t) + a 0fpr (t) ') + 0fpr (t)') = k (fpr (t) + a 0fpr (t) '),

Where

k is a coefficient that determines the volume level,

fpr (t) - filtered signal in the range from fmax to fmin a sequence of rectangular pulses pr (t),

fpr (t) 'is the first time derivative of the signal fpr (t),

a 0 = 2004 - arbitrary value of the constant

a 1 = 0 - an arbitrary value of the constant chosen by us.

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k (fpr (t) + 2004fpr (t) ').

We call it Pa (t, 2004.0).

1. If the signal Pa (t, 2004, 0) is very similar to Pa (t, 0, 0), then the value of a 0 = 2004 is too small, and we must increase the value of a 0 to the value of a 01 when we we will see a slight difference in the phase, shape and amplitude of the signals

Pa (t, a 01, 0) and Pa (t, 0, 0).

We remember the reproduced acoustic signal obtained when a voltage signal with the selected constant a 0 = a 01 is applied to the acoustic emitter

U (t) = k (fpr (t) + a 01fpr (t) ').

We call it Pa (t, a 01, 0).

If the signal Pa (t, 2004, 0) is very different from Pa (t, 0, 0), then the value of a 0 = 2004 is too large, and we must reduce the value of a 0 to the value of a 01 when we visually see a small difference in phase, shape and amplitude of signals

Pa (t, a 01, 0) and Pa (t, 0, 0).

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k (fpr (t) + a 01fpr (t) ').

We call it Pa (t, a 01, 0).

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k · (fpr (t) - a 01 · fpr (t) ').

We call it Pa (t, - a 01, 0).

2. Compare the shape of the three signals: Pa (t, a 01, 0), Pa (t, - a 01, 0) and Pa (t, 0, 0).

Regarding the signal Pa (t, 0, 0), one of them will have more gentle edges of the signal, the other will be steeper.

If the steeper rise front of the reproduced acoustic signal with a positive value of a 0, then its value is positive.

If the steeper rise front of the reproduced acoustic signal with a negative value of a 0, then its value is negative.

3. Having determined the sign + or - of the quantity a 0, we conduct a more accurate determination of its absolute value (modulo) - | a 0 |.

Start to increase | a 0 |. Initially, the reproduced acoustic signal Pa (t, a 0, 0) increases the slope of the signal edge. Then, in the region of the signal fronts, distortions begin to appear in the form of an additional peak. Those. first, the waveform Pa (t, a 0, 0), with increasing a 0 in absolute value from | a 0 | = 0 to a 0 = A0, approaches in shape to the waveform fpr (t), then, with a further increase | a 0 | the edges of the signal Pa (t, a 0, 0) acquire the steepness of the edges and distortions up to additional peaks at the edges of the signals, which are unusual for the signal fpr (t). We remember the value a 0 = A0.

At the first stage, we determined with some accuracy the value a 0: a 0 = A0.

B.

Definition of the constant a 1.

At stage B, we determine the value of the constant a 1 with the value a 0 = A0 found above, with some accuracy.

To do this, in accordance with formula (3), we apply a voltage signal to the acoustic emitter

U (t) = k (fpr (t) + A0fpr (t) '+ a 1fpr (t)''),

Where

k is a coefficient that determines the volume level,

fpr (t) - filtered signal in the range from fmax to fmin a sequence of rectangular pulses pr (t),

fpr (t) 'is the first time derivative of the signal fpr (t),

fpr (t) '' is the second time derivative of the signal fpr (t),

a 0 = A0,

a 1 = 2006 is an arbitrary value of the constant chosen by us.

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k (fpr (t) + A0fpr (t) '+ 2006fpr (t)' ').

We call it Pa (t, A0, 2006).

1. If the signal Pa (t, A0, 2006) is very similar to Pa (t, A0, 0), then the value of a 1 = 2006 is too small, increase the value of a 1 to the value of a 11 when we see a slight phase difference , shapes and amplitudes of the signals Pa (t, A0, a 11) and Pa (t, A0, 0).

We remember the reproduced acoustic signal received when a voltage signal is applied to the AI

U (t) = k (fpr (t) + A0fpr (t) '+ a 11fpr (t)').

We call it Pa (t, A0, a 11).

