EP0508392A2 - Circuit arrangement for correcting linear and non-linear transfer characteristics of electroacustic transducers - Google Patents

Abstract

The invention relates to a circuit arrangement for correcting linear and non-linear transfer characteristics of electroacoustic transducers within the entire range of modulation (small- and large-signal behaviour), consisting of an electrical equaliser network which is coupled to the connecting terminals of the transducer and an aid, which is connected either temporarily or continuously, for matching the equaliser network to the transducer. The equaliser network (1) consists of a chain circuit of transmission elements, at least one transmission element (two-terminal network Z) exhibiting a non-linear transfer characteristic between its input and output port. The non-linear equaliser network contains linear transmission systems, multiplicative and additive logic elements and non-linear volatile two-terminal networks which are interconnected in accordance with the balanced active structure of the transducer. The parameters of the non-linear volatile two-terminal networks are variable by means of control signals (39, 40, 41). The matching aid activated only for matching purposes contains a main controller (89), a generating part (75) for generating an excitation signal and an analysis part (76) for converting the measurement signal, picked up via a sensor (3), into control signals (39, 40, 41) for automatically setting the parameters of the equaliser network. The equaliser network matched to the transducer (2) by means of this aid changes the linear transfer characteristics and reduces the non-linear distortions of the overall system. The invention is characterised most clearly by Figure 22. <IMAGE>

Description

The invention relates to an arrangement for correcting the linear and non-linear transmission behavior of electroacoustic transducers, consisting of an electroacoustic transducer, an electrical equalizer network coupled to the electrical input terminals and an aid for adapting the equalizer network to the transducer. The electrical network has a non-linear transmission behavior and changes the electrical signal in such a way that the non-linear effects of the network and the coupled converter are compensated for. In this way, an overall system with reduced nonlinear distortion and improved linear transmission behavior can be implemented. With the help of an adaptation method and an arrangement, the parameters of the electrical network can be changed and independently adapted to the specific transmission behavior of the converter.

The causes of the nonlinear distortions in electroacoustic transducers are very different and depend on the transducer principle used in each case.

In the case of electrodynamic converters (loudspeakers, headphones, microphones, technical actuators), the displacement-dependent parameter changes cause the strongest nonlinear distortions. In loudspeaker arrangements with special sound guidance, additional distortions occur in the pressure chamber and in the horn entrance due to non-linear compression and flow processes. Even with electrostatic converters (condenser microphones), the redistribution (or migration) of the electrical charges disrupts the linear transmission behavior.

The reduction in nonlinear signal distortion results to improve the subjective auditory impression in electroacoustic recording and playback of audio signals. But also in measurement technology and active noise abatement, there are sometimes considerable demands on the linearity of sensors and actuators. Non-linear distortions that occur in the anti-noise system are not compensated for by the noise and limit the effectiveness of the noise protection measure. A linearization of sound transmitters with constructive means generally leads to a reduction in efficiency and leads to increased additional expenditure for practical sound reinforcement tasks. Therefore, attempts are made to equalize the converter by means of additional electrical systems and to improve its linear and non-linear transmission behavior.

For this purpose, negative feedback was proposed in GB Patent 1,031,145 (PH 18,481) for electroacoustic sound transmitters. For this purpose, an electrical, mechanical or acoustic variable is measured on the transducer or in the surrounding sound field and converted into a variable (current or voltage) equivalent to the drive signal and added to the feed signal in the opposite phase, i.e. negative feedback.

The negative feedback has the advantage that the exact structure of the nonlinear transmission system does not have to be known and that the functionality is retained when the nonlinearity (aging) changes. However, the required signal pickups are expensive, susceptible and have a specific transmission behavior that must be compensated for by suitable equalizer networks. The danger of a possible positive feedback requires measures to correct the phase response ([1] Hall, DS: Design Considerations for an Accelerometer-Based Dynamic Loudspeaker Motional Feedback System. 87. Audio Eng. Soc. Conv, New York October 1989 (Preprint 2863)) . All these problems prevent the negative feedback on electroacoustic sound transmitters from becoming widely accepted.

In terms of practical implementation, it is advantageous to basically do without the signal pick-up on the converter and to realize a purely serial predistortion without signal feedback.

For this it is first necessary to model the non-linear transmission behavior of the converter with sufficient accuracy and to describe it using a non-linear transfer function. If the converter is now preceded by a dynamic nonlinear system which simulates the inverse nonlinear transfer function of the converter with sufficient accuracy, the overall distortions can be compensated for.

The VOLTERRA series development offers a possible starting point for modeling the non-linear converter. It is a very advantageous hand tool for describing second and third order distortions of weakly nonlinear systems with very small input signals. In the case of stronger non-linearities, the system can no longer be described by quadratic and cubic subsystems, and other elements of the VOLTERRA series must be taken into account. In order to achieve convergence, the input signal must always be sufficiently small and limited according to the Weierstrass criterion. This theory was first applied to the converter by ([2] Kaizer, A.J .: Modeling of the Nonlinear Response of an Electrodynamic Loudspeaker by a Volterra Series Expansion. J. Audio Eng. Soc. 35 (1987) 6, p. 421). In the small-signal behavior, a good agreement between the measured and calculated distortions was achieved, but nonlinear effects can be observed with larger modulations, which cannot be described with quadratic and cubic transfer functions ([3] Klippel, W .: The Large-Signal-Behavior of Electro -dynamical Loudspeakers at Low Frequencies. 90th AES Convention Paris 1991, Preprint 3049).

If the VOLTERRA functionals of any causal, time-invariant, non-linear system are known, then according to ([4] Butterweck, HJ: Frequency-dependent non-linear transmission systems. Archive Electronics and Transmission Technology, Volume 21 (1967), Volume 5, p. 239) Compensation system can be derived with the inverse transfer function. Kaizer applied this method to the electrodynamic converter and proposed in EP 85200885 an "arrangement for converting an electrical signal into an acoustic signal and vice versa when using a non-linear network", which is intended to reduce the linear and non-linear distortions. This arrangement "contains at least two parallel branches, the first branch compensating for the first-order distortions ... and the other branch compensating for the higher-order distortions". This arrangement has a consistently additive structure corresponding to the series properties of the VOLTERRA development. The individual branches represent higher order linear, quadratic, cubic or nonlinear networks and compensate for the corresponding distortion products. Unfortunately, this concept only insufficiently takes into account the transducer-specific features and, in practical implementation, requires a restriction to square and cubic correction systems. Although it is possible to successfully compensate for distortion in the small signal range, the converter no longer behaves like an ideal quadratic or cubic system with a larger input signal and the inevitable incorrect compensation leads instead to a reduction in an increase in the distortion in the transmission signal. The insertion of higher order compensation elements extends the usable modulation range, but does not fundamentally solve the problem and leads to technically hardly realizable equalization systems. The additive parallel structure of the equalizer network, which inevitably results from the VOLTERRA modeling, leads to a universal but complex circuit structure, which has decisive disadvantages in large signal behavior.

The problem of adapting nonlinear equalizer networks to the electroacoustic transducer has not been discussed in the literature and no methods, tools or automatic methods have been developed to date.

The object of the invention is, for the first time, to create an equalizer network without constant signal feedback (motional feed back), which completely , automatically (independently) compensates for the nonlinear distortions in the small and large signal range (up to the maximum power loss or in the entire deflection range of the voice coil) allows the specific peculiarities (non-linear causes of distortion) of the respective electroacoustic transducer to be better taken into account and implemented with less effort.

According to the invention, the electroacoustic sound transducer is described by an electro-mechano-acoustic equivalent circuit diagram. Here, the structural components of the converter that are essential for signal transmission are functionally combined in concentrated active elements, each of which is characterized by a parameter (for example damping, rigidity of the suspension, electrodynamic coupling factor B1, etc.). In addition to the moving mass m of the voice coil and the membrane, all other elements of the transducer system are subject to temporal parameter changes. The changes caused by aging, fatigue and warming prove to be long-term processes that change the linear transmission properties of the converter, but do not cause non-linear signal distortions. The parameter changes caused by the state variables deflection, current, fast, voltage and sound pressure lead to the known nonlinear distortions in the transmitted signal. The transmission behavior is fully described with a non-linear integro differential equation (IDG), from which the associated equalizer transfer function is derived by conversion and transferred directly into the circuit structure of the equalizer network.

This results in the circuit structure, which takes into account the physical peculiarities of the respective electroacoustic transducer system and allows full compensation of the nonlinear distortions.

For better understanding, the steps necessary to solve the task can also be explained with the help of signal flow plans.

This should be illustrated using the example of the electrodynamic woofer in voltage supply.

The electromechanical equivalent circuit diagram (FIG. 7a) can be transferred with the aid of the associated nonlinear IDG into an equivalent signal flow diagram (FIG. 7b) which consists of a nonlinear transmission system (152) and a subsequent linear transmission system (153). The linear subsystem (153) is composed of an electro-mechanical system (144) with the transfer function X (s) and a downstream mechano-acoustic system with the transfer function H (s).

The non-linear system (152) connected upstream of the linear transmission system (153) causes the disturbing, non-linear signal distortions.

The nonlinear system (152) contains nonlinear, dynamic transmission systems (two-port 147-151) and a linear transmission system (two-port 167), which also has the transfer function X (s) and further linking elements (139-143, 145).

The linear and non-linear transmission systems have one input and one signal output, the logic elements have two signal inputs and one signal output. The output of each transmission system is connected to the one input of a logic element. Both parts are referred to below as a three port. Each three port represents exactly one non-linear cause of distortion.

The three gates, which represent the deflection-dependent induction, the deflection-dependent damping, the electromagnetic drive and the deflection-dependent stiffness, contain adders (139, 141, 142, 143) as logic elements. Surprisingly, the deflection-dependent, electrodynamic drive leads to a multiplicative one Linking element (140). The three port, which describes the Doppler distortions, contains a variable delay element (145) as the link element.

