Method of operating an electroacoustic transducer and corresponding circuit and device

Abstract

Embodiments of the present disclosure relate to methods of operating an electroacoustic transducer and corresponding circuits and devices. An electroacoustic transducer, such as a piezoelectric micromachined ultrasonic transducer, is coupled with an adjustable load circuit having a set of adjustable load parameters including a resistance parameter and an inductance parameter. Starting from at least one resonant frequency or at least one damped natural frequency of the electroacoustic transducer, a set of model parameters is calculated for a Butterworth-Van Dyke (BVD) model of the electroacoustic transducer. The BVD model includes an equivalent circuit network having a constant capacitance coupled to an RLC branch, and the adjustable load circuit is coupled with the electroacoustic transducer at an input port of the equivalent circuit network of the model of the electroacoustic transducer. The adjustable load parameters are adjusted in accordance with the set of model parameters calculated for the BVD model of the electroacoustic transducer to increase a bandwidth or sensitivity of the electroacoustic transducer.

Description

Technical Field

[0001] This specification relates to electroacoustic transducers, that is, components capable of converting electrical signals into acoustic signals and / or components capable of converting acoustic signals into electrical signals.

[0002] An ultrasonic transducer is an example of such a transducer. Background Technology

[0003] Ultrasonic transducers can be considered for use in a variety of applications.

[0004] For example, they can be used in acoustic localization methods in vehicles, where (ultrasound) waves can be used to determine the distance and / or orientation of a source or reflector.

[0005] This transducer can be used in techniques based on the Doppler effect and / or measuring the time of flight (TOF) of sound waves. Examples of potential applications include obstacle detection (one-dimensional, two-dimensional, three-dimensional), volume measurement, gesture recognition, and (Doppler-based) flow metering.

[0006] Currently known as PMUT (Piezoelectric Micromechanical Ultrasonic Transducer), ultrasonic transducers are MEMS-based piezoelectric transducers (where MEMS is an abbreviation for Microelectromechanical Systems). Unlike bulk piezoelectric transducers that rely on thickness-mode motion, these MEMS-based piezoelectric transducers utilize the bending motion of a thin film coupled to a piezoelectric film.

[0007] Compared to bulk transducers, PMUTs may exhibit an underdamped mechanical response, thus involving many oscillation cycles once the membrane moves from its steady-state position back to rest; this may be due to reduced internal energy losses in the transducer (due to the miniature silicon membrane) and reduced damping imposed by the medium (air). In other words, they may exhibit a narrower bandwidth because the excitation and damping of the membrane may involve several oscillation cycles, and the possible differences in the resonant frequency of each individual membrane due to manufacturing tolerances can affect the duration, accuracy, and resolution of measurements in applications utilizing PMUTs (e.g., distance measurement).

[0008] Therefore, some advantages associated with the use of PMUT (such as small size and low drive voltage) may be adversely offset by narrower available bandwidth, dependence on manufacturing tolerances, and differences in resonant frequency.

[0009] In applications where multiple PMUTs are used (such as, for example, echolocation), mechanical crosstalk combined with narrow bandwidth can limit the ability to measure near objects because the receiver membranes (one or more) may be “blocked” by an undesirable amount of time.

[0010] Other problems may be related to undesirable spreads of certain (mechanical) parameter values ​​of different PMUTs (specifically, resonant frequencies), where low damping may further impede communication between different PMUT devices (e.g., where the transmitter and receiver cannot communicate with each other).

[0011] Italian patent application number 102019000003613 solves the problem of resonant frequency extension by utilizing the dependence of resonant frequency on voltage bias.

[0012] The various documents are examples of activities dedicated to bandwidth manipulation methods in transducers as considered in this paper.

[0013] For example, Robicchaud, A., P. Cicek, D. Deslandes, and F. Nabki's "Frequency Tuning Technique of Piezoelectric Ultrasonic Transducers for Ranging Applications," Journal of Microelectromechanical Systems 27(2018):570-579, doi:10.1109 / JMEMS.2018.2831638 discusses a low-cost technique for frequency tuning of piezoelectric micromechanical ultrasonic transducers (PMUTs), where the resonant frequencies of the first and second modes are 1.4 MHz and 5 MHz, respectively. This technique is based on a single post-processing deposition of parylene-C on all elements of the chip, thereby achieving uniform frequency tuning across all exposed elements.

[0014] In their 2008 paper "Vibration damping with negative capacitance shunts: theory and experiment" in Smart Materials and Structures (doi:10.1088 / 0964-1726 / 17 / 3 / 035015), B. de Marneffe and A. Preumont discussed the enhancement of piezoelectric stack transducers by means of the well-known 'negative' capacitance shunt, investigating two different implementations (series and parallel), with the parallel implementation applied to truss structures.

[0015] Ramos A, San Emeterio JL, and Sanz PT.'s "Improvement in transient piezoelectric responses of NDE transceivers using selective damping and tuning networks," IEEE Trans Ultrason Ferroelectr Freq Control, 2000; 47(4):826-35, doi:10.1109 / 58.852064 discusses nondestructive testing ultrasonic applications for quality control based on piezoelectric devices operating as pulsed ultrasonic probes. These piezoelectric devices typically include a tuning circuit across the pulser output connector or near the piezoelectric probe electrodes. The positive effects of certain selective damping and tuning networks on the time and frequency behavior of NDE piezoelectric transceivers are analyzed in detail.

[0016] JYMoon, J.Lee, and JHChang, in their 2016 paper "Electrical impedance matching networks based on filter structures for high frequency ultrasound transducers" in Sens.Actuators A (doi: 10.1016 / j.sna.2016.10.025), discussed the proposed electrical impedance matching (EIM) networks to achieve wide bandwidth for high-frequency ultrasound transducers and improve the signal-to-noise ratio (SNR) of ultrasound images. The EIM networks are based on general filter structures, namely, low-pass filter (LPF) structures or high-pass filter (HPF) structures composed of capacitors and inductors.

[0017] Existing solutions have drawbacks such as the following:

[0018] Increased complexity and cost, for example, due to the introduction of additional manufacturing steps;

[0019] Increased bandwidth leads to decreased sensitivity; and

[0020] Compared to its limited improvements, it is not suitable for transceiver operation and is cumbersome to set up. Summary of the Invention

[0021] Despite activities in this area, there remains interest in providing other improved solutions that can overcome the shortcomings of existing solutions.

[0022] The embodiments disclosed herein contribute to providing such an improved solution.

