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    • 专利摘要:
    The present invention relates to a circuit for supplying acoustic signals of at least one loudspeaker (HP), this circuit comprising a resonance peak filtering device occurring at a certain frequency of the supply current, characterized in that the peak filtering device is incorporated in a first intermediate branch branch of the intermediate circuit between at least two converters (A, AO), this filtering device being purely electric in the form of a connected impedance (Z3), on the one hand, at a point of the intermediate circuit and, on the other hand, to an instrumentation mass, the impedance being said RLC (Z3) comprising at least a first resistor (R3), at least a first capacitor (C3 ) and at least a first inductance (L3) arranged in series, the parameters of the first resistor (R3), the first capacitor (C3) and the first inductance (L3) being predetermined as a function of the resonance peak at filter.
    公开号:FR3018419A1
    申请号:FR1400581
    申请日:2014-03-05
    公开日:2015-09-11
    发明作者:Etienne Gaviot；Mehran Erza；Frederic Polet；Lionel Camberlain；Romain Ravaud
    申请人:Commissariat a lEnergie Atomique CEA；Universite du Maine；Whylot SAS；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    [0001] The present invention relates to a device and a method for filtering the resonant peak in a circuit of at least one loudspeaker upstream thereof. supplying at least one loudspeaker, the filtering device being arranged upstream of said at least one loudspeaker.
    [0002] It is known that a conventional loudspeaker comprises an electromagnetic actuator, most often composed of a coil disposed on a moving element within a magnetic field generated by a permanent magnet. When the winding of the loudspeaker is traversed by a frequency-modulated current, the audible frequency induced mechanical displacement is transformed into an acoustic field by means of a membrane acting as an emitting surface, also called an acoustic radiator. The sound quality of the loudspeaker depends on the frequency response curve, that is to say a mechanical response in acceleration to an electrical stress either current or voltage, which one seeks the most constant possible on the overall bandwidth. The sound quality also depends on the linearity of the device marked by the presence of a minimum of harmonic distortions and intermodulations. If the transducer acting as a speaker favors all frequencies equally, the reproduction of the timbre of a musical instrument, constituting the useful harmonics of the sound, seems a priori to be assured. However, the reality is more complex, given the need to adequately reproduce the attack transients sounds representative of the acoustic signature of quality instruments. The response of the speaker to the transients is an essential condition of "fidelity" that can be tested by detecting the "drag" of the membrane when the loudspeaker is solicited by a train of pulses. The inertia of the moving equipment and the forces due to the phenomena of self-induction contribute to this defect. The acoustic, optical and electrical measurements show that there is no ideal loudspeaker and that each embodiment has defects in terms of bandwidth limitation, various resonance peaks and inertia. The coupling of several transducers in principle makes it possible to overcome many defects, but, conversely, it sometimes happens to see the accumulated defects unacceptably for a quality musical reproduction. In a loudspeaker, the useful motive force at the origin of the displacement of the moving element results from the interaction of the magnetic induction field, denoted B, with each element of length of the coil traversed by a current noted i ( t) function of a time t. At the local level, the elementary force applied to a load carrier moving within an induction field is called a Lorentz force and is exerted in a direction perpendicular to the plane defined by the field and the speed of the carriers. . A balance within a charge-bearing elementary volume subject to the phenomenon leads to the expression: F = i.fo B.d1- (1) It is as if the unrolled length of the winding, denoted I, was exposed to a homogeneous magnetic field of induction, which makes it possible to define the quantity BI = BI called factor of force (in Newton per Ampère or in Tesla.mètre) of the driving part of the loudspeaker. This force, modulated by the intensity, solicits the mobile equipment whose mechanical behavior is dictated by three components: a force of inertia, product of the mass of moving parts denoted NA, by the acceleration imposed, a force of damping, generally considered proportional to the speed of movement via a constant noted fm in newton / m / s or kg / s and a restoring force linked the suspension mechanism with a stiffness noted km in N / m. For a guided translation on an x axis, the equation of behavior of such an idealized transducer can be written: F = 131.i = Mmdt + d2 x dx Îm + km.x (2) The current-voltage relation across the loudspeaker is governed by its structure characterized by moving moving equipment within a magnetic field. Thus, the electrical behavior is dictated by two mechanisms, namely the Joule effect dissipation related to the Ohm's law and the electromagnetic interactions in terms of induced electromotive forces, underpinned by three contributions: - the voltage drop related to the resistive component of the solenoid winding of the crew, - the induced electromotive force related to the variation of the magnetic flux during displacement, - the electromotive force of self-induction governed by the Lenz law. Thus, in the assumption of linearity of the system, to the aforementioned equation governing the mechanical behavior of the loudspeaker, an equation of electrical behavior is added: di dx (3) em = Re-r + -dr + 1 dt For which Re is the pure resistive component of the winding, likely to vary