All three gates are interconnected in a certain structure. In this case, the output of the preceding logic element is linked to an input of the next logic element and leads to a chaining of all three-port gates contained. The three-port (147,139), which describes electrical induction, comes first, followed by the three-port of the electrodynamic force factor (148, 140) and the three-port, which are connected to the electromagnetic drive (150, 142), the non-linear damping (141 , 149) and the stiffness (143, 151) correspond. In the last position immediately in front of the linear subsystem (145, 146) is the three port (145, 167), which corresponds to the generation of the Doppler distortions in the acoustic system. The inputs of all non-linear subsystems and of the linear transmission system (167) are connected to the signal input of the delay element (145). The transmission systems (147-151) are thus fed back without feedback via a signal feedback and the three port of the Doppler distortions. The well-known large signal effects (amplitude compression, phase shift of the fundamental oscillation and the distortion products) result from the signal feedback in the electromechanical converter part. The Doppler distortions caused by the Dreitor (145, 167) do not influence the mechanical vibration behavior (deflection of the membrane) and thus the process of creating the nonlinear distortions. Due to the different supply of the transmission systems (retroactive, non-reactive), the non-linear transmission system (152) consists of two non-linear subsystems connected in series.

The effect of this nonlinear transmission system (152), ie the occurrence of disturbing nonlinear distortions in the output signal, can be completely compensated for by a very specific equalization system, that of the sound transmitter upstream:
According to the invention, this goal is achieved in that the equalization system the transmission elements S _L (166), S _B (165), S _D (164), S _M (163), S _S (162) and X (s) (161 ) contains, which correspond to the nonlinear and linear transmission systems of the converter (147 - 151, 167) in their transmission behavior. Each of these transmission elements is connected to a logic element that has exactly the inverse properties of the logic element in the corresponding converter driver, ie instead of the adders (139, 141-143), subtractors (156-158, 160) result instead of the multiplier (140) Division element (159) and the controllable delay element (145) leads to a delay element with the opposite control characteristic. The connection of the transmission link and associated link element is referred to below as a three port.

All three gates in the equalizer network are connected in a chain in exactly the right order (in relation to the input terminals of the converter) using one of their inputs and their outputs. The input of all transmission elements (two-port 161-166), i.e. the other input of the three-port is connected to the output of the delay element. The three-port of the Doppler distortions in the converter signal flow diagram (145, 167) fed without feedback corresponds to an equalizer three-way (155, 161) which has a signal feedback. The other three-port electromechanical gates, which were connected via a signal feedback in the converter signal flow diagram, correspond to three-port gates in the equalizer network that are switched without feedback. The equalizer network thus also consists of two non-linear subsystems connected in series.

Only with this filter structure of the equalizer, which was derived by inverting and mirroring the converter system structure, do the three-ports in the converter and equalizer network fully compensate, i.e. the addition (139) is achieved by subtracting (160) the same signal in Equalizer compensated, the multiplication (140) is compensated for by the division element (159) with the same signal in the equalizer. All other elements of the interference system are compensated in the same way by the mirrored connection of the inverse logic elements.

This results in a clearly assignable circuit structure of the equalization network for each type of electroacoustic transducer.

The following general features are common to all these circuit structures:
The equalizer network consists of a chain connection (series connection) of transmission elements, with at least one transmission element (two-port) having a non-linear transmission behavior between its input and output ports.

Surprisingly, it was found that a complete compensation of certain, simultaneously acting, non-linear causes of distortion (e.g. Doppler distortion and force factor in the woofer or force factor and damping in the electrodynamic microphone) is only possible through a serial connection (series connection) of several non-linear transmission elements (see Fig. 1 ).

A chain connection of the transmission links of the equalization network means that the links are mutually linked with their input and output and are thus switched on in the transmission chain (sound receiver, signal memory, transmitter, receiver, amplifier, sound transmitter). Each of these nonlinear transmission elements (two-port Z₁, Z₂, Z₃) is a memoryless (frequency-independent) or dynamic (frequency-dependent) system.

Each dynamic, non-linear two-port Z contains at least one transmission three (see FIG. 2), which corresponds to a non-linear cause of distortion in the converter and serves to compensate for the corresponding non-linear distortions.

Each three-port D in turn is a dynamic, non-linear one Transmission link with two signal inputs E₁, E₂ and an output A (see. Fig. 3). It consists of a non-linear, dynamic transmission element (two-port U) and a memory-less logic element V, which converts the two input signals into the output signal via an algebraic operation (eg addition, multiplication). One input E₁ of the Dreitor D is connected directly to one input of the logic element, the other input E₂ of the Dreitor (D) is connected via the two-port U to the second input of the logic element and the output of the logic element is connected to the output of the Dreitor ( D) coupled. The two-port U takes into account the physical properties of the variable converter parameter and its position in the active structure of the converter. If several transmission three gates are arranged between the input and output of the two gates (Z) (Fig. 2), these are connected in a chain connection using the respective input gate E 1 (18) and the output gate A (20) and the remaining input gate E 2 ( 19) of the three gates contained either connected to the input gate of the two-port Z (FIG. 2 a) or to the output port of the two-port Z (FIG. 2 b).

All dynamic, non-linear transmission elements (two-port Z, U and three-port D) are composed of dynamic, linear two-port and / or memoryless, non-linear two-port N and / or logic elements (e.g. adders, multipliers).

The free, variable parameters of the dynamic, linear two-port (linear filter parameters) and the memoryless, non-linear two-port (non-linear characteristics) are measured by measuring the resulting transmission behavior (converter with equalization network), with the help of a matching arrangement, which is temporary or permanent to the converter equalizer System is connected, determined and so the equalization system is automatically adapted to the respective converter.

The equalizer network will initially be further specified for the electrodynamic sound transmitter, which is operated in a bass reflex or compact box system. Starting from an electrical equivalent circuit diagram with concentrated elements, the non-linear integro differential equation (IDG) is set up, the equalizer transfer function is determined and implemented in a circuit arrangement. The non-linear equivalent circuit diagram (see FIG. 7 a) differs from the linear one in that current and deflection-dependent parameters or quantities occur.

The stiffness of the membrane suspension s _T (x) and the stiffness of the coupled air volume s _B (x) are summarized in a constant overall stiffness s _o and in a deflection-dependent overall stiffness s _G (x)

${\text{s}}_{\text{O}}{\text{+ s}}_{\text{G}}{\text{(x) = s}}_{\text{T}}{\text{(x) + s}}_{\text{B}}\text{(x). (1)}$

The dependence on the deflection is also taken into account in the acting electrodynamic transducer parameter Bl (x), in the voice coil inductance L (x), and in the electromagnetic driving force F _mag (i, x).

zusammengefaßt.The elements of the mechanical-acoustic vibration system that have constant parameters are in the impedance

summarized.

Using the Laplace operator, the inverse Laplace transformation and the folding operation, the following nonlinear equation (IDQ) can be set up in the time domain from the equivalent circuit diagram when fed with a constant current source

soll das Gesamtsystem linearisiert und die folgende lineare Gleichung (IDG) erfüllt werden:

${\text{Bl}}_{\text{o}}\text{·i(t) = L⁻¹{}\underline{\text{J}}\text{(s)}*x(t) . (4)}$

The multiplication or division in the time domain (point) must be distinguished from the convolution. By connecting a suitable equalizer with the transfer function

${\text{i}}_{\text{L}}\text{(t) = f [i (t)]}$

the entire system should be linearized and the following linear equation (IDG) should be fulfilled:

${\text{Bl}}_{\text{O}}\text{· I (t) = L⁻¹ {}\underline{\text{J}}\text{(s)} * x (t). (4)}$

mit $\text{x(t) = L⁻¹{X(s)} * i(t)}$

besitzen.The nonlinear equalizer network must do the following transfer function for this

${\text{i}}_{\text{L}}{\text{(t) = {i (t) + N}}_{\text{s}}{\text{(x) + i (t) ² · N}}_{\text{M}}{\text{(x)} · N}}_{\text{B}}\text{(x), (5)}$

With $\text{x (t) = L⁻¹ {X (s)} * i (t)}$

have.

nachgebildet werden.Since the overall system fulfills the linear equation (IDG) (4) after the equalization has been implemented upstream, the deflection-equivalent time signal x (t), which acts here as a control variable, can be implemented by a linear transmission element (low pass) with the following transfer function

be replicated.

For the frequency-independent, non-linear functions N _s (x), N _M (x) and N _B (x), the following relationships to the deflection-dependent transducer parameters can be specified:

Operating the electrodynamic converter system with a constant current source does, however, require more effort in the area of the power amplifier by inserting a voltage-current converter and requires additional measures to ensure a balanced sound pressure amplitude frequency response, but simplifies the non-linear equalization. The predistorted input signal is expediently converted into a current signal only at the power amplifier.

In the case of voltage supply to the converter, the effect of the voice coil resistance and the voice coil inductance leads to a more complicated nonlinear differential equation and a correspondingly more complex equalization system.

The following nonlinear equation (IDG) results from the equivalent circuit diagram for voltage supply:

soll das Gesamtsystem linearisiert und die folgende lineare Gleichung (IDG) erfüllt werden:

${\text{Bl}}_{\text{o}}{\text{·u = R}}_{\text{e}}\text{·L⁻¹{}\underline{\text{J}}{\text{(s)}*x + L}}_{\text{o}}\text{·L⁻¹{p·}\underline{\text{J}}{\text{(s)}*x + Bl}}_{\text{o}}\text{²·L⁻¹{s}*x (11)}$

By connecting a suitable equalizer with the transfer function

${\text{u}}_{\text{L}}\text{(t) = f [u (t)]}$

the entire system should be linearized and the following linear equation (IDG) should be fulfilled:

${\text{Bl}}_{\text{O}}{\text{· U = R}}_{\text{e}}\text{· L⁻¹ {}\underline{\text{J}}{\text{(s)} * x + L}}_{\text{O}}\text{· L⁻¹ {p ·}\underline{\text{J}}{\text{(s)} * x + <figure-callout id="2" label="Bl O" filenames="imgf0001.png,imgf0002.png" state="{{state}}">Bl </figure-callout>}}_{\text{O}}\text{² · L⁻¹ {s} * x (11)}$

mit

$\text{x(t) = L⁻¹{X(s)} * u(t)}$

und

besitzen.The nonlinear equalizer network must do the following transfer function for this

With

$\text{x (t) = L⁻¹ {X (s)} * u (t)}$

and

have.

aus dem unverzerrten Eingangssignal u(t) und der Strom i_L(t) unter Benutzung der linearen Übertragungsfunktion

bestimmt werden.Since the overall system fulfills the linear equation (IDG) (11) after the equalization, the deflection-equivalent time signal x (t) can be carried out using a linear system (low pass) with the following transfer function

from the undistorted input signal u (t) and the current i _L (t) using the linear transfer function

be determined.