[0023] According to one or more embodiments, a method is provided, comprising: obtaining at least one of a resonant frequency and at least one ring-down parameter of an electroacoustic transducer having sensitivity and frequency bandwidth; calculating a set of model parameters of a Butterworth-Van Dyke (BVD) model of the electroacoustic transducer based on the resonant frequency and at least one ring-down parameter, the BVD model including an equivalent circuit network having a constant capacitance coupled to an RLC branch; coupling an adjustable load circuit to the electroacoustic transducer, the adjustable load circuit having a set of adjustable load parameters including at least one resistance parameter and one inductance parameter, wherein the adjustable load circuit is coupled to the electroacoustic transducer at an input port of the equivalent circuit network of the BVD model; and adjusting the set of adjustable load parameters based on the calculated set of model parameters of the BVD model of the electroacoustic transducer to increase at least one of the bandwidth and sensitivity of the electroacoustic transducer as a result of the adjustment.

[0024] One or more embodiments may involve corresponding circuits.

[0025] One or more embodiments may relate to a corresponding device (an acoustic position sensor module is an example of such a device).

[0026] Obstacle detection systems (e.g., for use in the automotive industry), volume measurement systems, gesture recognition systems, or flow metering systems are examples of such systems.

[0027] The claims are an integral part of the technical teachings provided herein with reference to the embodiments.

[0028] One or more embodiments can facilitate wider bandwidth while achieving or maintaining a sufficient level of sensitivity for the ultrasonic transducer. Attached Figure Description

[0029] One or more embodiments will now be described by way of example only, with reference to the accompanying drawings, in which:

[0030] Figure 1 This is a diagram illustrating the working principle of the PMUT transducer device;

[0031] Figure 2 , Figure 3A , Figure 3B , Figure 4 and Figure 5 The illustration shows a model applicable to the embodiments;

[0032] Figure 6 , Figure 7A and Figure 7B The illustrations show possible uses of the model in the embodiments;

[0033] Figure 8 Here are flowchart examples of possible actions in the embodiments;

[0034] Figure 9 These are examples of possible hardware architectures used in the embodiments;

[0035] Figure 10A and Figure 10B This is an example of a standard that can be used in embodiments to identify certain parameters of an electroacoustic transducer;

[0036] Figure 11 , Figure 12 and Figure 13 The illustration shows the embodiment. Figure 6 Possible alternatives to the model; and

[0037] Figure 14 These are examples of systems operable according to embodiments. Detailed Implementation

[0038] In the following description, one or more specific details are set forth to provide a thorough understanding of examples of embodiments described herein. These embodiments may be obtained without one or more of the specific details or by other methods, components, materials, etc. In other instances, known structures, materials, or operations have not been described in detail so as not to obscure certain aspects of the embodiments.

[0039] References to "an embodiment" or "one embodiment" within the framework of this specification are intended to indicate that a particular configuration, structure, or feature described with respect to that embodiment is included in at least one embodiment. Therefore, phrases such as "in one embodiment" or "in one embodiment" that may appear at one or more points in this specification do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, particular conformations, structures, or features may be combined in any suitable manner.

[0040] The references used in this document are for convenience only and do not limit the scope or range of protection of the embodiments.

[0041] It should be understood in another way that one or more embodiments are applied to an electroacoustic transducer, i.e., a component that can act as a transducer between the electrical and acoustic domains by converting electrical signals into acoustic signals and / or converting acoustic signals into electrical signals; that is, the term “electroacoustic” should never, or even indirectly, be interpreted as limited to converting electrical signals into acoustic signals.

[0042] Furthermore, for simplicity and ease of understanding, the exemplary description provided below refers to an arrangement including at least one of a "transmitter" segment and a "receiver" segment, wherein the "transmitter" segment is configured to convert an electrical signal into a transmitted acoustic signal (e.g., toward an obstacle), and the "receiver" segment is configured to convert a received acoustic signal (e.g., reflected from an obstacle) into an electrical signal.

[0043] However, the embodiments are not limited to this possible arrangement and can be advantageously applied to arrangements that include both a "transmitter" segment and a "receiver" segment, referred to as "transceiver" for the sake of brevity.

[0044] Similarly, while the exemplary description provided below refers to an ultrasonic transducer for simplicity and ease of understanding, in general, one or more embodiments can be applied to electroacoustic transducers capable of acting as transducers between the electrical and acoustic domains. In this regard, although PMUT is referred to throughout for simplicity and ease of understanding, the embodiments can be advantageously applied to electroacoustic transducers other than PMUTs, where problems such as those discussed above may arise.

[0045] Finally, while one or more embodiments may be considered to use different transducers for transmission and reception, some embodiments may be considered to be configured as a single transducer that serves as both a transmitter and a receiver.

[0046] like Figure 1 As illustrated, the PMUT transducer device 10 includes a MEMS-based piezoelectric layer 12 sandwiched between electrodes or terminals 14a and 14b and suspended on a (silicon) substrate 16, thereby forming a film stack 14a, 12, 14b, 16.

[0047] As illustrated in this article, device 10 can be used as both a transmitter and a receiver.

[0048] When operating as a transmitter, a voltage generator configured to generate an AC voltage is connected to contacts 14a, 14b to generate a corresponding electric field in the piezoelectric layer 12, thereby causing its deformation (due to the inverse piezoelectric effect), and the deformation caused by the same reason as the geometry of the device 10 also causes the membrane to deflect, thereby generating a corresponding pressure wave emission in the surrounding medium.

[0049] When operating as a receiver, the incoming pressure wave causes the piezoelectric layer 12 to deflect, thereby causing charge polarization at the transducer contacts 12a, 12b due to the (direct) piezoelectric effect; this polarization can be detected by an amplifier (e.g., a transimpedance amplifier) ​​connected to the transducer terminals 14a, 14b.

[0050] Figure 1The illustration shows the possible opposite deflection or deformation of layer 12 due to the application of appropriate AC voltage at its contacts 14a, 14b.

[0051] As discussed, the number of membranes used can range from one (a stack of membranes used for transmission and then switched to the receiver) to more than one during transmission and from one to more than one during reception.

[0052] For example, when performing 2D or 3D echolocation, using multiple membranes can be advantageous because it increases sensitivity during transmission or reception. Sensitivity can be defined as the maximum (amplitude) value of the correlated frequency response or transfer function.

[0053] like Figure 1 The arrangement illustrated is otherwise conventional in the art, which makes it unnecessary to provide a more detailed description herein.

[0054] As discussed above, the obstacle detection / ranging transducer arrangement considered in this paper is an example of a variety of possible applications (volume measurement, gesture recognition, flow metering, to name a few), including applications that consider only the "transmitter" segment or only the "receiver" segment.