with the temperature measured in Ohms and its own inductance function of the displacement measured in Henry when nonlinearities are taken into account. In fact, if the current involved in the left-hand side of the second equation flows directly from the third equation, then any perturbation or non-linearity involved in the latter leads to an influence on the displacement of the membrane and its derived functions. There are two respective strategies for controlling a loudspeaker, namely current control or voltage control. If, in both cases, the signal processing by the pre-amplification stages leads to a systematically measurable control signal in the form of a voltage, in the case of a voltage control, it is naturally dependent the impedance of the dipole represented by the transducer acting as speaker. This pilot is akin to a connection between ideal Thevenin generators on the speaker. The loudspeaker then constitutes a load dependent on a quasi-zero impedance supply and any generated electromotive force or f.e.m component directly influences the current flowing through the association. Conversely, for current control, the current voltage transduction is provided by a specifically arranged signal conditioner, the transducer being biased by the output current of this conditioner. This control is comparable to an ideal Norton generator on the transducer: the latter then represents a load solicited under infinite impedance, on which any fluctuation of f.e.m. generated by the charge has no effect on the behavior of the association. More preferably, this voltage can be measured and then used as a correction signal in a servo strategy. In general, control by voltage command directly solicits the speakers, given an electrical behavior subject to the parameters of its impedance. It is only relatively recently that various works have been carried out for the design of specifically-driven loudspeakers, taking into account adequate conditioners. Among the electrical and mechanical parameters representative of the behavior of a loudspeaker, the three quantities BI, Re, Le previously mentioned fundamentally determine the quality of reproduction of the conditioner and transducer association. The interactions will not be the same depending on the choice made by the designer among the two modes of current and voltage control.
    [0003] During current steering, the conditioner-transducer association remains by nature totally immune to the generated voltages. For such a choice, however, it is necessary to detect and correct, if possible, the defects inherent in the alteration of the parameters involved in equation (2) which in fact presents a parasitic force term depending on the intensity squared or i2 so-called solenoid according to the formula: 1 2 dL dx (4) B, -i + - = M d2x + .1 .-- + k.-x '2 dx dt2 dt Equation (2) can be written in the frequency domain by: [B, .I - = M..p2 - X + f..pX + k..X = M .. p2 + fm .p + km X (5) MM where X denotes the displacement transform according to Laplace and I denotes 1 unit, the ratio fn -, / M, being representative of the attenuation which is the inverse function of the relaxation time, whereas km / Mm is the square of the resonant angular frequency. Noting fm / Mm = 2 / 'r and km / M,' = wo2, where wo is the initial angular velocity, the transfer function of displacement relative to the current is expressed: XB, 1 B, 1 _ B1 1 (6 ) M. (p2 +2 .p + do) M. (pa). (Pb) M. P, r Equations (2) and (3) can be considered in the frequency domain in the harmonic regime and combined with one another in the frequency domain. terms of cascaded transfer functions. Noting E0 and lo the decoupled complex quantities of their evolutionary part, the index being significant of a particular angular frequency also called "phasors" in English, one obtains: E, = I, - (Re + Le - p) + BI. (X - p) Bi - Io = Mm - p - (p X) + f ', - (p - X) + - (p - X) let (p - X) B, - mn, - p + f', + -km After substitution of the product pX in the first relation, the impedance transfer function immediately appears in a composite form involving two terms: P (7) Io Mm 1.2+ m p + mmj km If the reactance component is neglected, then the impedance of the loudspeaker can be written: Z'Re + B, 2 p Re-Mm- Pi + B, 2 .p / 1/1, n Pi M ', Pi The grouping of the parameters then leads to the following simple form: [X1 B1 1 B, 1 (7b) Ejp, Mm-R, [2 + Vm + 1113; 21Rej p + 4 -11 / 1.'Re It immediately appears that the polynomial V1 which is the one Representative of the behavior related to voltage control is characterized by a depreciation a fortiori more marked than that of the polynomial P1 associated with the current control regime. The coefficient of viscous friction fm of a current control regime is substituted for a voltage control regime with a systematically increased coefficient such that fm + e (fm + B, 2 I Re)> fm (8). eigen times involved (s ', and tm + e), mechanical resonance factors Q are defined, and such that: ^ B, 2 E ° = Z' = (Re + Le- p) + (7a) Qm_ (00 - rm = .jkm-Mm and = lk .114- t Qm + e = Mm 2 2 fm + B12 / Re (9 and 9a) A specific electrical coefficient Qe can therefore be defined by making fr ,, vers zero and a simple relation coupling the resonance factors can then be written: 1 1 1 - + - = Qm + e Qm Qe The impedance of the transducer combines an exclusively electrical component with a second component called motional impedance. Speaker impedance ZHP is written ZHp = Zr, where: Ze = (Re + Le - p), and z = B12 B12 p (11, 11a) Mm (122+ f ', p + km1 P1 MM) appears that the emotional impedance is affe next to a characteristic two-order polynomial marking a band-pass behavior. Moreover, if the use designates the nominal value of the impedance by a given value, often 4W and 8W for the power transducers, 16W and 32W for the mini and microsystems equipping the helmets, the contribution of the emotional impedance n is in no way negligible when the transducer must be stressed.