If the signal Pa (t, A0, 2006) is very different from Pa (t, A0, 0), then the value of a 1 = 2006 is too large, we reduce the value of a 1 to the value of a 11 when we see a slight difference in phase, shape and the amplitudes of the signals Pa (t, A0, a 11) and Pa (t, A0, 0).

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k (fpr (t) + A0fpr (t) '+ a 11fpr (t)'').

We call it Pa (t, A0, a 11).

We remember the reproduced acoustic signal received when a voltage signal is applied to the acoustic emitter

U (t) = k (fpr (t) + A0fpr (t) '- a 11fpr (t)'').

We call it Pa (t, A0, - a 11).

2. Compare the shape of the three signals: Pa (t, A0, a 11), Pa (t, A0, - a 11) and Pa (t, A0, 0).

Regarding the signal Pa (t, A0, 0), one of them will have more gentle edges of the signal, the other will be steeper.

If the steeper rise front of the reproduced acoustic signal with a positive value of a 1, then its value is positive.

If the steeper rise front of the reproduced acoustic signal with a negative value of a 1, then its value is negative.

3. Having determined the + or - sign of the quantity a 1, we more accurately determine its absolute value (modulo) - | a 1 |.

Start to increase | a 1 |. Initially, the reproduced acoustic signal Pa (t, A0, a 1) increases the slope of the signal front. Then, distortions begin to appear in the region of the signal fronts. Those. first, the waveform Pa (t, A0, a 1), with increasing a 1 in absolute value from | a 1 | = 0 to a 1 = A1, approaches in form to the waveform fpr (t), then, with a further increase | a 1 |, the edges of the signal Pa (t, A0, a 1) acquire an unusual signal fpr (t) shape near the edges and distortions until additional peaks appear on the signal edges. We remember the value of the constant a 1 = A1.

FROM.

Clarification of the value of the constants a 0, a 1.

At stages A and B, in a first approximation, we determined the values of the constants a 0, a 1. Now, we can refine their value by varying their value near the values of A0, A1, achieving greater similarity of the reproduced acoustic signal Pa (t, a 0, a 1 ) on fpr (t). Thus, we find the updated values of the constants a 0, a 1 for the most accurate reproduction of the sound signal by the acoustic emitter. We call these values A0, A1, respectively, for a 0, a 1.

The sequence of finding the coefficients in their selection, in the above in paragraphs A, B, C method, does not matter. You can first find the value of a 0 with a 1 = 0 and then find the value of the constant a 1, as done above, but you can first find the value of a 1 with a 0 = 0 and then find the value of the constant a 0.

D.

For better reproduction of the acoustic signal, it is required that the signal supplied to the acoustic emitter

U (t) = k (fpr (t) + A0fpr (t) '+ A1fpr (t)' '),

fell into the region from fmax to fmin, i.e. was within the operating frequency range of the acoustic emitter.

Each acoustic emitter with its acoustic design has its own coefficients in the formula (4) of the dependence of Ud (t) on p (t). If the repeatability of the physical parameters of the electro-acoustic emitter and its acoustic design is high enough, then you can find the values of the coefficients a 0, a 1 once for all such electro-acoustic emitters. The formula for the dependence of Ud (t) on p (t) for a particular electro-acoustic emitter, for example, DZG, with its acoustic design, we put in a counting device that will work with this emitter.

Auditory tastes in people are different and quite subjective, therefore, a signal source with adjustments to the values of a 0, a 1 will quite realistically be in demand. There is the possibility of a wide range of adjustments (adjustments in a 0, a 1) from the most reliable, when a 0 = A0, a 1 = A1, to any more unreliable reproduction, up to the traditional way of applying a signal to an acoustic emitter, when a 0, a 1 are equal to zero. Indeed, substituting in the expression (3) a 0 = 0, a 1 = 0

U (t) = kP (p (t) + a 0P (t) '+ a 1P (t)'') = kP (p (t) + 0P (t)' + 0 P (t) ''),

we get

U (t) = kp (t).

This is the traditional way of applying a signal to an acoustic emitter.

Let us need to reproduce with an electro-acoustic emitter with known constants a 0, a 1, for example, DZG, with its acoustic design, the acoustic pressure proportional to the signal p (t) within the limits of the working range of the emitter’s amplitude and frequencies and recorded, for example, on a compact disc.