[0055] As discussed, when an ultrasonic transducer such as the PMUT 10 is used in such an application, the bandwidths of the transmitter segment and / or receiver segment do not overlap, or only partially overlap, so that the acquired signal may contain little or no information about the reflected sound.

[0056] like Figure 2 exemplified, Figure 1 The illustrated piezoelectric ultrasonic transducer device 10 can be modeled using a Butterworth-van Dyke (BVD) model. As those skilled in the art will know, a BVD model is an electrical equivalent network of lumped elements that models the behavior of the device 10 in at least one of the mechanical, acoustic, and electrical domains.

[0057] For background purposes only, the Butterworth-van Dyke model (also known as the "Mason" model or "KLM" model) is the electrical equivalent circuit of an electroacoustic transducer, comprising an electrical domain coupled to the mechanical domain (theoretically having multiple normal modes) via electromechanical coupling. The mechanical domain is then coupled to the acoustic domain via mechatronic coupling. The Butterworth-van Dyke / Mason / KLM is known to those skilled in the art, and therefore a more detailed description is unnecessary herein.

[0058] As an electrical equivalent circuit, the electrical domain can be represented using an equivalent network, such as that seen at electrical contacts or terminals 14a and 14b, for example. Figure 2As shown, for example, when performing impedance measurements, the equivalent network includes a capacitor with a value of C0 connected in parallel with an RLC branch, which includes a resistor with a value of R, an inductor with a value of L, and a capacitor with a value of C connected in series.

[0059] Figure 3A and Figure 3B Is this for reference? Figure 2 The magnitude of the impedance Z visible at the input port of the equivalent circuit under discussion (dBOhm- Figure 3A (vertical coordinate) and phase (degrees - Figure 3B (vertical axis) and frequency (kHz- Figure 3A and Figure 3B Example diagram (the horizontal axis in the diagram).

[0060] The following relationships may apply Figure 2 The illustrated equivalent circuit:

[0061] f0=(1 / 2π)(L / [C0C / (C0+C)]) 1 / 2

[0062] τ = 2(L / R)

[0063] Here, f0 and τ indicate the resonant frequency and decay time, respectively. These can be obtained from the measurement / detection of the decaying signal, as discussed below.

[0064] Given two equations and four unknowns (i.e., BVD model parameters L, R, C, C0), such a system does not allow for unambiguous solutions. However, in the current context (e.g., PMUT), it is possible to make a (wise) assumption that C0 is much larger than C (so that a constant value can be used for C0). The value of the resistor R can be determined based on the amplitude of the oscillating signal discussed below, so that the system can be solved.

[0065] Considering the impedance Z at the input port of the equivalent circuit, we can address the following respectively: Figure 4 and Figure 5 The transmitter transducer (electric to acoustic) and receiver transducer (acoustic to electrical) shown are provided in a simplified BVD model, wherein the parts or elements already discussed in conjunction with the previous figures are indicated by the same reference numerals.

[0066] exist Figure 4 In the transmitter model, ES represents the (electrical) excitation signal, which is coupled at its node (e.g., Figure 1 A voltage generator 50 at electrodes 14a and 14b of device 10 is applied to the transmitter transducer device. The generator 50 generates a current A in the RLC branch of the circuit, which is proportional to the ultrasonic pressure level emitted by transducer 10.

[0067] like Figure 4 The illustrated circuit has a response or transfer function H T (s), the response or transfer function H T (s) can be represented as:

[0068]

[0069] exist Figure 5 In the receiver model, PV represents the indication of the incident (and) (ultrasonic) pressure level (e.g., in...). Figure 1 The voltage (proportional) sensed at the membrane layer 12 in the device 10, and SM indicates that it can be coupled at the node of the device 10 (e.g., at the point where the membrane layer 12 is located). Figure 1 The measured (current) signal is sensed by the transimpedance amplifier 60 at electrodes 14a and 14b of device 10.

[0070] Due to reciprocity, such as Figure 5 The response or transfer function H of the illustrated circuit R (s) equals the transmitter mode response or transfer function H R (s), therefore it can be represented as:

[0071]

[0072] For simplicity, since the response / transfer functions of the receiver / transmitter arrangement are equal, a single common transfer function G(s) will be referred to in the following discussion.

[0073] It should be noted that widening the bandwidth BW of the transfer function G(s) of device 10 without reducing sensitivity can improve the latter's performance.

[0074] like Figure 6 As illustrated, a way to broaden the bandwidth of device 10 may include coupling a (passive) load circuit block 70, which is inserted between generator 50 (or amplifier 60) and input ports (e.g., modeled by an equivalent network), to device 10.

[0075] For example, load circuit block 70 may include a load resistor R arranged in series between a node of generator 50 (or amplifier 60) and node 14a of the BVD model equivalent circuit. L and load inductor L L .

[0076] like Figure 6 The common transfer function G(s) of the illustrated arrangement can be expressed as:

[0077]

[0078] in

[0079] is the impedance of capacitor C0,

[0080] Z RLC (s) is the impedance of the RLC branch, and

[0081] Z TOT (s) is the impedance seen from the input port at ES.

[0082] Figure 7A and Figure 7B respectively show Figure 4 、 Figure 5 's arrangement (solid line, marked as RLC) and the absolute value |G(s)| and phase <G(s) of the transfer function G(s) of the arrangement (dashed line, marked as RLC+RL) including the load in comparison with frequency. Figure 6 of the arrangement including the load

[0083] At Figure 7A 、 Figure 7B 's exemplary case, a resonant frequency of 100 kHz and a fractional bandwidth of 1% can be considered for deriving the parameters of the equivalent circuit based on the BVD model.

[0084] As illustrated herein, the parameters R, L, C, C0, and the resonant frequency f0 and decay time τ of the BVD model circuit can be measured and calibrated using the method discussed in US 2020 / 0292684 A1.

[0085] Figure 7A and Figure 7B illustrate the transfer function of the circuit as exemplified in the case where the load block 70 includes a resistor having a (first) resistance value R L and an inductor L having an inductance value L L (e.g., about millihenry) and the transfer function of the circuit as exemplified in Figure 6 and as exemplified in Figure 4 (or Figure 5 ).

[0086] As Figure 7A and Figure 7B exemplify:

[0087] Figure 7A and Figure 7B 's circular marks are at the first peak frequency f0 of the device 10;

[0088] Figure 7A and Figure 7B 's dot marks are at the second peak frequency f0' of the device 10 coupled to the load 70;

[0089] The diamond-shaped markers indicate the first (-3dB) cutoff frequencies for f1 and f2; and

[0090] The square markers indicate the second (-3dB) cutoff frequencies f1' and f2'.