    [0004] Likewise, when the frequency increases, the inductive reactance component j.L.w gradually attenuates the reproduction of the signals. The behavior of a voltage-biased transducer shows the coupling of the associated relations 8 and 9b in terms of composite transfer functions. Considering here the function relating to the displacement X (p), by taking again the previous notations of the equation (6): ll [X] = B, 1 with P1 = p2 + -2 .p + co2 0 Mm The equation ( 11) describing the impedance of the transducer furthermore entails: [X] _ [X] [I] E p I p - E p M. PI Z 'Accordingly, the functions of transfer of the speed of the diaphragm and the 'acceleration, in terms of derived quantities, are then expressed in two equations: [V1 p 1 and [-Al = B1 P2 1 LE p Mm PI Z' EJ pMm P1 Z '(10) (12) (12 & 12a) If we consider the function relating to the displacement, it can be expressed in a general way in the following form: [xi B1 1 1 B1 1 1 (13) LEI, M. P1 Z 'M. P' V B2 p e + Le- p) + M ', P, An important consequence of this writing appears immediately, when one is interested in regimes close to resonance, with the necessity of a correction by filtering in the case of current steering. The voltage control allows for it to benefit from a significant advantage, often cited as a definitive argument justifying this choice, with a much greater natural damping effect than for a current control.
    [0005] Document FR-A-2 422 309 recognizes in its introductory part that for a current-driven loudspeaker the speaker membrane may be the seat of deformation or very high frequency stationary waves, which is particularly disadvantageous for current steering. Conversely, this document recognizes that voltage control can only be used in a restricted frequency domain. To improve the current control, this document proposes to combine a current command and an acceleration servo for the frequency range covering all the mechanical resonances of the loudspeaker. This solution has however never given satisfaction, a servocontrolled acceleration could not compensate for all the mechanical resonances specific to each speaker. Document GB-A-2 473 921 discloses in its introductory part that the sound quality of electrodynamic loudspeakers can be significantly improved by supplying a loudspeaker with current control instead of voltage control. frequently adopted. The current control is obtained when the impedance of the source seen by the pilot is high compared to the own impedance of the driver. This document also recognizes that in current driving, a typical frequency peak of a cone-shaped loudspeaker lift can not be compensated by simply adding an RC network in parallel with the driver, the high impedance of the source being lost. This document therefore proposes a control of the loudspeaker with a double coil used together with an impedance which deactivates one of the acoustic coils at high frequencies, which produces the correction of the required response while maintaining a relatively high impedance of the source. The addition of a double coil however requires a complete reconstruction of the current control coil which is not usually double. This presents a cost of crippling design and specific arrangements for current steering. In accordance with the two documents of the state of the art mentioned above, while the advantages of running a loudspeaker have been recognized, solutions have not been developed to date effectively remedy two major endemic drawbacks of such current control, namely: - on the one hand, the presence of a resonance peak that can not remain without being corrected, while a voltage control brings precisely a natural correction for this resonance peak thanks to the effects of the motional impedance set at the resonant frequency of the transducer, - on the other hand, when the frequency increases, acoustic studies show an increased directivity effect from the top speaker leading to an increase in measurable sound level in the axis perpendicular to the diaphragm, this phenomenon bearing the English name of "horn effect". Again, during voltage control, the inductive component of the transducer locally corrects this effect before reducing the acoustic level in the higher frequencies. The aim of the present invention is, for any category of loudspeaker, to correct at least the presence of a resonance peak during a driving current of the loudspeaker, this by electronic means and without specific adaptation of the current control of the speaker which remains unchanged from that of the state of the art. For this purpose, the invention relates to a circuit for supplying acoustic signals of at least one loudspeaker, this circuit comprising a resonance peak filtering device occurring at a certain frequency of the supply current of the at least one a loudspeaker and at least two non-inverter converters arranged in series upstream of said at least one loudspeaker, each of the two converters having a positive power supply terminal and a negative power supply terminal and an output, the most upstream of the two converters having its positive power supply terminal connected to the input power supply of the circuit while its output is connected by an intermediate circuit to the positive power supply terminal of the second converter, the output of the second converter being connected auditing at least one loudspeaker, characterized in that the resonant peak filtering device of said at least one loudspeaker is incorporated in a first e branch bypassing the intermediate circuit between said at least two converters, this filtering device being purely electrical in the form of an impedance connected, on the one hand, to a point of the intermediate circuit and, on the other hand, to a instrumentation mass, the impedance being said RLC comprising at least a first resistance, at least a first capacitor and at least a first inductance arranged in series, the parameters of the first resistor, the first capacitor and the first inductance being predetermined according to the resonance peak to be filtered from said at least one speaker. The technical effect is to be able to use current control with the aforementioned advantages while obscuring at least the major disadvantage of current steering which is the formation of a resonance peak not compensated by a current control contrary to a voltage control.