1. Read the signal from the disk.

2. We pass the signal through the filter of allowed frequencies and get fp (t).

3. We send a signal to the counting device, where according to the signal conversion formula (3) we calculate the voltage value U (fp (t)), which should be fed to the input of the electro-acoustic emitter.

4. Convert the value of the voltage U (fp (t)) into an electrical signal.

5. We apply an electric signal to the electro-acoustic emitter, which creates acoustic pressure.

The invention allows for significantly more reliable reproduction by an acoustic emitter, for example, DZG, of the shape of any acoustic signal than it was before the application of this invention. Since the magnitude of the signal supplied to the acoustic emitter is calculated by the formula, the proposed method, in contrast to the prototype, solves the problem of reducing distortions associated with the insufficient rate of rise, fall, and attenuation of acoustic signals when any signals are supplied to the acoustic emitters within the limits of the working amplitude range and frequencies.

As an example, we consider in figure 2 the real signals reproduced by the DZG in a non-damped room without using the proposed invention and with it.

On figa shows the signal that you want to reproduce - a sequence of single sines.

In Fig.2b, an acoustic signal that reproduces the DZG when a signal from Fig.2a is fed to its input and is previously passed through the filter of allowed frequencies. Significant differences in the amplitude and phase of the reproduced signal are visible, the attenuation of the acoustic signal after the cessation of the electrical signal is slower than in the case of fig.2c.

In Fig. 2c, an acoustic signal that produces a DZG when a signal calculated on a counting device is applied to the input, where the voltage U (t) is calculated by the signal conversion formula, which should be applied to the input of an electro-acoustic emitter according to the invention. You can see a significant improvement in signal reproduction quality when using the invention, in particular, faster signal growth and faster signal attenuation, it can be seen that the signals of FIG. 2a and FIG. 2c are substantially more similar in shape than the signals of FIG. 2a and 2b.

The technical result of the invention is to reduce the distortion of the acoustic signal of the emitter associated with its not ideal, expressed in insufficient speed of rise, fall and decay of the reproduced acoustic signal. Using the invention allows you to recreate an acoustic signal of any shape with greater similarity to the signal of the sound image within the boundaries of the working range of the amplitude and frequency of the acoustic emitter.

Claims (6)

1. A method of generating a control signal for an electro-acoustic emitter, with its acoustic design, to better recreate the shape of the acoustic signal, within the boundaries of the working range of the amplitude and frequencies of the electro-acoustic emitter, at a given distance along the axis of the emitter, including the operation of the emitter in test mode and operating mode and applying voltage to a radiator, characterized in that a voltage signal is supplied to the radiator
U (t) = Utr (t) + Ud (t) = k · (p (t) + a 0 · p (t) '+ a 1 · p (t)'),
Where
Utr (t) is a traditional voltage signal proportional to the value of the desired acoustic pressure
Utr (t) = kp (t),
Ud (t) is an additional voltage signal obtained according to the formula
Ud (t) = k · ( a 0 · p (t) '+ a 1 · p (t)''),
p (t) is the acoustic pressure that you want to reproduce,
p (t) ', p (t)''- the first and second time derivative of pressure,
k is a coefficient that determines the volume level,
a 0, a 1 - constants in the formula, have values at which the rise and fall rates of the acoustic pressure signals when the electroacoustic emitter reproduces test signals that are within the operating frequency range of the emitter, is as close as possible to the rise and fall rates of the test signals, and the form acoustic pressure signals have the least distortion. 2. The method according to claim 1, characterized in that the additional voltage signal is fed to the input of an individual electro-acoustic emitter. 3. The method according to claim 1, characterized in that the additional voltage signal is fed to the input of a serial electro-acoustic emitter. 4. The method according to claim 1, characterized in that the source and converted signals are filtered on the high and low frequency filters so that the signal supplied to the emitter is within the limits of the operating frequency range of the emitter. 5. The method according to claim 1, characterized in that the values of the constants a 0, a 1 are chosen such that the reproduction of acoustic pressure p (t) most fully meets one's taste or desire. 6. The method according to any one of claims 1 to 5, characterized in that a sequence of rectangular pulses or single sines is supplied as test signals.

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