${\text{N}}_{\text{L}}{\text{(x) = L(x) - L}}_{\text{o}}\text{. (20)}$

For the frequency-independent, non-linear functions N _s , N _M , N _D , N _L and N _B , the following relationships to the deflection-dependent transducer parameters can be specified

${\text{N}}_{\text{L}}{\text{(x) = L (x) - L}}_{\text{O}}\text{. (20)}$

The circuits of the equalizer for current and voltage supply can be derived directly from the non-linear transfer functions (5), (12). The point operations contained correspond to multiplications in the time domain. The convolution with a constant weight function corresponds to a linear system (filter) connected in the transmission path. The nonlinear functions are realized by memoryless, nonlinear two gates.

For the desired change or compensation of the deflection-dependent rigidity, the equalizer network contains a three-port D _S (FIG. 9), which consists of a more linear, dynamic network X (100), a memoryless, non-linear two-port N _S (101) and an adder (103) consists. The input E₂ (22) of the three-way monitor is connected to the input of the two-port X. The output of the two-port X, which carries a deflection-equivalent signal, is connected to the input of an adder via the memoryless, non-linear two-port N _S. The second input of the adder is connected to the input E₁ and the output of the adder and the output A of the Dreitor D _S are interconnected.

For the desired change or compensation of the deflection-dependent electrodynamic coupling factor, the equalizer network contains a three port D _B (FIG. 10), which consists of a more linear, dynamic network X, a memoryless, non-linear two port N _B (104) and a multiplier (105). The input E₂ of the Dreitor is connected in series via the linear two-port X and the memoryless, non-linear two-port N _B to the input of the multiplier. The second input of the multiplier is connected to the input E 1 and the output of the multiplier is connected to the output A of the Dreitor D _S.

For the desired change or compensation of the deflection-dependent damping, the equalizer network contains a three-port D _D (FIG. 11), which consists of a more linear, dynamic network X, a differentiator (108), a memoryless, non-linear two-port N _D (106) and an adder - And multiplier (103, 107). The input E₂ of the three-way monitor is connected via the two-port X to both the memoryless, non-linear two-port N _D and the input of a differentiator. The outputs of the differentiator and the memoryless, non-linear two-port N _D are linked together via a multiplier and connected to the input of an adder. The second input of the adder is connected to the input E 1 and output of the adder and the output A of the three-phase D _D.

To compensate for the electromagnetic drive, the equalizer network contains a three port D _M , which consists of a linear, dynamic network X, a memoryless, non-linear two port N _M (110), a square (108), a multiplier (109), and an adder (103) exists. The input E₂ of the three-way monitor is connected to sound transmitters that are fed via a constant current source (FIG. 13), both directly to the input of the squaring stage and via the two-port X to the input of the memory-free, non-linear two-port N _M. The outputs of the squarer and the two-port N _M are linked via a multiplier and fed to the input of an adder. The second input of the adder is connected to the input E 1 and the output of the adder is connected to the output A of the Dreitor D _M.

If the sound transmitter is operated via a voltage source (FIG. 12), the input signal of the squaring stage, which corresponds to the input current of the converter, is generated with the aid of a non-linear network (111) according to relationship (13).

For this purpose, the deflection-equivalent signal at the output of the two-port X is fed both to a linear two-port with the transfer function I (s) and to the non-linear, non-linear two-port N _S , N _B. The output of the linear two-port I and the output of the two-port N _S are combined in an adder and fed to one input of a multiplier. The other input of the multiplier is connected to the output of the non-linear two-port N _B. The output of the multiplier carries the input current equivalent signal.

To compensate for the deflection-dependent inductance of a voltage-fed sound transmitter, the equalizer network contains a three-port network D _L (FIG. 14), which consists of a more linear, dynamic network X, a non-linear network (111), a differentiator (112) and a non-linear two-port N _L (110 ) and a multiplier (109) and adder (103). The input E₂ of the three-way connector is connected via the linear two-port X to the non-linear two-port N _L. The output of the two-port N _L and the output of the current simulation (111) described above are connected to the inputs of the multiplier. The output signal is fed to one input of an adder via a differentiator. The second input of the adder is connected to the input E 1 and the output of the adder is connected to the output A of the Dreitor D _L.

In the case of simultaneous compensation of the electrodynamic drive and other converter parameters, the compensation three-way gates must be connected to one of their two inputs and the output in a chain such that, apart from the three-port D _L of inductance compensation, all other three-port sides are connected to the three-port D _B on the input side (FIG. 4 ). The output of the compensation third-party D _L must always be connected to the transducer inputs of the sound transmitter.

This circuitry arrangement of the compensation three-way gate results directly from the analytical structure of the transfer function (large curly brackets in 5 and 12 respectively) and corresponds to the mirror symmetry between Equalizer structure (signal flow diagram in Fig. 20 a) and the active structure (signal flow diagram 7 b) of the nonlinear physical mechanisms in the electrodynamic loudspeaker. Only in this order can the distortions caused by the deflection of the voice coil be fully compensated.

The deflection of the membrane changes not only the electrical and mechanical parameters of the transducer, but also the acoustic radiation conditions, i.e. the distance between the current membrane position and a fixed reception point in the main radiation direction (axis) depends on the deflection and leads to a different transit time of the signal in the acoustic system. In particular, high-frequency signal components with short wavelengths are impaired by the resulting phase or frequency modulation (known as the Doppler effect) and generate additional intermodulation distortions ([5] GL Beers and H.Belar, "Frequency-Modulation Distortion in Loudspeakers", J. Audio Eng. Soc ., Volume 29, pages 320-326, May 1981).

wobei die Impulsantwort

die Abstrahlung und Ausbreitung des akustischen Signales beschreibt und die veränderliche Laufzeit des Signales im akustischen System berücksichtigt.In order to also compensate for these distortions by predistortion of the electrical feed signal, this distortion mechanism is also modeled and the required transfer function of the equalization network is derived and the required circuit structure is determined. The sound pressure p (t) occurring at a reception point in the main emission direction results from folding the deflection x (t) of the membrane with the impulse response

$\text{p (t) = h (t, x (t)) * x (t) (21)}$

being the impulse response

describes the radiation and propagation of the acoustic signal and takes into account the variable duration of the signal in the acoustic system.

With the help of the Diracfunction δ (t), the constant acoustic impulse response h _o (t) can be separated from the variable transit time, which results from the quotient of deflection x (t) and speed of sound c.

beschrieben werden.In combination with the linear transfer function of the (equalized) electromechanical transducer X (s), the relationship between the electrical input signal u _L (t) and the resulting sound pressure can

to be discribed.

vorverzerrt, so lassen sich die Veränderungen der Laufzeit

${\text{p(t) = h}}_{\text{o}}{\text{(t) * L⁻¹{X(s)} * δ(t - T}}_{\text{o}}\text{- T₁) * u(t) (25)}$

und somit die Dopplerverzerrungen in der Hauptabstrahlrichtung kompensieren.The electrical input signal of the converter with the filter function

predistorted, so the runtime changes

${\text{p (t) = h}}_{\text{O}}{\text{(t) * L⁻¹ {X (s)} * δ (t - T}}_{\text{O}}\text{- T₁) * u (t) (25)}$

and thus compensate for the Doppler distortions in the main emission direction.

The transfer function of the equalizer (24) can be implemented in terms of circuitry with the aid of a transfer element with a variable, controllable transit time. A control-equivalent signal x (t) is required for control. This signal can be obtained from the electrical signal u _L (t) using a linear filter with the transfer function X (s). Considering this correction network as a three-port D _T , whose input E₁ (21) is fed with the signal u (t) and whose output A (25) to Converters leads, the control input E₂ (22) is connected to the output A. Thus, the compensation network for Doppler distortions is one of the retroactive, feedback circuit structures (see FIG. 2 b).

If other non-linear causes of distortion (e.g. force factor, damping, inductance) act in the electrodynamic sound transmitter, the corresponding compensation multipliers (see D _D (15), D _B (16), D _L (17) in Fig. 4) are after the compensation triad the Doppler distortions (D _T (14)). Only in this way can the control signal x (t) required for the compensation of all deflection-related distortions be obtained from the electrical signal with the aid of a linear filter, and these distortions can be completely suppressed. The resulting overall equalization network thus consists of a chain connection of two nonlinear, dynamic transmission links (see two gates Z1 and Z2 in FIG. 4), the distortions of the acoustic system and the second link compensating for the distortions of the electromechanical system. Here, too, complete symmetry properties are shown between the structure of the equalizer (FIG. 20 a) and the active structure of the converter (signal flow diagram FIG. 7 b).

24 shows a possibility of realizing the equalizer distorter D _T to compensate for the Doppler distortions.

The control input E2 (22) of this three port is connected to the input of the linear filter (100), which has the transfer function X (s) and at whose output a deflection-equivalent signal x (t) is produced.

The input E1 (21) is connected to the input of a delay element (138), at the output of which the input signal appears after 20 µs delay without further distortion. With the help of two adders (136, 134), a subtractor (135) and a multiplier (137), the instantaneous signal x (t) is interpolated between the instantaneous and the delayed signal.

By coupling special sound guides to the sound transmitter, the efficiency can be increased considerably and the distortion caused by deflection can be reduced. However, non-linear flow and compression processes in sound guidance can also cause strong non-linear distortions in the emitted sound. First of all, the physical background of these mechanisms is to be explained on the basis of a modeling of the sound transmitter with horn sound guidance, and then the equalizer transfer function and the corresponding circuit structure are to be derived.

_K und Nachgiebigkeit der Druckkammer

_D weisen eine Abhängigkeit von akustischen Zustandsgrößen auf. Bei einem sehr großem Schallfluß q_K ist die Strömung am Trichtereingang nicht mehr laminar. Durch die Ausbildung von Turbulenzen entstehen neben der viskosen Reibung weitere Verluste, die zum Anstieg des summarischen Reibungsparameters (Strömungswiderstand) führen.At the funnel entrance, the sound flow passes through a cross-sectional jump, so that a pressure chamber is created between the vibrating membrane and the funnel entrance. The parameters of the acoustic elements friction in the funnel entrance

_K and compliance of the pressure chamber

_D are dependent on acoustic state variables. With a very large sound flow q _K , the flow at the funnel entrance is no longer laminar. The formation of turbulence creates, in addition to viscous friction, further losses which lead to an increase in the overall friction parameter (flow resistance).