[0091] Figure 7A and Figure 7B This is an example of the possibility of widening the -3dB bandwidth (which refers to the maximum absolute value of the transfer function) from the first value BW = 1% (RLC) to the second value BW' = 6.3% (RLC + RL) as a result of coupling the load block 70 to the device 10.

[0092] This result can also be understood through a simple visual comparison between the magnitude values ​​of the transfer function G(s) of the equivalent circuits of RLC and RLC+RL.

[0093] While examples of advantageous alternatives exist, the numerical values ​​mentioned above should not be construed as, or even indirectly, a limitation on the embodiments.

[0094] Figure 7A It was also demonstrated that, due to the load 70 coupled to device 10, the sensitivity could potentially increase, for example, by +10 dB, as the peak value (absolute value) of the transfer function G(s) increases.

[0095] In one or more embodiments, the load block 70 can be configured to (ideally) maximize the bandwidth of the transfer function G(s) while promoting sensitivity compliance with certain specifications.

[0096] This may involve based on Figure 2 The parameters R, L, C, C0 of the load block 70 are determined as a function of the values ​​of the parameters R, L, C, C0 of the equivalent network circuit in the BVD model (e.g., R). L L L The choice of value for ).

[0097] like Figure 6 As illustrated, the external load 70 may include components configured (for a resistor RL and / or for an inductor L) L Adjustable (e.g., programmable) loads whose values ​​are adjusted in a timely manner.

[0098] This can facilitate maintaining a wide bandwidth (BW) over extended periods, compensating for potential changes in PMUT parameters over time (e.g., due to aging, drift, hysteresis caused by voltage bias changes, etc.).

[0099] Advantageously, the load inductor L LThis can be a “synthetic” inductor, for example, a circuit configured to simulate the behavior of an inductor, as illustrated in “Analytical Study of Inductor Simulation Circuits” by U. Kumar et al. in Active and Passive Elec. Comp., 1999. Using such a synthetic inductor can facilitate obtaining inductance values ​​in the millihenry range and promote circuit integration.

[0100] In one or more embodiments, the load parameter R L L L Choosing the theoretically "optimal" value can be cumbersome. The external load 70 adds two new poles to the transfer function G(s); ideally, these poles are complex conjugates of each other and located at frequencies close to the frequency of the RLC branch of device 10.

[0101] In one or more embodiments, the following scenarios may exist:

[0102] a) The capacitance values ​​of C0 and C in the BVD model circuit satisfy the following expression:

[0103]

[0104] b) The transducer may have a very narrow bandwidth (e.g., Q factor ≈ 100).

[0105] In this exemplary scenario, an approximate value for load 70, which includes a resistor R, can be calculated. L0 and inductor L L0 The resistor R is arranged in series. L0 and inductor L L0 The values ​​match those of the RLC resonant circuit in the BVD model, and these can be expressed as:

[0106]

[0107]

[0108] k can be in the range of 5 to 10 in order to further increase the bandwidth of the transducer.

[0109] In one or more embodiments, to account for cases where the Q factor may have a low value, for example, Q factor ≈ 10, the calculation of the value of the parameter of the external load 70 can be performed iteratively.

[0110] For example, due to the approximate optimal value R L0 L L0 The calculation is based on the BVD model parameters, so the load parameter R can be further adjusted starting from the calculated value. LL L To compensate for other elements in a particular implementation, such as those modeled as Figure 4 The non-zero output impedance of the voltage generator in box 50.

[0111] For example, to adapt the model to include any Q-factor value, the parameters R of the load block 70 can be determined iteratively. L L L The value of .

[0112] like Figure 8 As illustrated, in order to demonstrate an exemplary way of iteratively determining values, since these parameters can be determined independently of each other, the following uses different indices, denoted as N, M, P, and their combinations, to represent a certain number of sample values ​​for a parameter.

[0113] For example, possible processes for determining these values ​​may include the following, such as Figure 8 Example:

[0114] Determine (box 100) the BVD model equivalent network circuit of device 10 and (in a manner known to those skilled in the art) determine the initial values ​​of its circuit parameters R, L, C, C0 and resonant frequency f0;

[0115] The first external load parameter L is generated by sampling values ​​within a corresponding (e.g., different) range using a certain (e.g., different) sampling step size (box 102). L1 ... L LN and / or the second external load parameter R L1 ... R LM The set of values, where the range center value is equal to the calculated approximate "optimal" value R of the corresponding first and / or second parameters. L0 L L0 At least one value in;

[0116] The set of frequency values ​​f1, ..., f2 is generated by sampling values ​​within a frequency range centered on the resonant frequency f0 using a certain sampling step size (box 104). P ;

[0117] By using the first external load parameter L L Second external load parameter R L The obtained first and second value sets are calculated (box 106) respectively in the frequency value sets f1, ..., f P The set of transfer functions (power spectrum) at point G1(s), ..., G NM (s);

[0118] The set of (squared) transfer functions G1(s), ..., G1(s) calculated in (box 108)NM The bandwidth set BW1, ..., BW of the corresponding (squared) transfer function in (s) NM And the sensitivity set S1, ..., S NM ;

[0119] Compare the calculated bandwidth with the sensitivity (box 110), in the squared transfer function G1(s), ..., G NM Selecting the "best" squared transfer function G from the set of (s) i (s), the “optimal” squared transfer function has a relatively maximum bandwidth and sensitivity above or below a certain threshold; and

[0120] External load parameter R L L L The value is set (box 112) to be equal to the set of transfer functions G1(s), ..., G used to calculate the squares. NM The external load parameter L of the selected “optimal” squared transfer function in (s) L1 ... L LN and R L1 ... R LM The values ​​of the external load parameters in the value set.

[0121] In one or more embodiments, the threshold for the sensitivity value can be customized according to the application used for the PMUT device 10.

[0122] This approach may overlook some non-ideals or other effects related to the physical PMUT layout, and can be further adjusted for external load R. L L L The values ​​found are used to compensate for other elements of a particular implementation, such as, for example, being modeled as Figure 4 The non-zero output impedance of the voltage generator in box 50.

[0123] Alternatively, the load parameter R of the external load 70 L L L Experimental methods can be used to determine this, as discussed below.