    [0006] Advantageously, the first inductor is virtual by being formed of two non-inverter auxiliary converters disposed in series, each of the two auxiliary converters having a positive power supply terminal and a negative power supply terminal and an output, the most upstream of the two auxiliary converters having its positive supply terminal connected to the output of the first capacitor while the output of this upstream auxiliary converter is connected by a first intermediate auxiliary circuit to the positive supply terminal of the second auxiliary converter, the first intermediate auxiliary circuit having an auxiliary capacitor and being connected in shunt to an instrumentation ground auxiliary circuit having a first auxiliary resistor, the output of the second auxiliary converter being connected to the first auxiliary converter by a second auxiliary circuit comprising and a second auxiliary resistor, each auxiliary converter having its own feedback loop connecting its output to its negative power supply terminal. A virtual inductor is particularly advantageous because it can be easily modified without changing the elements that compose it but only in their interaction and / or operation. Such a virtual inductor has the great advantage of easy adaptation to the operating conditions of said at least one loudspeaker, in particular but not only for monitoring a variation in the frequency of the resonance peak due for example to a variation of temperature of said at least one speaker or against overheating of said at least one speaker.
    [0007] Advantageously, the first virtual inductance is equal to the product of the first and second auxiliary resistors and the auxiliary capacitor. Advantageously, the first resistor and the second auxiliary resistor deduce from each other a total resistance according to the equation: R3 = R03 RA Advantageously, a second capacitor is disposed in a second branch bypassing the intermediate circuit between said at least two converters, this second capacitor being associated with a second resistor, the parameters of the second resistor and the second capacitor being predetermined for attenuation of the high frequency signals. Advantageously, the intermediate circuit between the two non-inverting converters comprises a third resistor disposed between the output of the most upstream non-inverting converter and the first branch branch of the intermediate circuit incorporating the filtering device.
    [0008] Advantageously, for a resonance peak frequency of 197 Hz, the value of said at least one first resistor is equal to 0, the values of said at least one first capacitor and said at least one first inductance are equal to 0.29 pF, respectively. and 2.28 H, the values of the first auxiliary resistor and the second auxiliary resistor being respectively equal to 1.20051 and 40052, the value of the third resistor being equal to 3.000 Ω. Advantageously, each non-inverting converter has its own feedback loop connecting its output to its negative power supply terminal, each of the feedback loops being mounted, for the most upstream converter, as a bypass of the intermediate circuit between the two non-inverter converters. and, for the most downstream converter, bypassing an instrumentation ground circuit disposed after said at least one loudspeaker, the instrumentation ground circuit having a fourth resistor. The invention also relates to a method for controlling the electrical power supply of acoustic signals of at least one loudspeaker, the power supply incorporating such a resonance peak filtering device, in which method it is carried out step of correcting the resonance peak by the filtering device, this step being upstream of said at least one speaker. Advantageously, the overall resonance factor of the loudspeaker and the filtering device takes the value of a Butterworth filter.
    [0009] Advantageously, when said at least one loudspeaker comprises a diaphragm, the resonance peak is simultaneously filtered at a reduction in the acoustic level in the highest frequencies in the direction of the perpendicular axis of the diaphragm of said at least one loud speaker.
    [0010] Advantageously, the temperature variations of said at least one loudspeaker are taken into account by the filtering device by variation in correspondence of the impedance parameters of said device. Current control does not regulate a possible overheating of said at least one speaker unlike a voltage control. This may be a disadvantage in addition to the two disadvantages mentioned above, namely the formation of an uncompensated resonance peak and the increase of the acoustic level in the highest frequencies in the direction of the perpendicular axis of the diaphragm of said at least one speaker. In addition, the frequency of the resonance peak may vary with a change in speaker temperature. It is therefore advantageous to take into account the temperature variations of said at least one speaker especially during the correction of the resonance peak. All this can be compensated by a modification of the parameters of the impedance of the filtering device, in particular the inductance which can be a virtual inductor. In this case, taking into account the temperature of said at least one loudspeaker that can be measured or estimated is automatically done by respective modification of the various elements that form the virtual inductor, for example but not limited to auxiliary converters.