Werden alle akustischen und mechanischen Elemente auf die elektrische Seite transformiert so läßt sich eine äquivalente elektrische Ersatzschaltung (Fig. 8) angeben. Die linearen Elemente des mechano-akustischen Systems werden in der komplexen Impedanz

zusammengefaßt.The second non-linear mechanism is caused by the (adiabatic) compression of the air in the pressure chamber. The resilience of the enclosed air volume V decreases with increasing pressure p _D in the chamber and can be described by the following relationship

If all acoustic and mechanical elements are transformed to the electrical side, an equivalent electrical equivalent circuit (FIG. 8) can be specified. The linear elements of the mechano-acoustic system are in the complex impedance

summarized.

und die äquivalenten nichtlinearen Größen der akustische Druckkammernachgiebigkeit

und der akustischen Dämpfung

die in einen konstanten Anteil N_o, R_o und einen abhängigen Teil N(i_D) und R(u_K) aufgespalten sind.The equivalent electrical quantity of the acoustic horn input impedance also appears

and the equivalent non-linear magnitudes of acoustic pressure chamber compliance

and acoustic damping

which are split into a constant part N _o , R _o and a dependent part N (i _D ) and R (u _K ).

$\text{= L⁻¹{}\underline{\text{W}}\text{₁(s)·}\underline{\text{Z}}\text{(s) + W(s)·(}\underline{\text{Z}}{\text{(s).N}}_{\text{o}}{\text{+ 1/s)}*u}}_{\text{K}}\text{ (31)}$

unter Benutzung der Faltungsoperation (*), der inversen Laplacetransformation (L⁻¹{ }), des Laplaceoperators (s) und folgender Summenimpedanzen

$\underline{\text{F}}{\text{(s) = N}}_{\text{o}}\text{·}\underline{\text{W}}\text{(s) +}\underline{\text{W}}\text{₁(s), (33)}$

und

The following nonlinear equation (IDG) in the time domain can be derived from the equivalent circuit diagram

${\text{u}}_{\text{L}}\text{- L⁻¹ {}\underline{\text{W}}{\text{(s)} * (N (i}}_{\text{D}}{\text{) · [U}}_{\text{K}}\text{* L⁻¹ {}\underline{\text{Z}}{\text{(s)}] + N (i}}_{\text{D}}{\text{) U}}_{\text{K}}{\text{· R (u}}_{\text{K}}\text{)) - L⁻¹ {}\underline{\text{F}}{\text{(s)} * [u}}_{\text{K}}{\text{· R (u}}_{\text{K}}\text{)]}$

$\text{= L⁻¹ {}\underline{\text{W}}\text{₁ (s)}\underline{\text{Z}}\text{(s) + W (s) · (}\underline{\text{Z}}{\text{(s) .N}}_{\text{O}}{\text{+ 1 / s)} * u}}_{\text{K}}\text{(31)}$

using the convolution operation (*), the inverse Laplace transform (L⁻¹ {}), the Laplace operator (s) and the following sum impedances

$\underline{\text{F}}{\text{(s) = N}}_{\text{O}}\text{·}\underline{\text{W}}\text{(s) +}\underline{\text{W}}\text{₁ (s), (33)}$

and

soll das Gesamtsystem linearisiert und die folgende lineare Gleichung (IDG) erfüllt werden:

$\text{u(t) = L⁻¹{}\underline{\text{W}}\text{₁(s)·}\underline{\text{Z}}\text{(s) +}\underline{\text{W}}\text{(s)·[}\underline{\text{Z}}{\text{(s)·N}}_{\text{o}}{\text{+ 1/s]} * u}}_{\text{K}}\text{ (36)}$

By connecting a suitable equalizer with the transfer function

${\text{u}}_{\text{L}}\text{(t) = f [u (t)] (35)}$

the entire system should be linearized and the following linear equation (IDG) should be fulfilled:

$\text{u (t) = L⁻¹ {}\underline{\text{W}}\text{₁ (s)}\underline{\text{Z}}\text{(s) +}\underline{\text{W}}\text{(s) · [}\underline{\text{Z}}{\text{(s) · N}}_{\text{O}}{\text{+ 1 / s]} * u}}_{\text{K}}\text{(36)}$

mit

${\text{i}}_{\text{D}}{\text{(t) = [u}}_{\text{K}}\text{(t) * L⁻¹{}\underline{\text{Z}}{\text{(s)}] + N}}_{\text{R}}{\text{(u}}_{\text{K}}\text{(t))}}$

und

${\text{u}}_{\text{K}}\text{(t) = u(t) * L⁻¹{}\underline{\text{Y}}\text{(s)}].}$

The nonlinear equalizer network must have the following transfer function for this:

${\text{u}}_{\text{L}}\text{(t) = u (t) + L⁻¹ {}\underline{\text{W}}{\text{(s)} * N}}_{\text{A}}{\text{(i}}_{\text{D (t)}}\text{) + L⁻¹ {}\underline{\text{F}}{\text{(s)} * N}}_{\text{R}}{\text{(u}}_{\text{K (t)}}\text{) (37)}$

With

${\text{i}}_{\text{D}}{\text{(t) = [u}}_{\text{K}}\text{(t) * L⁻¹ {}\underline{\text{Z}}{\text{(s)}] + N}}_{\text{R}}{\text{(u}}_{\text{K}}\text{(t))}}$

and

${\text{u}}_{\text{K}}\text{(t) = u (t) * L⁻¹ {}\underline{\text{Y}}\text{(s)}].}$

nachgebildet werden.Since the overall system fulfills the linear equation (IDG) after the equalization, the control signal u _K (t) can be carried out by a linear system with the following transfer function

be replicated.

${\text{N}}_{\text{R}}{\text{(u}}_{\text{K}}{\text{) = u}}_{\text{K}}{\text{·R(u}}_{\text{K}}\text{) (40)}$

zu den Wandlerparametern angeben.The following relationships can be used for the frequency-independent nonlinear functions

${\text{N}}_{\text{A}}{\text{(i}}_{\text{D}}{\text{) = N (i}}_{\text{D}}{\text{) · I}}_{\text{D}}\text{, (39)}$

${\text{N}}_{\text{R}}{\text{(u}}_{\text{K}}{\text{) = u}}_{\text{K}}{\text{· R (u}}_{\text{K}}\text{) (40)}$

specify the converter parameters.

The non-linear transfer function of the equalizer can be converted directly into a circuit. The convolution operations are carried out by linear filters with the transfer functions Y (s), F (s), Z (s), W (s) and the non-linear functions N _A and N _R are implemented by memoryless, non-linear transfer systems. The signals are linked in accordance with the algebraic structure of the equalizer function (32) with adders and multipliers.

This results in the following structure for the three-port D _A (FIG. 15), which effects a desired change or compensation of the adiabatic compression in the coupled sound guide of a sound transmitter: The input E 2 of the three-port D _A is via a transmission element (115) connected to the input of a memoryless, non-linear transmission element N _A (114). The output of the two-port N _A is connected via the linear transfer two-port W (113) to the first input of an adder (103) and the second input of the adder is connected to the input E 1 of the three-way monitor. The output of the adder being connected together to the output A of the D Dreitors _A.

For the Dreitor D _R (Fig. 16), which causes a desired change or compensation of the fast-dependent flow losses in the coupled sound guide of a sound transmitter, the following circuit structure results: The input E₂ of the Dreitor D _R is via a linear, dynamic transmission element Y (118) connected to the input of a memoryless, non-linear transmission element N _R (119). The output of the two-port N _R is connected via the linear transmission element F (120) to the first input of an adder (103) and the second input of the adder is connected to the input E 1 of the three-way monitor. The output of the adder is connected to the output A of the three-phase D _R.

$\underline{\text{Z}}{\text{(s) < R}}_{\text{o}}\text{, (42)}$

$\text{Realteil {}\underline{\text{Z}}{\text{}}_{\text{H}}\text{(s) } < Imaginärteil {}\underline{\text{Z}}{\text{}}_{\text{H}}\text{(s) }, (43)}$

kann das lineare Netzwerk

$\underline{\text{W}}\text{(s) ≈ s (44)}$

als einfacher Differenzierer und die linearen Netzwerke

$\underline{\text{F}}\text{(s) ≈}\underline{\text{W}}\text{₁(s) ≈ Realteil(}\underline{\text{W}}\text{₁(s)) = R₁ (45)}$

können als einfache, frequenzunabhängige Verstärker ausgeführt werden.The circuit can compromise the accuracy of the compensation be greatly simplified in certain frequency areas. Using relationships

$\underline{\text{Z}}\text{(s) <}\underline{\text{W}}\text{₁ (s) <}\underline{\text{W}}\text{₂ (s), (41)}$

$\underline{\text{Z}}{\text{(s) <R}}_{\text{O}}\text{, (42)}$

$\text{Real part {}\underline{\text{Z}}{}_{\text{H}}\text{(s)} <imaginary part {}\underline{\text{Z}}{}_{\text{H}}\text{(s)}, (43)}$

can the linear network

$\underline{\text{W}}\text{(s) ≈ s (44)}$

as a simple differentiator and the linear networks

$\underline{\text{F}}\text{(s) ≈}\underline{\text{W}}\text{₁ (s) ≈ real part (}\underline{\text{W}}\text{₁ (s)) = R₁ (45)}$

can be designed as simple, frequency-independent amplifiers.

The electrodynamic sound receiver (microphone) also generates non-linear signal distortions when there is high sound pressure in the lower frequency range. The physical background is first explained using a model of the electrodynamic sensor with concentrated electrical and mechanical elements, and then the equalizer network is derived.

All effective acoustic elements of the sensor are described by equivalent mechanical elements. With the help of a membrane with the area S _M , a sound pressure signal p _m (t) is converted into a force signal F (t) which drives the mechanical vibration system.

The stiffness of the membrane suspension s _T (x) and the stiffness of the coupled air volume s _B (x) are summarized in a constant overall stiffness s _o and in a deflection-dependent overall stiffness s _G (x).