[0124] In order to achieve this, such as Figure 9 Example:

[0125] PMUT 10 can be coupled to a measurement unit MU, which is configured to measure its actual resonant frequency f6 and damping parameter τ. i For example, the measurement can be performed in real time;

[0126] The load 70 may include components that are adjustable in real time; such as, as discussed, an inductor L. L and resistor RL Both can be programmable in real time; and

[0127] The control unit CU, coupled to the voltage generator 50, the load 70, and the measurement unit MU, can (in a manner known to those skilled in the art) be configured to receive the measured resonant frequency f6 from the measurement unit MU, control the voltage generator 50, and adjust the load parameter R as needed. L L L Things have changed.

[0128] Used to determine such Figure 9 The load parameter R of the external load 70 in the illustrated arrangement L L L Experimental methods may include:

[0129] (Again, in a manner known to those skilled in the art) Measure the resonant frequency f6 of PMUT device 10;

[0130] By using a certain (e.g., different) sampling step size pair with the calculated approximate optimal value R L0 L L0 The corresponding value is sampled from a corresponding (e.g., different) range centered on the value to provide the first external load parameter L. L1 ... L LN Second external load parameter R L1 ... R LM The set of values;

[0131] For example, the resistor R of load 70 is controlled by the control unit CU. L and inductor L L Iterative adjustment equals the external load parameter L L1 Iterative adjustment L LN and R L1 Iterative adjustment of R LM The first parameter L in the provided set of values L The i-th value and the second parameter R L The i-th value;

[0132] An excitation signal ES is applied to device 10, for example, to a generator 50 whose frequency is controlled to be equal to the measured resonant frequency f6;

[0133] For example, the i-th oscillation signal RDi, which indicates the oscillation behavior of the transducer 10 after the excitation signal ES ends, is acquired via the measurement unit MU;

[0134] The acquired ring-down signal RDi is processed to obtain the following results:

[0135] a) The i-th decay time constant τ of the bandwidth of device 10 i ;as well as

[0136] b) The amplitude RDA (initial, peak-to-peak) of the sensitivity of the transfer function G(s) of the indicating device 10 for the fading signal, such as Figure 10A and Figure 10B exemplified;

[0137] Collect each i-th decay time constant τ i The amplitude of the i-th oscillation signal RDi;

[0138] For example, via control unit 10, a comparison is performed between the collected signals indicating bandwidth and sensitivity, and based on the comparison, a comparison is made with the provided external load parameter L. L1 ... L LN and R L1 ... R LM Select the load parameter L from the set of values ​​that indicates the relative maximum bandwidth and sensitivity above or below a certain threshold. L *、R L *The "optimal" value; and

[0139] For example, via control unit 10, the load block 70 (e.g., load resistor and inductor R) is... L L L Set or configure it to be equal to the load parameter L L1 ... L LN and R L1 ... R LM Select the external load parameter R from the set of values. L *、L L The "optimal" value for *.

[0140] Figure 10A and Figure 10B Here are examples of the sensed ringing signals RDi and RD*, where

[0141] Figure 10A It is the detected ringing signal RDi, for example, the ringing signal RDi where no external load block is coupled to device 10; and

[0142] Figure 10B The (i-th) oscillation signal is detected by the load block 70 coupled to device 10, such as... Figure 6 As illustrated, for example, by using the “optimal” load parameter R selected according to the discussion above. L *、L L *The oscillation signal RD detected by the configured load block 70*.

[0143] Figure 11 , Figure 12 and Figure 13 This is an example of a possible alternative architecture for load block 70.

[0144] Figures 11 to 13 Here are examples of possible alternative implementations of load 70, and the standards discussed above can be adapted to these implementations with necessary modifications:

[0145] like Figure 11 As illustrated, the load 70 includes a first input node and a second input node configured to receive an input signal ES therebetween; and a first output node and a second output node, wherein the inductor L L The resistor R is positioned between the first input node and the first output node. P It is positioned between the two output nodes, that is, in parallel with capacitor C0, which can essentially be considered as an L capacitor. L (Upper branch road) and R P The voltage divider arrangement (for the lower branch) wherein the first output node is coupled to the split point of the voltage divider; and

[0146] like Figure 12 and Figure 13 The other resistor R illustrated S With inductor L L Series arrangement (e.g.) Figure 12 (As illustrated) or located in the inductor L L Coupled to resistor R P The node and the first output node (e.g.) Figure 13 exemplified).

[0147] If the approximation C0 >> C applies and satisfies the following equation, then as Figure 11 The illustrated arrangement may be suitable for use and may correspond to the arrangement in Figure 7:

[0148]

[0149] When the following conditions are met, such as Figure 12 and Figure 13 The illustrated arrangement may be suitable for use and may correspond to the arrangement in Figure 7:

[0150] a) The approximation applicable to C0 >> C;

[0151] b) Resistor R S and R P The following conditions must be met:

[0152]

[0153] c) such as Figure 12 and Figure 13The resistor R shown in the example S R P Configured to make resistor R S This can be expressed as the total load resistance R. L functions, for example, and

[0154] d) Resistor R P It can be expressed as a function of the total load resistance and the parameters of the BVD model, for example,

[0155] It should be pointed out that, in addition, in cases such as Figures 11 to 13 In the illustrated arrangement, based on the foregoing discussion of Figure 7, the load parameter R can be determined. L L L The "optimal" values ​​are then used to calculate the values ​​of the corresponding layout parameters (e.g., Rs, Rp). For the sake of brevity, since the aforementioned (specifically, regarding...) Figure 8 and Figure 9 The content discussed has been modified as necessary, so the corresponding description of the method operation will not be repeated.

[0156] As shown in Figure 7, Figures 11 to 13 The illustrated arrangement can be suitable for, for example, an acoustic position sensor module 1000, which may be configured to be mounted on a motor vehicle such as a motor vehicle. Figure 14 As illustrated, this could include an analog front-end 1002 coupled to one or more transducers 10 (PMUT is an example of such a transducer); and a software component 1004 that operates on the processing circuitry of a microcontroller unit (MCU) with peripheral devices having processing units in a hardware architecture that may at least partially include 1002.

[0157] It should be understood otherwise that the microcontroller is merely one example of a processing unit among a plurality of processing units that may be used in the embodiments.

[0158] In one or more embodiments, the analog front end 1002 and the processing unit 1004 may be powered as needed via the power management circuit 1006.

[0159] As discussed earlier, Figure 14 This is an example of a circuit / system architecture configured to host (e.g., at 1004) a software program capable of performing adjustments (online, real-time) such as R to a load block 70 coupled to device 10. L and L LLoad parameters such as those used to increase its bandwidth (BW) and, taking into account potential drawbacks related to the narrow available bandwidth and / or possible limitations associated with manufacturing expansion / time-varying transducer parameters, may increase its sensitivity.