    [0011] Other advantages and particularities of the invention will appear on reading the detailed description of implementations and non-limiting embodiments, and the following appended drawings: FIG. 1 illustrates a schematic representation of a circuit of FIG. supplying acoustic signals from at least one loudspeaker, said circuit being provided with a resonance peak filtering device according to one embodiment of the present invention; - FIG. 2 illustrates an embodiment of the filtering device of the acoustic signal supply circuit represented in FIG. 1, for which the inductance of the filtering device is in the form of a virtual inductor, the virtual inductance being shown enlarged in this figure with respect to FIG. FIG. 3 illustrates for the embodiment shown in FIG. 2, the impedance comprising a virtual inductor, FIG. 4 illustrates the accelerating modules. during a current control with or without resonance peak filtering and during a voltage control of a loudspeaker, the filtering taking place with a filtering device according to the embodiment of the invention. FIG. 5 illustrates angle-angle curves as a function of frequencies, the filtering taking place with a filtering device according to the embodiment of the invention shown in FIG. 1.
    [0012] According to the present invention, an ideal current control solution would seek to find a filtering mode for filtering the two previously mentioned effects, namely the resonance peak and the directivity effect of the speaker without altering the index. current control also known as CDI. However, it is possible to filter only the resonance peak according to the present invention while optimally retaining the current control index. This rules out any filter structure arranged in parallel with the loudspeaker because of the finite impedance character, or even the low value seen in terms of the source according to Thévenin, which is likely to alter the CDI index in a crippling manner on a part of useful spectrum. As the correction of the resonance peak is apparent from the intrinsic behavior of the transducer, the present invention proposes a passive correction solution upstream of said at least one loudspeaker.
    [0013] The invention therefore relates to a method for controlling the current of the electrical power supply with acoustic signals from at least one loudspeaker, the power supply incorporating a resonance peak filtering device, in which a step is performed. resonant peak correction by the filtering device, this step being upstream of said at least one speaker.
    [0014] The intrinsic advantage of the correction mode upstream of the loudspeaker or a priori correction, also called "feedforward correction" in English, is to guarantee the non deterioration of the control index in current or CDI vis-à-vis the piloting the speaker. Advantageously, when said at least one loudspeaker comprises a diaphragm, the resonance peak is simultaneously filtered at a reduction in the acoustic level in the highest frequencies in the direction of the perpendicular axis of the diaphragm of said at least one loud speaker. In the embodiment of the acoustic signal supply circuit, this reduction is ensured by a resistance and capacitor system branched into the main circuit as will be developed later.
    [0015] Advantageously, the overall resonance factor of the loudspeaker and the filtering device takes the value of a Butterworth filter, which will also be developed later. According to the present invention and with particular reference to FIGS. 1 to 3, the acoustic signal supply circuit of at least one HP loudspeaker according to the present invention has a resonance peak filtering device. The circuit also comprises at least two non-inverter converters A, Ao arranged in series upstream of said at least one loudspeaker HP, each of the two converters A, A0 having a positive power supply terminal and a negative power supply terminal. 'output.
    [0016] The upstream A of the two converters A, A0 has its positive supply terminal connected to the input power supply of the circuit while its output is connected by an intermediate circuit to the positive supply terminal of the second converter Ao. The output of the second converter A0 is connected to said at least one speaker HP, a resonance peak occurring at a certain frequency of the supply current of said at least one speaker HP. The essential characteristic of the circuit is that the resonant peak filtering device of said at least one speaker HP is incorporated in a first branch branch of the intermediate circuit between said at least two converters A, A0. This filtering device is purely electric and is in the form of an impedance Z3 connected, on the one hand, to a point of the intermediate circuit and, on the other hand, to an instrumentation mass. The impedance Z3 is said to be RLC comprising at least a first resistor R3, at least a first capacitor C3 and at least a first inductance L3 arranged in series. The parameters of the first resistor R3, the first capacitor C3 and the first inductance L3 are predetermined as a function of the resonance peak to be filtered from the at least one speaker HP. Advantageously, the first inductance L3 is virtual, that is to say that the first inductance L3 may for example be formed of a system of active circuits acting as inductance. Such a correction envisaged is predefined to the first order and a filtering solution upstream of said at least one speaker HP, also known under the name of "feedforward correction", can therefore be developed with components of medium power, currents remaining below 50mA, replacing the inductor with the active circuit system. For the embodiment using virtual inductance, the fundamental advantage of the filtering arrangement upstream of the voltage current converter appears in the low values of the intensity involved in the filtering operation, thus allowing the use of numerous references. of very low noise operational amplifier components to form the virtual inductor. High-performance filtering devices with low noise and no copper winding can therefore be developed.