${\text{s}}_{\text{O}}{\text{+ s}}_{\text{G}}{\text{(X) = s}}_{\text{T}}{\text{(x) + s}}_{\text{B}}\text{(x) (48)}$

The dependence on the deflection is also taken into account in the acting electrodynamic transducer parameter Bl (x) and the acoustic-mechanical total damping is split into a constant part z _o and a deflection-dependent part z (x).

zusammengefaßt.All elements of the mechanical-acoustic vibration system that have constant parameters are in the mechanical impedance

summarized.

The amplifier connected to the sensor should have a sufficiently high internal resistance so that the resistance and inductance of the voice coil can be neglected.

Using the Laplace operator s, the inverse Laplace transform and the convolution operation, the nonlinear equation (IDG) can be set up in the time domain

$\text{F (t) = v (t) * L⁻¹ {}\underline{\text{e.g.}}{\text{(s)} + v (t) * z (x (t)) + x (t) * s}}_{\text{G}}\text{(x (t)) (50)}$

The force F is the input variable of the transducer and the voice coil deflection x acts as a parameter-changing state variable. The voltage at the converter terminals results from

${\text{u}}_{\text{L}}\text{(t) = v (t) Bl (x (t)) (51)}$

soll das Gesamtsystem linearisiert und die folgende lineare Gleichung (IDG) erfüllt werden

By connecting a suitable equalizer with the transfer function

${\text{u (t) = f [u}}_{\text{L}}\text{(t)] (52)}$

the entire system is to be linearized and the following linear equation (IDG) is to be fulfilled

mit den Abkürzungen

und

besitzen. Aus den abhängigen Parametern des Sensors ergeben sich die frequenzunabhängigen, nichtlinearen Funktionen

wobei die Hilfsfunktion N_U(x) der Beziehung

genügt.The nonlinear equalizer network must do the following transfer function in the time domain

with the abbreviations

and

have. The frequency-independent, non-linear functions result from the dependent parameters of the sensor

where the auxiliary function N _U (x) of the relationship

enough.

The non-linear transfer function of the equalizer can be converted directly into a circuit. This circuit is a chain connection of two non-linear, dynamic two-port Z₂ and Z₃. The two-port Z₂, which immediately follows the sound receiver, contains the three-port D _BE for compensation of the electrodynamic coupling factor. The second two-port connected to the output of the three-way D _BE contains the three-way to compensate for the deflection-dependent damping and the rigidity.

The three port D _BE (FIG. 19) compensates for the coupling parameter which is variable in terms of deflection. The input E₂ of the Dreitor is connected in series via an integrating element (129), a serially coupled memoryless, non-linear transmission element N _BE (130) to the one input of a multiplier (131). The input E 1 is connected to the second multiplier input and the output of the multiplier is connected to the output A of the rotator D _BE .

The three-port D _SE (FIG. 17) effects a desired change or compensation of the stiffness of the diaphragm suspension which is variable in terms of deflection. The input E₂ of the Dreitor D _SE is connected via an integrating element (123), a memoryless, non-linear transmission element N _SE (122) and a linear two-port Q (121) to the one input of an adder (103). The second input of the adder is connected to the input E 1 and the output of the adder is connected to the output A of the Dreitor D _SE .

The Dreitor D _DE (Fig. 18) effects a desired change or compensation of the stiffness of the diaphragm suspension which is variable in terms of deflection. The input E₂ of the Dreitor D _DE is connected both directly to the one input of a multiplier (107) and via the chain connection of an integrating element (126) and a memory-free, non-linear transmission element N _DE (128) to the second input of the multiplier. The output of the multiplier is connected via a linear two-port Q (121) to the input of an adder, the second input of the adder is connected to the input E 1 and the output of the adder is connected to the output A of the three-phase D _DE .

In the electrostatic sensor (condenser microphone), the non-linear signal distortion is caused by the action of one constant parallel capacitance C _p , through the deflection-dependent electrical attraction between the membrane and counterelectrode and through the deflection-dependent compliance of the air cushion or the membrane.

These non-linearities can also be compensated for by an equalizer network according to the basic structure described. The membrane with the area S _M converts the sound pressure signal p _m (t) into a force signal F (t), which acts on the overall compliance in the frequency range of interest.

zusammengefaßt werden.With regard to the equalizer network, the stiffness of the membrane s _T (x), the coupled air cushion s _B (x) and the effect of the electrical force of attraction should be in a constant overall stiffness s _o and in a deflection-dependent overall stiffness s _G (x)

${\text{s}}_{\text{O}}{\text{+ s}}_{\text{G}}{\text{(x) = s}}_{\text{T}}{\text{(x) + S}}_{\text{B}}{\text{(x) + s}}_{\text{A}}{\text{(x, U}}_{\text{O}}\text{). (59)}$

be summarized.

A polarization voltage U _{o is} built up between the membrane and the counter electrode of the electrostatic sensor and the input resistance of the coupled amplifier is so high that no charges can flow off at the signal frequencies of interest. In addition to the capacitance C _o between the membrane and counterelectrode, which is controlled by the deflection of the membrane, a second constant parallel capacitance C _p acts.

This results in the relationship between deflection x and signal output voltage

soll das Gesamtsystem linearisiert und die folgende lineare Übertragungsfunktion

erfüllt werden. Das nichtlineare Entzerrernetzwerk muß hierfür die folgende Übertragungsfunktion im Zeitbereich besitzen.

mit

Das Entzerrernetzwerk ist frequenzunabhängig und entspricht einem einfachen gedächtnislosen, nichtlinearen Zweitor.By connecting a suitable equalizer with the transfer function

${\text{u (t) = f [u}}_{\text{L}}\text{(t)] (61)}$

the entire system should be linearized and the following linear Transfer function

be fulfilled. For this, the nonlinear equalizer network must have the following transfer function in the time domain.

With

The equalizer network is frequency-independent and corresponds to a simple, memory-free, non-linear two-port.

Now that the circuit structure of the non-linear equalizer networks has been developed for various electroacoustic transducers, the problem of adapting these equalizer networks to the transducer is now to be solved. The nonlinear distortions in the overall system can only be reduced below 1% if the characteristic curves in the memoryless, nonlinear two-ports are brought to the optimum values at least in the same order of magnitude.

According to the invention, the equalizer network has changeable properties, ie the parameters of the equalizer network, in particular the non-linear, memoryless two-ports, can be changed via at least one control input. On the control lines of the parameter control there are aids for storing the set control value (holding circuits) in order to retain the determined parameter setting even after the adjustment process has ended. A further circuit-technical aid is activated to adapt the network. It consists of a generation part for generating an excitation signal and an analysis part for recording and evaluating a measurement signal and for generating control signals for setting the equalizer parameters.

The adapter arrangement can be designed as a control circuit or as a control circuit.

A separate adaptation is possible in the control circuit, in which the converter is initially connected to the measuring arrangement to form a measuring chain without an equalizer network, and the nonlinear converter parameters are determined and stored in the holding circuits. After measuring the converter parameters, the equalizer network is coupled to the converter again and the outputs of the holding circuits are connected to the control inputs of the equalizer network.

A simultaneous adaptation appears to be more advantageous, in which the generation part is connected to the transducer-equalizer system and the analysis part to form an electrode.

The output of the analysis section is connected to the control input of the equalization network, so that the control signals generated in the analysis section change the parameters of the equalization network and adapt the system to the converter. A main control system takes over the control and control of the subsystems during the adjustment process.

When adapting equalizer networks to sound transmitters, the generation part is connected to the input terminals of the converter via the equalizer network. The measurement signal can be derived via an impedance measurement or via an acoustic measurement. The acoustic measurement requires an additional sound receiver, but reduces the technical effort in the subsequent analysis section.

For practical implementation, it is desirable to only change the parameters of non-linear, memoryless two-ports in the equalizer network and to largely avoid changing the linear, frequency-dependent two-port parameters. In the case of the electrodynamic sound transmitter, the overall arrangement can be adapted to the transmission behavior of the two-port X by means of the three-port damping and stiffness compensation. As a result, the adaptation effort can be reduced and, at the same time, a desired linear overall transmission behavior can be realized.

In the analysis part, the individual distortion components are separated from the recorded measurement signal (microphone signal) with a spectral or correlation analysis and the control signals are derived.

In the correlation analysis, it is first necessary to transfer the excitation signal from the generation part to the analysis part and to form reference signals from the excitation signal. For this purpose, the excitation signal is conducted via non-linear, dynamic two-ports, which synthetically simulate the non-linear causes of distortion of the converter and separate individual distortion components. The frequency and phase position of the reference signals, but not their amplitude, is important for the correlation analysis. The measurement signal and a reference signal are fed to the two inputs of the correlator. The correlator consists of a multiplier and a downstream low-pass filter. The correlation signal is used directly to control the equalizer network.

The adaptation process is carried out with various signal modulations in order to achieve the best possible match and ultimately compensation in the small and large signal range. In the case of a step-by-step excitation signal, the optimal equalizer parameters intended for lower modulation can be adopted and only the curve sections relevant for the extended modulation range can be changed.

In the event that the converter equalizer system has reached its modulation limits and, for example, the deflection of the voice coil or the power supplied and converted into heat can destroy the converter, it is advisable to arrange a non-linear, dynamic two-port Z _SS in the equalizer network. The two-port Z _SS has the same structure as the other non-linear equalizer blocks. It contains non-linear, dynamic three-port D _SS for modulation limitation and for power limitation.

Between the input E₁ and the output A of the three-gate a controllable, non-linear network H switched, which has, for example, a high-pass characteristic. The input E₂ is connected via a linear network O, via a memoryless, non-linear two-port N _O and via a further linear two-port B to the control input of the two-port H.

To implement the deflection protection, the linear two-port O has the transfer function X (s) and generates a deflection-equivalent signal. The non-linear two-port N _O is a rectifier and the downstream two-port has a low-pass characteristic.

To limit the power loss in the converter, the linear two-port O has a transfer function derived from the electrical input impedance. The non-linear two-port N _O contains a squarer and the subsequent linear two-port B is an integrator, the integration time of which corresponds to the heating-up time (determined by thermal capacity and thermal conductivity) of the converter.

A change in the linear transmission properties of the two-port H (e.g. lowering of the bass signals through a high-pass filter) prevents the converter from being destroyed or the generation of non-linear distortions when the modulation limit (max. Deflection, max. Power loss) is reached.