[0160] As illustrated in this article, one approach includes:

[0161] Obtain (e.g., 100) the resonant frequency (e.g., f0) and at least one ringing parameter (e.g., τ) of an electroacoustic transducer (e.g., 10) having sensitivity and frequency bandwidth. i At least one of (RDA);

[0162] The model parameter set (e.g., R, L, C, C0) of the Butterworth-Van Dyke (BVD) model of the electroacoustic transducer is calculated as a function of the resonant frequency and at least one of the at least one damping parameters. The BVD model includes an equivalent circuit network having a constant capacitance (e.g., C0) coupled to an RLC branch (e.g., R, L, C).

[0163] An adjustable load circuit (e.g., 70) coupled to an electroacoustic transducer, the adjustable load circuit having an adjustable set of load parameters (e.g., L) L R L The adjustable load parameter set includes at least one resistance parameter (R). L ) and an inductance parameter (e.g., L) L The adjustable load circuit is coupled to the electroacoustic transducer at the input port of the equivalent circuit network of the BVD model of the electroacoustic transducer; and

[0164] The adjustable load parameter set is adjusted according to the calculated model parameter set of the BVD model of the electroacoustic transducer to increase at least one of the bandwidth and the sensitivity of the electroacoustic transducer as a result of the adjustment.

[0165] As illustrated herein, the method also includes:

[0166] Generates (e.g., 102) a set of load candidate values ​​(e.g., L) of adjustable load parameters. L1 ... L LN ;R L1 ... R LM The load candidate value set includes at least one initial configuration value set (e.g., R). L0 L L0 );

[0167] This generates (e.g., 104) a set of frequency values ​​distributed across a frequency range (e.g., f1, ..., f...). PThe set of frequency values ​​includes frequency values ​​equal to the resonant frequency;

[0168] Based on the set of frequency values ​​and the set of load candidate values, obtain (e.g., 106) at least one set of signals indicating the bandwidth and sensitivity of the electroacoustic transducer;

[0169] Perform a comparison (e.g., 110) between a sensitivity threshold and the signals in at least one obtained signal set, and select a subset of the signals in the at least one signal set as the result of the comparison;

[0170] Select (e.g., 112) from the set of load candidates that maximize bandwidth (e.g., L). L *、R L *), where the bandwidth-maximizing load candidate is the set of load candidate values ​​in the load candidate set that corresponds to the bandwidth-maximizing signal (e.g., G*(s)), which has a relatively maximum bandwidth in the selected subset of the signals indicating the bandwidth and sensitivity of the electroacoustic transducer; and

[0171] The adjustable load parameter set of the adjustable load circuit network is adjusted to be equal to the bandwidth-maximizing load candidate value set.

[0172] As illustrated herein, obtaining (e.g., 106) at least one set of signals indicating the bandwidth and sensitivity of an electroacoustic transducer includes: calculating a set of frequency responses of the electroacoustic transducer based on the set of frequency values ​​and the set of load candidate values.

[0173] As illustrated in this article, the method includes:

[0174] Generate (e.g., 102) a set of adjustable load parameters (e.g., L) L R L A sequence of load candidate values, the set of load candidate values ​​including at least one set of initial configuration values;

[0175] Perform iterative acquisition of a oscillating signal sequence that indicates the bandwidth and sensitivity of the electroacoustic transducer coupled to the load circuit network;

[0176] Perform (e.g., 110) a comparison of the sensitivity threshold with the initial amplitude value of the acquired ring-down signal sequence, and select a subset of the ring-down signal sequence (e.g., RD*) as the result of the comparison;

[0177] Select a set of load candidates that maximizes bandwidth from the set of load candidates, wherein the set of load candidates that maximizes bandwidth is the set of load candidates in the set of load candidates that corresponds to the set of load candidates that maximizes bandwidth decay signal, which has a relatively maximum bandwidth (e.g., at least one damping parameter τ*) in the decay signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer; and

[0178] The adjustable load parameter set is adjusted to be equal to the bandwidth-maximizing load candidate value set.

[0179] As illustrated herein, for each candidate value in the sequence of load candidate values, the iterative acquisition includes a sequence of operations, which includes:

[0180] i) Adjust the set of adjustable load parameters of the adjustable load circuit network to be equal to the i-th load candidate value in the set of load candidate values;

[0181] ii) Applying an excitation signal (e.g., 50, ES) to the transducer during the excitation interval; and

[0182] iii) Acquire (e.g., 60, PV) a oscillation signal at the transducer indicating the oscillation behavior of the transducer after the excitation interval ends.

[0183] As illustrated herein, the set of initial configuration values ​​for the load circuit system includes at least one of the following:

[0184] i) The initial inductor configuration value L0 is represented as:

[0185]

[0186] ii) Initial resistor configuration value R L0 , is represented as:

[0187]

[0188] in

[0189] C, C0, R, L, and f0 are the parameters of the calculated BVD model, and

[0190] k is a numerical value, preferably in the range of 5 to 10.

[0191] As illustrated in this article, a circuit includes:

[0192] At least one electroacoustic transducer (e.g., 10) has sensitivity and frequency bandwidth;

[0193] Adjustable load circuit (e.g., 70), having an adjustable load parameter set (e.g., L) L RL The adjustable load parameter set includes resistance parameters (e.g., R). L ) and inductance parameters (e.g., L) L At least one of the following; and

[0194] A processing circuit system (e.g., 50, 60, MU, CU) is coupled to the at least one electroacoustic transducer and the adjustable load circuit system, the processing circuit system being configured to perform the following actions:

[0195] Obtain (e.g., 100) the resonant frequency (e.g., f0) and at least one ringing parameter (e.g., τ) of the electroacoustic transducer. i At least one of (RDA);

[0196] The set of model parameters (e.g., R, L, C, C0) for calculating the Butterworth-Van Dyke (BVD) model of the electroacoustic transducer; and

[0197] The adjustable load parameter set is adjusted according to the calculated set of model parameters of the BVD model as illustrated in the method herein.

[0198] As illustrated herein, the electroacoustic transducer is an ultrasonic electroacoustic transducer, preferably a piezoelectric micromechanical ultrasonic transducer (PMUT).

[0199] As illustrated herein, the adjustable load circuit includes one of the following:

[0200] Resistors (e.g., R) L ) and inductors (e.g., L L ) series connection; and

[0201] Voltage divider, including inductors (e.g., L...). L and at least one resistor (e.g., R) P R S ).

[0202] As illustrated herein, a device includes circuitry as illustrated herein, and the device is selected from the following:

[0203] Obstacle detection equipment, preferably vehicle-mounted (e.g., V);

[0204] Echolocation equipment; and

[0205] Sound wave time-of-flight measurement equipment.