    [0017] Eventually, this embodiment with a virtual inductor can allow self-adapting the filtering device during operation to correct any drift related to a possible change in the HP speaker environment. This can result in particular automatic compensation of the offset of the resonant frequency due to the heating of the speaker HP. The approach then participates in a feedback loop coupling with the electrical control upstream of the filtering device. Advantageously, the active circuit system is formed of two auxiliary converters A112, A2 / 2 non-inverters arranged in series. Each of the two auxiliary converters A112, A2 / 2 has a positive power supply terminal and a negative power supply terminal and an output. The most upstream A112 of the two auxiliary converters A112, A2 / 2 has its positive supply terminal connected to the output of the first capacitor C3 while the output of this upstream auxiliary converter Al2 is connected by a first intermediate auxiliary circuit. to the positive power supply terminal of the second auxiliary converter A212. The first intermediate auxiliary circuit comprises an auxiliary capacitor CA and is connected in shunt to an auxiliary instrumentation ground circuit having a first auxiliary resistor RB. The output of the second auxiliary converter A2 / 2 is connected to the first auxiliary converter A112 by a second auxiliary circuit having a second auxiliary resistor RA, each auxiliary converter A112, A212 having its own feedback loop connecting its output to its negative supply terminal . Advantageously, for the elements of the impedance Z3 satisfy a compromise between a minimum noise and currents maintained at low values, for example a current intensity in the impedance Z3 of less than 5 mA.
    [0018] The first virtual inductance L3 may advantageously be equal to the product of the first R3 and second auxiliary resistor RA and the auxiliary capacitor CA. In a preferred embodiment, a second capacitor Ch may be disposed in a second branch bypassing the intermediate circuit between the at least two converters A, A0. This second capacitor Ch is associated with a second resistor Rh, the parameters of the second resistor Rh and the second capacitor Ch being predetermined for the attenuation of the signals in high frequency with an effective internal time Rp.Ch. The second resistance Rh and the capacitance of the second capacitor Ch can be respectively Rh-1 12 and Ch -4.7 nF. This is however purely indicative. Current control is known not to cause attenuation in high frequency, unlike voltage control where the inductive component of the speaker naturally decreases the signal level. It therefore proves expedient to provide current control with forced attenuation at high frequency, in particular with respect to the increased directivity effect of the loudspeaker leading to a measurable sound level increase in the axis perpendicular to the diaphragm. Advantageously, the intermediate circuit between the two non-inverting converters A, A0 comprises a third resistor Rp disposed between the output of the non-inverter converter A most upstream and the first branch branch of the intermediate circuit incorporating the filtering device. Advantageously, each non-inverting converter A, A0 has its own feedback loop connecting its output to its negative power supply terminal, each of the feedback loops being mounted, for the most upstream converter A, in shunt of the intermediate circuit between the two non-inverting converters A, A0 and, for the most downstream converter A0, in derivation of an instrumentation ground circuit arranged after the loudspeaker HP, the instrumentation mass circuit comprising a fourth resistor R61.
    [0019] Let V3 and V1 be the voltages as indicated in FIG. 1, V3 being the voltage between the branch point of the first branch of the resonance peak filtering device with respect to the intermediate circuit and an instrumentation mass and V1 being the voltage between the output of the first auxiliary converter A upstream and an instrumentation mass, a conventional calculation makes it possible to obtain the transfer function V3 / V1 of the filter formed by the serialization of Rp and of the series network R3L3C3 either: V3 p2 + (R310.p + 1x3.c, V1 p 2 + R3 + RP p + 114c3 L3 Thus, the filtering performed, possibly combined with the high frequency attenuation by the filter Rh, Ch makes it possible to keep only the current conditioner function assigned to the power amplifier and charging on said at least one speaker HP The specificity of this conformation lies in the virtual constitution of the inductor L3 using two active components. considering the impedance presented by the assembly RA, RB, CA, A, Ao, the following two relations can be combined: [Ua RB and I = -U a (14 & 14a) L u R + 1 RA B The identification of the elements then leads to an impedance behavior such that: ## EQU1 ## or self of value L3 = RA.RB.CA, put in series with resistance RA. It is possible to establish a relation giving R3 as a function of RA with R3 = R03 -RA. The arrangement of the chosen parameters makes it possible not to have to mount this component, the series value of RA having almost the required value to ensure the desired attenuation, 1 / C), as mentioned in equations (9) and (10). ). Indeed, if: RA 1 then, RA = RP (16) Q. RA + Rp Qm -1 Advantageously, it is possible to define a global resonance factor taking as optimal value, that of a filter according to Butterworth, which corresponds to QHP + z3 = 1k2. Starting from the preceding equations, it is possible to proceed to the selection of the values of the following parameters: Q3 = I - 0.856 It3 + R 'C3 10o = .c, 1 - 416 rad / sec Figure 4 illustrates the module curves of the acceleration for current control with or without resonance peak filtering as well as the acceleration module for voltage control of said at least one loudspeaker, the filtering taking place with a filtering device according to the form of embodiment of the invention illustrated in FIGS. 1 to 3. The current control curve without filtering is that with rectangles, the current control curve with filtering is with circles and the voltage control curve is that with diamonds. .