• Fig. 1: das Prinzipschaltbild der erfindungsgemäßen Lösung des Entzerrernetzwerk für den Schallsender (a) und den Schallempfänger (b),
• Fig. 2 a rückwirkungsfreie Zusammenschaltung einzelner nichtlinearer, dynamischer Dreitore D zu einem Zweitor Z, Fig. 2 b: rückwirkende Zusammenschaltung einzelner nichtlinearer, dynamischer Dreitore D zu einem Zweitor Z,
• Fig. 3: Innenaufbau eines nichtlinearen, dynamischen Dreitors D,
• Fig. 4: Struktur des Entzerrernetzwerkes für einen elektrodynamischen Schallsender,
• Fig. 5: Struktur des Entzerrernetzwerkes für ein elektrodynamisches Mikrofon,
• Fig. 6: Struktur des Entzerrernetzwerkes für ein Kondensatormikrofon,
• Fig. 7 a: elektromechanisches Ersatzschaltbild für einen elektrodynamischen Schallsender,
• Fig. 7 b: Beschreibung des Übertragungsverhaltens eines elektrodynamischen Schallsender mit einem Signalflußplan,
• Fig. 8: Ersatzschaltbild des elektroakustischen Wandlers mit Hornschallführung (Druckkammerlautsprecher),
• Fig. 9: Dreitor D_S zur Kompensation der auslenkungsabhängigen Steifigkeit bei einem Schallsender,
• Fig. 10: Dreitor D_B zur Kompensation der auslenkungsabhängigen, elektrodynamischen Antriebes bei einem Schallsender,
• Fig. 11: Dreitor D_D zur Kompensation der auslenkungsabhängigen Dämpfung bei einem Schallsender,
• Fig. 12: Dreitor D_MU zur Kompensation des elektromagnetischen Antriebes bei einem Schallsender mit Konstantspannungsspeisung,
• Fig. 13: Dreitor D_MI zur Kompensation des elektromagnetischen Antriebes bei einem Schallsender mit Konstantstromspeisung,
• Fig. 14: Dreitor D_L zur Kompensation der auslenkungsabhängigen Induktivität bei einem Schallsender,
• Fig. 15: Dreitor D_A zur Kompensation der adiabatischen Kompression in der angekoppelten Schallführung eines Schallsenders,
• Fig. 16: Dreitor D_R zur Kompensation der turbulenten Strömung in der angekoppelten Schallführung eines Schallsenders,
• Fig. 17: Dreitor D_SE zur Kompensation der auslenkungsabhängigen Steifigkeit eines elektrodynamischen Schallempfängers, Fig. 18: Dreitor D_DE zur Kompensation der auslenkungsabhängigen Dämpfung eines elektrodynamischen Schallempfängers,
• Fig. 19: Dreitor D_BE zur Kompensation des auslenkungsabhängigen, elektrodynamischen Antriebes bei einem Schallempfänger,
• Fig. 20 a: Grobstruktur (Signalflußplan) eines Entzerrerungssystems für den elektrodynamischen Lautsprecher,
• Fig. 20 b: Ausführungsbeispiel für ein Entzerrernetzwerk für einen elektrodynamischen Lautsprecher zur Kompensation der auslenkungsabhängigen Steifigkeit, Dämpfung und des Kopplungsfaktors,
• Fig. 21: Ausführungsbeispiel für ein steuerbares, gedächtnisloses, nichtlineares Zweitor,
• Fig. 22: Prinzipschaltbild der Anordnung zur selbständigen, automatischen Anpassung des Entzerrernetzwerkes an den Wandler,
• Fig. 23: Ausführungsbeispiel für die automatische Anpaßanordnung.
• Fig. 24: Dreitor D_T zur Kompensation der auslenkungsabhängigen Laufzeit (Dopplereffekt) bei einem Schallsender,

In den Zeichnungen verkörpern die Ziffern folgende Elemente: Entzerrernetzwerk (1), Schallsender (2), Schallempfänger (3), lineare und nichtlineare Übertragungssysteme (4, 5, 6, 8, 9, 10), Verstärker (7), Eingang des Zweitores Z (11), Ausgang des Zweitores Z (12), nichtlineare, dynamische Übertragungsdreitore D (14, 15, 16, 17), Eingänge des ersten Dreitores (18, 19), Ausgang des letzten Dreitores (20), Eingang E₁ des Dreitores D (21), Eingang E₂ des Dreitores D (22), nichtlineares Übertragungssystem U (23), Verknüpfungselement (24), Ausgang A des Dreitors D (25), gedächtnisloses, nichtlineares Zweitor N_K (26), Entzerrernetzwerk (27), Multiplizierer (28, 33), Addierer (29, 30), Eingang des Entzerrers (31), Ausgang des Entzerrers (32), lineares Netzwerk mit der Übertragungsfunktion X(s) (34), gedächtnisloses, nichtlineares Zweitor (35, 37, 38), Differenzierer (36), Steuereingänge zur Parameterveränderung (39, 40, 41), Steuereingang zur Arbeitspunktumschaltung (42), Relais (43), Umschalter (44, 45, 46), Eingang des veränderbaren, gedächtnislosen, nichtlinearen Zweitores N (47), Halteschaltungen (48, 49, 50, 51, 52), Addierer (53, 54, 55, 56), Multiplizierer (57, 58, 59), spannungsgesteuerte Verstärker (60, 61, 62, 63), Ausgang des nichtlinearen Zweitores N (64), Tongeneratoren (65, 66), Addierer (67), lineares Netzwerk mit der Eingangsspannung-Auslenkung-Übertragungsfunktion des Wandlers (68, 69), Multiplizierer (70, 71, 72), lineare Netzwerke mit der Übertragungsfunktion des Wandlers (73, 74), Generierungsteil (75), Analyseteil (76), Multiplizierer (77, 78, 79, 80), Tiefpässe (81, 82, 83, 84), Differenzierer (85, 86), Umschalter (87), Relais (88), Hauptsteuersystem (89), spannungsgesteuerter Verstärker VCA (91), Audioeingang (93), Multiplizierer (95), Dreitor D_MI zur Kompensation des elektromagn. Antriebes bei Konstantspannungsspeisung (96), Dreitor D_MU zur Kompensation des elektromagn. Antriebes bei Stromspeisung (97), Dreitor D_L zur Induktivitätskompensation (98), Dreitor D_S zur Steifigkeitskompensation (99), lineares Netzwerk X zur Nachbildung der Auslenkung (100), gedächtnisloses, nichtlineares Zweitor N_S (101), Dreitor D_B zur elektrodyn. Antriebskompensation (102), Addierer (103), gedächtnisloses, nichtlineares Zweitor N_B (104), Multiplizierer (105), gedächtnisloses, nichtlineares Zweitor N_D (106), Multiplizierer (107), Differenzierer (108), Dreitor D_D zur Dämpfungskompensation (109), gedächtnisloses, nichtlineares Zweitor N_M (110), dynamisches Zweitor zur Nachbildung des Wandlereingangsstromes (111), Differenzierer (112), lineares Netzwerk W (113), gedächtnisloses, nichtlineares Netzwerk N_A (114), dynamisches Zweitor (115), Dreitor D_A zur Kompensation der adiabatischen Kompression (116), Dreitor D_R zur Kompensation der turbulenten Strömung (117), lineares Netzwerk Y (118), gedächtnisloses, nichtlineares Zweitor N_R (119), lineares Netzwerk F (120), lineares Netzwerk Q (121), gedächtnisloses, nichtlineares Zweitor N_SE (122), Integrator 1/s (123), Dreitor D_SE zur Steifigkeitskompensation (124), Dreitor D_DE zur Dämpfungskompensation (125), Integrator 1/s (126), gedächtnisloses, nichtlineares Zweitor N_DE (128), Integrierer (129), gedächtnisloses, nichtlineares Zweitor N_BE (130), Multiplizierer (131), Dreitor D_BE zur Kompensation des elektrodyn. Antriebes (132), Dreitor D_T zur Kompensation der auslenkungsabhängigen Laufzeit im akustischen System, Addierer (134), Subtrahierer (135), Addierer (136), Multiplizierer (137), Verzögerungsglied mit konstanter Verzögerungszeit (138), Addierer (139), Multiplizierer (140), Addierer (142 - 143), lineares Übertragungssystem X(s) (144), Übertragungsglied mit veränderlicher, steuerbarer Laufzeit (145), lineares Übertragungssystem (146), nichtlineares Übertragungssysteme (147 - 152), lineares Übertragungssystem (153), Signaleingang (154), Verzögerungsglied mit entgegengesetzter Steuercharakteristik (155), Subtrahierglieder (156 - 158, 160), Dividierglied (159), lineares Übertragungssystem (161), nichtlineare Übertragungsglieder (162 - 166), lineares Übertragungssystem (167), Quadrierer (168), Multiplizierer (169).Show in the drawings

• 1: the basic circuit diagram of the solution according to the invention of the equalizer network for the sound transmitter (a) and the sound receiver (b),
• 2a a non-reactive interconnection of individual non-linear, dynamic three-port doors D to form a two-port Z, FIG. 2 b: retroactive interconnection of individual non-linear, dynamic three-port doors D to form a two-port Z,
• 3: internal structure of a non-linear, dynamic Dreitor D,
• 4: Structure of the equalizer network for an electrodynamic sound transmitter,
• 5: structure of the equalizer network for an electrodynamic microphone,
• 6: structure of the equalizer network for a condenser microphone,
• 7 a: electromechanical equivalent circuit diagram for an electrodynamic sound transmitter,
• 7 b: Description of the transmission behavior of an electrodynamic sound transmitter with a signal flow plan,
• 8: equivalent circuit diagram of the electroacoustic transducer with horn sound guide (pressure chamber loudspeaker),
• 9: Dreitor D _S for compensation of the deflection-dependent stiffness in a sound transmitter,
• 10: Dreitor D _B for compensation of the deflection-dependent, electrodynamic drive in a sound transmitter,
• 11: Dreitor D _D for compensation of the deflection-dependent damping in a sound transmitter,
• 12: Dreitor D _MU for compensation of the electromagnetic drive in a sound transmitter with constant voltage supply,
• 13: Dreitor D _MI for compensation of the electromagnetic drive in a sound transmitter with constant current supply,
• 14: Dreitor D _L for compensation of the deflection-dependent inductance in a sound transmitter,
• 15: three-port D _A to compensate for the adiabatic compression in the coupled sound guide of a sound transmitter,
• 16: three-port D _R for compensation of the turbulent flow in the coupled sound guide of a sound transmitter,
• 17: Dreitor D _SE for compensation of the deflection-dependent stiffness of an electrodynamic sound receiver, Fig. 18: Dreitor D _DE for compensation of the deflection-dependent damping of an electrodynamic sound receiver,
• 19: Dreitor D _BE for compensation of the deflection-dependent, electrodynamic drive in a sound receiver,
• 20 a: rough structure (signal flow diagram) of an equalization system for the electrodynamic loudspeaker,
• 20 b: exemplary embodiment of an equalizer network for an electrodynamic loudspeaker to compensate for the deflection-dependent stiffness, damping and the coupling factor,
• 21: exemplary embodiment of a controllable, memoryless, non-linear two-port,
• 22: basic circuit diagram of the arrangement for independent, automatic adaptation of the equalizer network to the converter,
• Fig. 23: Exemplary embodiment for the automatic matching arrangement.
• 24: Dreitor D _T for compensating the deflection-dependent transit time (Doppler effect) in a sound transmitter,