[0206] Without departing from the scope of protection, details and embodiments may be varied, even significantly, relative to what has been described by example only, without violating the fundamental principles.

[0207] Other embodiments can be provided by combining the various embodiments described above. These and other changes can be made to the embodiments according to the specific implementation described above. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be construed as including all possible embodiments and their equivalents within the full scope of such claims. Therefore, the claims are not limited to this disclosure.

Claims

1. A method for operating equipment, comprising: Obtain at least one resonant frequency from a plurality of resonant frequencies and at least one ring-down parameter from a plurality of ring-down parameters of an electroacoustic transducer having sensitivity and frequency bandwidth. Based on the at least one resonant frequency and the at least one ring-down parameter, calculate the set of model parameters for the Butterworth-Van Dyke (BVD) model of the electroacoustic transducer, wherein the BVD model includes an equivalent circuit network having a constant capacitance coupled to an RLC branch. An adjustable load circuit is coupled to the electroacoustic transducer, the adjustable load circuit having an adjustable load parameter set including at least one resistance parameter and one inductance parameter, wherein the adjustable load circuit is coupled to the electroacoustic transducer at the input port of the equivalent circuit network of the BVD model of the electroacoustic transducer. The adjustable load parameter set is adjusted based on the calculated set of model parameters of the BVD model of the electroacoustic transducer to increase at least one of the bandwidth and the sensitivity of the electroacoustic transducer as a result of the adjustment; Generate a set of load candidate values ​​for the adjustable load parameter set, the set of load candidate values ​​including at least one set of initial configuration values; as well as Perform iterative acquisition of a cascading signal sequence, which indicates the bandwidth and sensitivity of the electroacoustic transducer coupled to the adjustable load circuit.

2. The method according to claim 1, comprising: Generate a set of load candidate values ​​for the set of adjustable load parameters, the set of load candidate values ​​including at least one set of initial configuration values; Generate a set of frequency values ​​distributed across a frequency range, the set of frequency values ​​including frequency values ​​equal to the resonant frequency; Based on the set of frequency values ​​and the set of load candidate values, at least one set of signals indicating the bandwidth and sensitivity of the electroacoustic transducer is obtained; Perform a comparison between a sensitivity threshold and the signals in the at least one obtained signal set, and select a subset of the signals in the at least one signal set as the result of the comparison; A set of load candidate values ​​with maximum bandwidth is selected from the set of load candidate values, wherein the set of load candidate values ​​with maximum bandwidth is the set of load candidate values ​​in the set of load candidate values ​​corresponding to the bandwidth-maximizing signal, which has a relatively maximum bandwidth among the selected subset of signals indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set of the adjustable load circuit is adjusted to be equal to the bandwidth-maximizing load candidate value set.

3. The method of claim 2, wherein obtaining at least one set of signals indicative of the bandwidth and sensitivity of the electroacoustic transducer comprises: The frequency response set of the electroacoustic transducer is calculated based on the set of frequency values ​​and the set of candidate load values.

4. The method according to claim 2, comprising: Generate a set of load candidate values ​​for the set of adjustable load parameters, the set of load candidate values ​​including at least one set of initial configuration values; Perform iterative acquisition of the decaying signal sequence, which indicates the bandwidth and sensitivity of the electroacoustic transducer coupled to the adjustable load circuit; A comparison is made between a sensitivity threshold and the initial amplitude value of the acquired ring-down signal sequence, and a subset of the ring-down signal sequence is selected as the result of the comparison. Select a set of load candidate values ​​that maximizes bandwidth from the set of load candidate values, wherein the set of load candidate values ​​that maximizes bandwidth is the set of load candidate values ​​in the set of load candidate values ​​that corresponds to the set of load candidate values ​​that maximizes bandwidth decay signal, which has a relatively maximum bandwidth in the decay signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set is adjusted to be equal to the bandwidth-maximizing load candidate value set.

5. The method according to claim 1, comprising: A comparison is made between a sensitivity threshold and the initial amplitude value of the acquired ring-down signal sequence, and a subset of the ring-down signal sequence is selected as the result of the comparison. Select a set of load candidate values ​​that maximizes bandwidth from the set of load candidate values, wherein the set of load candidate values ​​that maximizes bandwidth is the set of load candidate values ​​in the set of load candidate values ​​that corresponds to the set of load candidate values ​​that maximizes bandwidth decay signal, which has a relatively maximum bandwidth in the decay signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set is adjusted to be equal to the bandwidth-maximizing load candidate value set.

6. The method of claim 5, wherein for each candidate value in the set of load candidate values, the iterative acquisition includes an operation sequence, the operation sequence comprising: The adjustable load parameter set of the adjustable load circuit is adjusted to be equal to the load candidate value in the load candidate value set; An excitation signal is applied to the transducer during the excitation interval; as well as A oscillation signal is acquired at the transducer, the oscillation signal indicating the oscillation behavior of the transducer after the excitation interval ends.

7. The method of claim 1, wherein the set of initial configuration values ​​for the adjustable load circuit includes at least one of the following: The initial inductor configuration value L0 is represented as: Or the initial resistor configuration value R L0 , is represented as: in C, C0, R, L, and f0 are the parameters of the calculated BVD model, and k is a numerical value.

8. The method of claim 7, wherein k is a value in the range of 5 to 10.

9. An electronic circuit, comprising: At least one electroacoustic transducer with sensitivity and frequency bandwidth; An adjustable load circuit having an adjustable load parameter set, the adjustable load parameter set including at least one resistance parameter and one inductance parameter; and A processing circuit system, coupled to the at least one electroacoustic transducer and the adjustable load circuit, the adjustable load circuit having an adjustable load parameter set including at least one resistance parameter and one inductance parameter, the processing circuit system being configured to: Obtain at least one resonant frequency from a plurality of resonant frequencies of the electroacoustic transducer and at least one ring-down parameter from a plurality of ring-down parameters; Based on the at least one resonant frequency and the at least one ring-down parameter, calculate the set of model parameters for the Butterworth-Van Dyke (BVD) model of the electroacoustic transducer, the BVD model including an equivalent circuit network having a constant capacitance coupled to an RLC branch, wherein the adjustable load circuit is coupled to the electroacoustic transducer at the input port of the equivalent circuit network of the BVD model of the electroacoustic transducer; as well as The adjustable load parameter set is adjusted according to the calculated model parameter set of the BVD model of the electroacoustic transducer to increase at least one of the bandwidth and the sensitivity of the electroacoustic transducer; Generate a set of load candidate values ​​for the adjustable load parameter set, the set of load candidate values ​​including at least one set of initial configuration values; Generate a set of frequency values ​​distributed across a frequency range, the set of frequency values ​​including frequency values ​​equal to the resonant frequency; Based on the set of frequency values ​​and the set of load candidate values, at least one set of signals indicating the bandwidth and sensitivity of the electroacoustic transducer is obtained; Perform a comparison between a sensitivity threshold and the signals in the at least one obtained signal set, and select a subset of the signals in the at least one signal set as the result of the comparison.