    [0020] The intermediate curve with rectangles is the curve with current control and filtering with a filtering device according to the first embodiment and shows the absence of a resonance peak unlike the upper curve with current control without filtering. In addition, this intermediate curve has a substantially constant acceleration modulus range wider than that of the lower curve which is the curve with voltage control with diamonds. It turns out that the modulus of the acceleration with a resonance peak thus filtered has a satisfactory behavior if it is considered as not penalizing the addition of two active circuits with two auxiliary converters for obtaining a virtual inductor. a value close to L3 = 6 H.
    [0021] FIG. 5 illustrates the angle degree curves as a function of the frequencies, the filtering taking place with a filtering device according to the embodiment of the invention shown in FIGS. 1 to 3, for the speaker phase or HP defined by the curve carrying rectangles and for the phase V3 N1 defined by the curve bearing circles.
    [0022] The curves of FIG. 5 show that the phase shift angle remains in a range of perfectly acceptable values over the frequency domain considered. In a preferred application of the present invention, moderate capacitance values of the order of the microfarad permit the implementation of polypropylene MKP capacitors, which capacitors are well suited to transient conditions. A non-limiting example will now be given for a loudspeaker having the following characteristics B1 = 2.675 Tm, Mm = 3.67 g, fm = 0.539 N / m, km = 5650 N / m, resonance frequency = 197 Hz, Re = 3.6552, L = 0.12 mH. For such a loudspeaker, the following values can be selected for the various elements of the circuit according to the present invention, R3 = 0 £ 2, C3 = 0.29 NF, Rp = 3 kn, and L3 actively reproduced with RA = 40051, RB = 12000, CA = 4.7pF, or L3 equivalent to 2.28 H. In what has been previously described, at least one non-inverting converter has been used in the circuit, this for simplification of calculations . This is not limiting and the present invention can however also apply for a circuit comprising one or more inverters. The market for audio reproduction, particularly high-end reproduction, is directly concerned with the filtering devices according to the present invention. The major brands, such as Boose®, Bang & Olufsen®, Harman Kardon®, B & W®, etc., could be of interest for the commercial distribution of such filtering devices.
    权利要求:
    Claims (12)
    [0001]
    REVENDICATIONS1. Acoustic signal supply circuit of at least one loudspeaker (HP), said circuit comprising a resonance peak filtering device occurring at a certain frequency of the supply current of said at least one speaker (HP ) and at least two non-inverting converters (A, Ao) arranged in series upstream of said at least one loudspeaker (HP), each of the two converters (A, Ao) having a positive power supply terminal and a terminal of negative power supply and an output, the most upstream (A) of the two converters (A, A0) having its positive power terminal connected to the input power supply of the circuit while its output is connected by an intermediate circuit to the positive supply terminal of the second converter (A0), the output of the second converter (A0) being connected to the at least one speaker (HP), characterized in that the resonance peak filtering device of the at least one a speaker (HP) is i incorporated in a first branch bypassing the intermediate circuit between said at least two converters (A, A0), this filtering device being purely electrical in the form of an impedance (Z3) connected, on the one hand, to a point of the intermediate circuit and, on the other hand, to an instrumentation mass, the impedance being RLC (Z3) comprising at least a first resistor (R3), at least a first capacitor (C3) and at least a first inductor (L3) arranged in series, the parameters of the first resistor (R3), the first capacitor (C3) and the first inductance (L3) being predetermined as a function of the resonance peak to be filtered from the at least one loudspeaker (HP ).
    [0002]
    2. Circuit according to the preceding claim, wherein the first inductor (L3) is virtual being formed of two auxiliary converters (A112, A2,2) non-inverters arranged in series, each of the two auxiliary converters (A112, A212) having a positive supply terminal and a negative supply terminal and an output, the most upstream (A1,2) of the two auxiliary converters (A112, A2 / 2) having its positive supply terminal connected to the output of the first capacitor (C3) while the output of this most upstream auxiliary converter (A112) is connected by a first intermediate auxiliary circuit to the positive supply terminal of the second auxiliary converter (A212), the first intermediate circuit having a capacitor (AC) and being branched to a first instrumentation ground auxiliary circuit having a first auxiliary resistor (RB), the output of u second auxiliary converter (A2,2) being connected to the first auxiliary converter (Al2) by a second auxiliary circuit comprising a second auxiliary resistor (RA), each auxiliary converter (Al2, A2,2) having its own feedback loop connecting its output to its negative power terminal.
    [0003]
    3. Circuit according to the preceding claim, wherein the first virtual inductor (L3) is equal to the product of the first (RB) and second (RA) auxiliary resistors and the auxiliary capacitor (CA).