In the drawings, the numbers represent the following elements: equalizer network (1), sound transmitter (2), sound receiver (3), linear and non-linear transmission systems (4, 5, 6, 8, 9, 10), amplifier (7), input of the two-port Z (11), output of the two-port Z (12), non-linear, dynamic transmission three-ports D (14, 15, 16, 17), inputs of the first three-port (18, 19), output of the last three-port (20), input E 1 of the three-port D (21), input E₂ of the three-port D (22), non-linear transmission system U (23), logic element (24), output A of the three-port D (25), memoryless, non-linear two-port N _K (26), equalizer network (27), Multiplier (28, 33), adder (29, 30), input of the equalizer (31), output of the equalizer (32), linear network with the transfer function X (s) (34), memoryless, non-linear two-port (35, 37, 38), differentiator (36), control inputs for changing parameters (39, 40, 41), control input for switching the operating point (42), rel ais (43), changeover switch (44, 45, 46), input of the changeable, memoryless, non-linear two-port N (47), holding circuits (48, 49, 50, 51, 52), adders (53, 54, 55, 56) , Multipliers (57, 58, 59), voltage-controlled amplifiers (60, 61, 62, 63), output of the non-linear two-port N (64), tone generators (65, 66), adders (67), linear network with the input voltage deflection transfer function of the converter (68, 69), multipliers (70, 71, 72), linear networks with the transfer function of the converter (73, 74), Generation section (75), analysis section (76), multiplier (77, 78, 79, 80), low pass filter (81, 82, 83, 84), differentiator (85, 86), changeover switch (87), relay (88), main control system (89), voltage-controlled amplifier VCA (91), audio input (93), multiplier (95), three-port D _MI to compensate for the electromagn. Drive with constant voltage supply (96), three-port D _MU to compensate the electromagn. Actuator with power supply (97), three-port D _L for inductance compensation (98), three-port D _S for stiffness compensation (99), linear network X for simulation of the deflection (100), memoryless, non-linear two-port N _S (101), three-port D _B for electrodyn. Drive compensation (102), adder (103), memoryless, non-linear two-port N _B (104), multiplier (105), memoryless, non-linear two-port N _D (106), multiplier (107), differentiator (108), three-port D _D for damping compensation (109), memoryless, non-linear two-port N _M (110), dynamic two-port for simulating the converter input current (111), differentiator (112), linear network W (113), memory-free, non-linear network N _A (114), dynamic two-port (115 ), Three-port D _A to compensate for adiabatic compression (116), three-port D _R to compensate for turbulent flow (117), linear network Y (118), memoryless, non-linear two-port N _R (119), linear network F (120), linear network Q (121), memoryless, non-linear two-port N _SE (122), integrator 1 / s (123), three-port D _SE for stiffness compensation (124), three-port D _DE for damping compensation (125), integrator 1 / s (126) , memoryless, non-linear two-port N _DE (128), integrator (129), memoryless, non-linear two-port N _BE (130), multiplier (131), three-port D _BE for compensation of the electrodyne. Drive (132), three-port D _T for compensation of the displacement-dependent travel time in the acoustic system, adder (134), Subtractors (135), adders (136), multipliers (137), delay elements with constant delay time (138), adders (139), multipliers (140), adders (142-143), linear transmission system X (s) (144), Transmission element with variable, controllable transit time (145), linear transmission system (146), non-linear transmission systems (147-152), linear transmission system (153), signal input (154), delay element with opposite control characteristic (155), subtracting elements (156-158, 160) ), Divider (159), linear transmission system (161), non-linear transmission elements (162-166), linear transmission system (167), squarer (168), multiplier (169).

The invention will be explained in the following using an exemplary embodiment and with reference to Figures 20, 21, 22 and 23. A simple example was chosen for reasons of clarity. The principle can be applied analogously to other and several parameters. An electrodynamic cone loudspeaker (2), mounted in a compact housing, is fed via a constant current source. With this loudspeaker, the electrodynamic drive proves to be the decisive cause of the distortion, so that only a nonlinear converter parameter has to be compensated for. The equalizer network used is shown in FIG. 20. It allows correction of the electrodynamic drive, the damping and the rigidity of the converter parameters. The network contains a linear low-pass filter (34) of second order X (s), a differentiator s (36), three memoryless, non-linear two-ports N _S (35), N _B (38), N _D (37) and three multipliers (33 , 28, 95) and two adding stages (29, 30). The input of the adder (30) and the input of the low pass X (34) are connected to the input (31) of the equalizer network. The output of the low-pass filter X (34), which carries a deflection-equivalent signal, is connected both to all inputs of the memoryless, non-linear two-ports (35, 37, 38) and the differentiating element (36) and to one input of the multiplier (95) . The second The input of the multiplier (95) is linked to the output of the non-linear two-port N _S (35). The output of the multiplier (95) is superimposed in the adder (30) with the undistorted signal. The output of the differentiating element (36) and the output of the non-linear two-port N _D (37) are connected to the inputs of the multiplier (33). The output of the multiplier is linked to the predistorted signal via the adder (29) and is fed to one input of the multiplier (28). The second input of the multiplier (28) is connected to the output of the memoryless two-port N _B (38). The output of the multiplier (28) is connected to the loudspeaker via an amplifier (7) with constant current supply.

The linear network is constructed as an active RC filter. The quality and the resonance frequency of the second order low-pass filter X (s) is determined in accordance with the desired linear transmission behavior. With the help of the three-port D _D and D _S contained in the equalizer circuit, the overall system can be corrected for the required linear properties for any loudspeaker with different resonance frequency and quality. The correspondence between the low-pass function X (s) and the linear transmission behavior of the overall arrangement is a necessary prerequisite for the functionality of the nonlinear equalizer.

Since in the present example the loudspeaker has no stiffness and damping non-linearities, only constant values are stored in the two gates N _S (35) and N _D (37). The non-linear characteristic of the memoryless two-port N _B (38) must, however, be adapted to the converter.

21 consists of a parallel connection of individual branches, each branch containing an exponentiation element (57, 58, 59) and a voltage-controlled amplifier (60, 61, 62, 63) which are connected via an adder element (53 , 54, 55, 56) before the exit (64) are summarized. In accordance with the Taylor series development, the order of the powers increases gradually from branch to branch and the gain change the VCA enables the approximation of any curve shape. A hold circuit (48, 49, 50, 51, 42) is connected to the control inputs of the amplifiers and stores the optimally set control voltage after the adaptation process. The control voltage of the linear (49, 60) and cubic branches (51, 58, 62) change the asymmetry of the characteristic. If the gain in the even-order potentiometers (61, 63) is increased, the symmetrical changes in the characteristic curve increase.

The control lines of the even and odd systems are each connected to a changeover switch (44, 45, 46) which are switched simultaneously by the main control unit (89) via the relay (43). The rotors of the changeover switches lead to the constant (39), symmetrical (41) and asymmetrical (40) correction inputs. In addition to the signal input and output, the changeable non-linear "two-port" also contains a control line (42) with which the changeover switch can be switched and various operating points can be selected in the characteristic curves. For very small input signals on the equalizer-converter system, the coefficients of the linear (49) and quadratic (50) elements are optimized in the lowest operating point. The order of the Taylor series approach or the number of parallel branches in the memoryless, non-linear two-port determines the number of additional operating points. They are appropriately distributed over the further modulation range of the converter.

The generating part (75) consists of two signal generators (65, 66) which generate a sinusoidal tone near the resonance frequency and a second higher-frequency tone. Both signals are added in an adder stage (67) and output to the equalizer network (1) via the switch (87) via a voltage-controlled amplifier (91). The main control unit (89) establishes this connection via the relay (88) during the adaptation process and switches back to the normal signal input (93) after adaptation. The equalizer network (1) is connected to the converter via a DC voltage-transmitting amplifier (7) (2) connected.

A microphone (3) is used to measure the sound pressure in the vicinity of the loudspeaker during the adjustment process and the electrical microphone signal is fed to the analysis part (76). The analysis part contains a correlator for each parameter to be adjusted, which was implemented with the aid of a multiplier (77, 78, 79, 80) and a downstream free pass (81, 82, 83, 84). The microphone signal is routed to one input of the correlator and a reference signal derived from the excitation signal to the other input. The amplitude of the reference signals is arbitrary and has no information value. However, the frequency and phase position of the reference signals correspond to the basic tones, harmonics or intermodulations in the microphone signal. The reference signal R (f₁) and R (f₂) at the multipliers (77, 78) is obtained by linear filtering (68, 89) with the transfer function X (s) of the linear two-port of the equalizer circuit from the excitation signal.

The reference signal R (f 1) is linked in the correlator (77, 81) with the microphone signal, then passed through a differentiator (85) to the control input (39) of the memory-free, non-linear two-port stiffness compensation. In the same way, the reference signal R (f₂) is fed to the correlator (78, 82) and its output is connected to the control input (39) of the damping compensation via a differentiating element (86). Both control signals change the constant portion of the memoryless, non-linear two gates N _S and N _D so that the linear transmission behavior (resonance frequency and quality) of the equalizer network converter system matches the transmission behavior X (s) and the output signal at the integrators ( 81) and (82) becomes maximum.