10. The electronic circuit of claim 9, wherein the processing circuit system is configured to: A set of load candidate values ​​with maximum bandwidth is selected from the set of load candidate values, wherein the set of load candidate values ​​with maximum bandwidth is the set of load candidate values ​​in the set of load candidate values ​​corresponding to the bandwidth-maximizing signal, which has a relatively maximum bandwidth among the selected subset of signals indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set of the adjustable load circuit is adjusted to be equal to the bandwidth-maximizing load candidate value set.

11. The electronic circuit of claim 10, wherein the processing circuit system is configured to obtain at least one set of signals indicative of the bandwidth and sensitivity of the electroacoustic transducer by calculating a set of frequency responses of the electroacoustic transducer based on the set of frequency values ​​and the set of load candidate values.

12. The electronic circuit of claim 10, wherein the processing circuit system is configured to: Generate a set of load candidate values ​​for the set of adjustable load parameters, the set of load candidate values ​​including at least one set of initial configuration values; Perform iterative acquisition of a cascading signal sequence, the cascading signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer coupled to the adjustable load circuit; A comparison is made between a sensitivity threshold and the initial amplitude value of the acquired ring-down signal sequence, and a subset of the ring-down signal sequence is selected as the result of the comparison. Select a set of load candidate values ​​that maximizes bandwidth from the set of load candidate values, wherein the set of load candidate values ​​that maximizes bandwidth is the set of load candidate values ​​in the set of load candidate values ​​that corresponds to the set of load candidate values ​​that maximizes bandwidth decay signal, which has a relatively maximum bandwidth in the decay signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set is adjusted to be equal to the bandwidth-maximizing load candidate value set.

13. The electronic circuit of claim 9, wherein the processing circuit system is configured as follows: Perform iterative acquisition of a cascading signal sequence, the cascading signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer coupled to the adjustable load circuit; A comparison is made between a sensitivity threshold and the initial amplitude value of the acquired ring-down signal sequence, and a subset of the ring-down signal sequence is selected as the result of the comparison. Select a set of load candidate values ​​that maximizes bandwidth from the set of load candidate values, wherein the set of load candidate values ​​that maximizes bandwidth is the set of load candidate values ​​in the set of load candidate values ​​that corresponds to the set of load candidate values ​​that maximizes bandwidth decay signal, which has a relatively maximum bandwidth in the decay signal sequence indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set is adjusted to be equal to the bandwidth-maximizing load candidate value set.

14. The electronic circuit of claim 13, wherein for each candidate value in the set of load candidate values, the iterative acquisition includes an operation sequence comprising: The adjustable load parameter set of the adjustable load circuit is adjusted to be equal to the load candidate value in the load candidate value set; An excitation signal is applied to the transducer during the excitation interval; as well as A oscillation signal is acquired at the transducer, the oscillation signal indicating the oscillation behavior of the transducer after the excitation interval ends.

15. The electronic circuit according to claim 9, wherein the electroacoustic transducer comprises an ultrasonic electroacoustic transducer.

16. The electronic circuit according to claim 15, wherein the electroacoustic transducer comprises a piezoelectric micromechanical ultrasonic transducer.

17. The electronic circuit of claim 9, wherein the adjustable load circuit comprises one of the following: A resistor and an inductor connected in series; or A voltage divider includes an inductor and at least one resistor.

18. An electronic device comprising: The circuit includes: At least one electroacoustic transducer with sensitivity and frequency bandwidth; An adjustable load circuit having an adjustable load parameter set, the adjustable load parameter set including at least one resistance parameter and one inductance parameter; and A processing circuit system, coupled to the at least one electroacoustic transducer and the adjustable load circuit, the adjustable load circuit having an adjustable load parameter set including at least one resistance parameter and one inductance parameter, the processing circuit system being configured to: Obtain at least one resonant frequency from a plurality of resonant frequencies of the electroacoustic transducer and at least one ring-down parameter from a plurality of ring-down parameters; Based on the at least one resonant frequency and the at least one ring-down parameter, calculate the set of model parameters for the Butterworth-Van Dyke (BVD) model of the electroacoustic transducer, the BVD model including an equivalent circuit network having a constant capacitance coupled to an RLC branch, wherein the adjustable load circuit is coupled to the electroacoustic transducer at the input port of the equivalent circuit network of the BVD model of the electroacoustic transducer; and The adjustable load parameter set is adjusted according to the calculated model parameter set of the BVD model of the electroacoustic transducer to increase at least one of the bandwidth and the sensitivity of the electroacoustic transducer; Generate a set of candidate load values ​​for the set of adjustable load parameters; Obtain at least one set of signals indicating the bandwidth and sensitivity of the electroacoustic transducer; Perform a comparison between a sensitivity threshold and the signals in the at least one obtained signal set, and select a subset of the signals in the at least one signal set as the result of the comparison; A set of load candidate values ​​with maximum bandwidth is selected from the set of load candidate values, wherein the set of load candidate values ​​with maximum bandwidth is the set of load candidate values ​​in the set of load candidate values ​​corresponding to the bandwidth-maximizing signal, which has a relatively maximum bandwidth among the selected subset of signals indicating the bandwidth and sensitivity of the electroacoustic transducer; and The adjustable load parameter set of the adjustable load circuit is adjusted to be equal to the bandwidth-maximizing load candidate value set. The device is at least one of the following: obstacle detection device, vehicle-mounted device, echolocation device, or sound wave time-of-flight measurement device.

19. The electronic device of claim 18, wherein the processing circuitry is configured to: Generate a set of frequency values ​​distributed across a frequency range, the set of frequency values ​​including frequency values ​​equal to the resonant frequency; Based on the set of frequency values ​​and the set of load candidate values, at least one set of signals indicating the bandwidth and sensitivity of the electroacoustic transducer is obtained.

20. The electronic device of claim 19, wherein the processing circuitry is configured to obtain the at least one set of signals indicative of the bandwidth and sensitivity of the electroacoustic transducer by calculating a set of frequency responses of the electroacoustic transducer based on the set of frequency values ​​and the set of load candidate values.

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