    [0004]
    4. Circuit according to the preceding claim, wherein the first resistor (R3) and the second auxiliary resistor (RA) are deduced from each other of a total resistance (R03) according to the equation: R3 = R03 RA
    [0005]
    5. Circuit according to any one of the preceding claims, wherein a second capacitor (Ch) is disposed in a second branch bypass of the intermediate circuit between the at least two converters (A, A0), the second capacitor (Ch) being associated with a second resistor (Rh), the parameters of the second resistor (Rh) and the second capacitor (Ch) being predetermined for the attenuation of the high frequency signals.
    [0006]
    6. Circuit according to the preceding claim, wherein the intermediate circuit between the two non-inverter converters (A, A0) comprises a third resistor (Rp) disposed between the output of the noninverter converter (A) the most upstream and the first branch. bypassing the intermediate circuit incorporating the filtering device.
    [0007]
    7. Circuit according to the preceding claim, wherein for a resonance peak frequency of 197 Hz, the value of said at least one first resistor (R3) is equal to 0, the values of said at least one first capacitor (C3) and of said at least one first inductance (L3) is respectively equal to 0.29 pF and 2.28 H, the values of the first auxiliary resistor (RB) and the second auxiliary resistor (RA) being equal to 1.2000 and 4000 respectively, the value of the third resistance (Rp) being equal to 3.0000.
    [0008]
    8. Circuit according to any one of the preceding claims, wherein each non-inverting converter (A, A0) has its own feedback loop connecting its output to its negative power supply terminal, each of the feedback loops being mounted, for the most upstream converter (A), in bypass of the intermediate circuit between the two non-inverting converters (A, A0) and, for the most downstream converter (A0), in derivation of an instrumentation earth circuit arranged after said at least one speaker (HP), the instrumentation ground circuit having a fourth resistor (RO.
    [0009]
    9. A method for controlling the electrical power supply of acoustic signals of at least one loudspeaker (HP), the power supply incorporating a resonance peak filtering device according to any one of the preceding claims, in which which method is carried out a step of correction of the resonant peak by the filtering device, this step being upstream of said at least one speaker (HP).
    [0010]
    10. Control method according to the preceding claim, wherein the overall resonance factor (QHP + z3) of the loudspeaker and the filtering device takes the value of a Butterworth filter.
    [0011]
    11. Control method according to any one of the two preceding claims, wherein, when said at least one speaker (HP) comprises a diaphragm, it is simultaneously filtered resonant peak at a reduction of the acoustic level in the highest frequencies in the direction of the perpendicular axis of the diaphragm of said at least one speaker.
    [0012]
    12. Control method according to any one of the three preceding claims, wherein the temperature variations of said at least one speaker (HP) are taken into account by the filtering device by variation in correspondence of the impedance parameters. (Z3) of said device.30
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    BE350502A|
    同族专利:
    公开号 | 公开日
    CN106063294A|2016-10-26|
    WO2015140421A1|2015-09-24|
    JP6452207B2|2019-01-16|
    FR3018419B1|2017-06-23|
    US20170171660A1|2017-06-15|
    EP3114856A1|2017-01-11|
    US10271139B2|2019-04-23|
    JP2017512023A|2017-04-27|
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    法律状态:
    2015-03-16| PLFP| Fee payment|Year of fee payment: 2 |
    2016-03-10| PLFP| Fee payment|Year of fee payment: 3 |
    2017-04-27| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1400581A|FR3018419B1|2014-03-05|2014-03-05|DEVICE AND METHOD FOR FILTERING THE RESONANCE PIC IN A POWER SUPPLY CIRCUIT OF AT LEAST ONE SPEAKER BEFORE THE SAME|FR1400581A| FR3018419B1|2014-03-05|2014-03-05|DEVICE AND METHOD FOR FILTERING THE RESONANCE PIC IN A POWER SUPPLY CIRCUIT OF AT LEAST ONE SPEAKER BEFORE THE SAME|
    CN201580011366.1A| CN106063294A|2014-03-05|2015-03-03|Device and method for filtering the resonance peak in a circuit for supplying at least one loud speaker upstream of the latter|
    JP2016554730A| JP6452207B2|2014-03-05|2015-03-03|Apparatus and method for filtering a resonance peak in a power supply circuit of at least one speaker upstream of the speaker|
    PCT/FR2015/000049| WO2015140421A1|2014-03-05|2015-03-03|Device and method for filtering the resonance peak in a circuit for supplying at least one loud speaker upstream of the latter|
    EP15714246.4A| EP3114856A1|2014-03-05|2015-03-03|Device and method for filtering the resonance peak in a circuit for supplying at least one loud speaker upstream of the latter|
    US15/127,851| US10271139B2|2014-03-05|2015-03-03|Device and method for filtering the resonance peak in a circuit for supplying at least one loud speaker upstream of the latter|
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