The reference signals R (f₁ + f₂) and R (2 · f₁ + f₂) are synthetically generated in an electronic replica of the nonlinear converter. This network is a circuit implementation of the modeling of the transmission behavior with the VOLTERRA series.

First, the signals f 1 and f 2 are passed through linear filters X (68, 89), multiplied together in (72) and filtered again with the linear transfer function of the converter (74). The reference signal R (f 1 + f 2) obtained in this way corresponds in phase and frequency to the intermodulations which are generated by asymmetries in the characteristic curve of the electrodynamic coupling factor ([6] Klippel, W.: Dynamic Measurement of Non-Linear Parameters of Electrodynamical Loudspeakers and their Interpretation 88. Conv. Of the Audio Eng. Soc., March 1990, preprint 2903). To form the reference signal R (2 · f₁ + f₂), the signal f1 is additionally squared before multiplication. The output signal of the multiplier (71) is also subjected to linear filtering (74) with the transfer function X.

The reference signal R (f₁ + f₂) is linked in the correlator (79, 83) with the microphone signal, then fed to the unbalanced control input (40) of the memory-free, non-linear two-port drive compensation N _B. In the same way, the reference signal R (2 · f₁ + f₂) is fed to the correlator (80, 84) and its output signal is connected to the symmetrical control input (41) of the memoryless, non-linear two-port N _{B of} the drive compensation. The characteristic curve is changed by both control signals so that the second and third order intermodulation products in the received measurement signal are reduced and the output signal of the integrators (83) and (84) runs towards zero. The sign of the correlation signal indicates over- or under-compensation by the equalizer network and leads to a decrease or increase in the voltage in the subsequent holding circuits (48, 49, 50, 51, 52) of the non-linearity without memory. After the individual assemblies of the adaptation system have been described, finally a functional representation of the overall system. When the adaptation process starts, the main control system (89) connects the equalizer input (31) to the generating part (75), switches on the lowest excitation voltage via the voltage-controlled amplifier (91) and starts the adaptation the constant of the two-port N _D , N _S and determines the optimal voltage value in the holding circuit (48). At the same time, the coefficients of the linear and quadratic branches are changed in the two-port N _B and optimal voltages in the holding circuits (49, 50) are determined. When the system has settled, the main control system (89) switches on the two higher coefficients of the Taylor development in N _B with the switches (44, 45), increases the excitation voltage and determines the optimum value for the holding circuits (51, 52). However, the constant parameters in the two-port N _S and N _D , ie the values in the holding circuits (48), are no longer changed. Once the operating points have been passed through, the main control system switches off the generating part (75) and connects the equalizer input (31) to the general signal input (93).

The advantages achieved with the invention consist in particular in realizing simple equalizer networks which largely take into account the converter-specific features and require a minimal number of components. The problem of adapting the equalizer network to the converter was solved with the aid of a further circuit arrangement. The adjustment system, which is activated at times, enables the optimum equalizer parameters to be determined and set independently. As a result, with the equalizer network coupled to the converter, both a desired change in the linear properties and a reduction in the non-linear distortions can be achieved over the entire modulation range of the converter.

Claims (11)

Circuit arrangement for correcting the linear and non-linear transmission behavior of electroacoustic transducers in the entire modulation range (small and large signal range), consisting of an electroacoustic transducer and an electrical equalizer network connected to the connection terminals,

characterized,

that the electrical equalizer network (1) consists of a chain connection (series connection) of two gates (transmission links Z₁, Z₂, ... Z _n ), with at least one two port (Z _i ) between its input and output port a non-linear, memory-free (frequency-independent, has static) or non-linear, dynamic transmission behavior and that the linear and non-linear transmission behavior of these two gates to the converter (2) with the aid of a matching arrangement that is temporarily or permanently connected to the converter (2, 3) and / or the equalizer network (1) , 3) can be automatically adjusted. Arrangement according to claim 1,

characterized,

that the non-linear two-port (Z) contains at least one three-port D _i , which consists of a non-linear, dynamic transmission element (23) (two-port U) and a memory-less logic element V (24) (e.g. adders, multipliers, etc.), that the two input signals of the logic element (24) are linked via an algebraic operation (z. B. multiplication or addition) to the output signal (25), wherein the one input (21) (E₁) of the Dreitor (D) directly with the one input of the linking element (24) (V) is connected and the other input (22) (E₂) of the three-port (D) via the two-port (23) (U) is connected to the second input of the linking element (24) (V) and the Output of the logic element (24) is connected to the output of the three-way gate (D) and that the two-port (23) (U) consists of dynamic, linear two-port and / or memoryless, non-linear two-port and / or link elements. Arrangement according to claim 2,

characterized by

that when using a three-port (D) in the two-port (Z) the input (21) (E₁) of the three-port (D) with the input (11) of the two-port (Z) and the output (25) (A) of the three-port (D ) is connected to the output (12) of the two-port (Z) and that the remaining input gate (22) (E₂) of the three-port (D) with the input port (11) of the two-port (Z) or with the output port (12) of the two-port (Z) is connected

or

that when using several three gates (D₁, ..., D _i ) in the two-port (Z) the entrance gate (21) (E₁) of the first entrance gate (D₁) with the entrance (11) of the two-port gate (Z), the exit gate (25 ) of the first three-port (D₁) is connected to the input (21) (E₁) of the subsequent second three-port (D₂) and that possible further three-ports (D₃, ..., D _i ) are connected to each other in the same way, so that all existing three gates (D₁, ..., D _i ) are arranged in a chain connection and that the output gate (25) (A) of the last three gate (D _i ) is connected to the output gate (12) of the two gates (Z) and that remaining entrance gates (22) (E₂) of all contained three gates are connected to the entrance gate (11) of the two-port gate (Z) or to the output gate (12) of the two-port gate (Z). Arrangement according to claim 2,

characterized,

that the input (22) (E₂) of the three-port (D) via a linear, dynamic transmission element (filter with low-pass characteristic) and via a non-linear, memoryless transmission element (two-port N) is serially connected to the one input of a logic element (V) and the second input of the logic element with the input (21) (E₁) of the Dreitor (D) and the output of the logic element (V) with the output (25) (A) of the Dreitor (D) are interconnected, the logic element in the case of compensation of the deflection-dependent force factor is a multiplier and in all other cases an adder. Arrangement according to claim 2,

characterized,

that the input (22) (E₂) of the Dreitor (D) is connected to a linear, dynamic transmission element (filter with low-pass characteristic), the output of this linear filter both via a linear, dynamic transmission element (108) (differentiating element) with one input a multiplier as well as a memoryless, non-linear transmission element (two-port N) is connected to the other input of the multiplier, the output of the multiplier to an input of an adder, the second input of the adder to the input (21) (E 1) of the three-port and the output of the adder are connected to the output (25) (A) of the three port (D). Arrangement according to claim 2,

characterized,

that the input (22) (E₂) of a three-way switch (D) is connected both to the input of a linear, dynamic transmission element (100) (filter with low-pass characteristic) and, in the case of power supply to the electro-dynamic sound transmitter, directly to the input of a square (168) is and in the case of voltage supply an additional dynamic, non-linear transmission element (111) between the input (22) (E₂) of the three-phase (D) and the input of the square (168) is connected, the output of the square (168) with the input of a Multiplier (109) and the output of the linear transmission element (100) via a downstream memoryless, non-linear transmission element (110) (N) is connected in series to the other input of the multiplier (169), the output of the multiplier (169) to the first input an adder (103), the second input of the adder (103) with the input (21) (E₁) of the Dreitor (D) and the output of the adder (103) are connected together with the output (25) (A) of the three-way switch (D). Arrangement according to claim 2,

characterized,

that the input (22) (E₂) of a Dreitor (D) both with the input of a linear, dynamic transmission element (filter with low-pass characteristic) and in the case of equalization of an electrodynamic microphone is directly connected to the input of a multiplier and in the case of equalization an electrodynamic loudspeaker is connected to the input of the multiplier via an additional dynamic, non-linear transmission element, the output of the linear, dynamic transmission element is connected in series to the other input of the multiplier via a downstream memoryless, non-linear transmission element (N), the output of the multiplier is connected another linear, dynamic transmission element, which is a differentiator in the case of equalization of an electrodynamic speaker, with the first input of an adder (103), the second input of the adder (103) with the input (21) (E₁) and the output of Addi erers (103) with the output (25) (A) of the Dreitor (D) are interconnected. Arrangement according to claim 2,

characterized,

that the input (22) (E₂) of a Dreitor (D) via a dynamic transmission element, via a downstream memoryless, non-linear transmission element (N) and via a downstream, further, linear and dynamic transmission element in series with an input of an adder (103) is connected and the second input of the adder (103) with the input (21) (E₁) of the three-way sensor (D) and the output of the adder (103) with the output (25) (A) of the three-way device (D) are connected together. Arrangement according to one or more of claims 3 to 8,

characterized,

that in the electrodynamic sound transmitter the three-port (D _B ) for compensation of the electrodynamic drive is connected in chain with the other three-portors in such a way that the three-port (D _L ) for compensation of the inductance compensation at the output of the three-port (D _B ) and all other three-port inputs are connected to the three port (D _B ). Arrangement according to one or more of claims 3 to 8,

characterized,

that for simultaneous compensation of the deflection-dependent, electrodynamic coupling parameter and further transducer parameters of the electrodynamic sound receiver, the three-port (D _BE ) for compensation of the coupling parameter is connected to the output of the microphone (3) or an immediately connected microphone amplifier (7) and that the output of the three-way ( D _BE ) is connected in series with another non-linear dynamic two-port, which contains the compensation three-ports for the further converter parameters. Arrangement according to claim 1,

characterized,

that the adapter consists of a generation part for generating an excitation signal and an analysis part for recording and evaluating a measurement signal, the generation part is connected to the converter and / or to the non-linear equalizer network and the analysis part to form a measuring chain, an electrical or mechanical or acoustic signal is measured on the converter by the analysis part, the output of the analysis part is connected to the control input of the equalizer network and the transmitted control signals change the parameters of the linear and non-linear transmission elements of the equalizer network and adapt them automatically to the converter.

Images