Thermoacoustic signal conditioning system and method

Abstract

This invention relates to the field of acoustic wave modulation, and proposes a thermoacoustic signal modulation system and method, including a thermoacoustic modulation device and a closed-loop feedback control circuit. The thermoacoustic modulation device includes a medium for propagating sound waves and a thermal modulation unit integrated on or near it. The thermal modulation unit has temperature-sensitive electrical characteristics, and its electrical parameters are functionally related to temperature. The closed-loop feedback control circuit is electrically connected to the thermal modulation unit, determines the current temperature state based on the real-time electrical parameters of the thermal modulation unit, and generates driving power applied to the thermal modulation unit when there is a deviation between the target control signal and the current temperature state. The closed-loop feedback control circuit applies transient overdrive power to the thermal modulation unit when the temperature deviates passively or actively from the target temperature, so as to quickly reach and lock the target temperature. This transforms temperature modulation from passive thermal relaxation to active control based on electrical feedback.

Description

Technical Field

[0001] This invention relates to the field of acoustic wave manipulation, and in particular to a thermoacoustic signal manipulation system and method. Background Technology

[0002] On-chip acoustic wave devices are widely used in radio frequency filtering, sensing, and signal processing. Utilizing the temperature-dependent properties of material mechanical parameters for thermal modulation is a common method for achieving tunable acoustic wave propagation characteristics.

[0003] However, traditional thermal control usually uses open-loop voltage or current to drive heating elements. The heating and cooling processes of the device are limited by the thermal capacity and thermal resistance of the material and structure, resulting in a long minimum time scale for tuning and difficulty in responding quickly. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to propose a thermoacoustic signal control system and method to improve the response speed of thermal control.

[0005] To achieve the above and other related objectives, the present invention proposes a thermoacoustic signal control system, characterized in that it comprises:

[0006] A thermoacoustic modulation device includes a sound wave propagation medium and a thermal control unit. The sound wave propagation medium is used to propagate sound wave signals, and the thermal control unit is integrated on or near the sound wave propagation medium for heating the sound wave propagation medium to change its sound wave propagation characteristics. The thermal control unit has temperature-sensitive electrical characteristics, and its electrical parameters are functionally related to temperature. A closed-loop feedback control circuit, electrically connected to the thermal regulation unit, is used to receive a target control signal characterizing the target temperature, and in response to the deviation between the target control signal and the current temperature state determined based on the current electrical parameters of the thermal regulation unit, generates driving power and applies it to the thermal regulation unit. The closed-loop feedback control circuit is configured such that when the current temperature state deviates from the target temperature, the closed-loop feedback control circuit applies transient overdrive power to the thermal control unit to force the thermal control unit to quickly reach and lock at the target temperature state corresponding to the target control signal. The current temperature state deviating from the target temperature includes: passive deviation of the current temperature state of the thermal control unit caused by the external environment, or active deviation caused by active change of the target control signal to set a new target temperature.

[0007] In a specific embodiment of the present invention, the closed-loop feedback control circuit includes: A driving unit is used to generate driving power and apply it to the thermal control unit; The input unit is used to send a target control signal that characterizes the target temperature. Feedback unit, the feedback unit is used to obtain the current electrical parameters of the thermal control unit; A reference unit is connected to the driving unit, and the reference unit is used to acquire target electrical parameters; The driving unit is configured to: when the current electrical parameter deviates from the target electrical parameter, the driving unit applies transient overdrive power to the thermal control unit; when the current electrical parameter does not deviate from the target electrical parameter, the driving unit applies steady-state drive power to the thermal control unit to maintain the thermal control unit at the target temperature state, wherein the transient overdrive power is greater than the steady-state drive power.

[0008] In a specific embodiment of the present invention, the closed-loop feedback control circuit includes: A first circuit, wherein a first resistor and an adjustable resistor are connected in series in the first circuit; The second circuit has a second resistor, the thermal control unit is disposed on the second circuit, the thermal control unit is connected in series with the second resistor, and the second circuit is connected in parallel with the first circuit. An amplifier circuit is provided, wherein the output terminal of the amplifier circuit is connected to one end of the first circuit and the second circuit, the first resistor and the second resistor are disposed close to the output terminal of the amplifier circuit, and the other end of the first circuit and the second circuit is grounded. A first input circuit is connected between the first resistor and the adjustable resistor, and the first input circuit is connected to one of the non-inverting input terminal and the inverting input terminal of the amplifier circuit. The second input circuit is connected between the second resistor and the thermal control unit, and is connected to either the non-inverting input terminal or the inverting input terminal of the amplifier circuit.

[0009] In a specific embodiment of the present invention, the first circuit and the first input circuit constitute the reference unit, the second circuit and the second input circuit constitute the feedback unit, the amplification circuit constitutes the driving unit, and the input unit includes the adjustable resistor.

[0010] In a specific embodiment of the present invention, the resistance ratio of the first resistor and the adjustable resistor constitutes the target electrical parameter, and the resistance ratio of the second resistor and the thermal control unit constitutes the current electrical parameter.

[0011] In a specific embodiment of the present invention, the driving unit is used to determine whether the target electrical parameter and the current electrical parameter are the same based on the voltage difference between the first input circuit and the second input circuit.

[0012] In one specific embodiment of the present invention, a signal source is connected to the first input circuit.

[0013] In a specific embodiment of the present invention, the transient overdrive power is the maximum drive power that the drive unit can output.

[0014] In a specific embodiment of the present invention, the transient overdrive power is obtained based on the difference between the target electrical parameter and the current electrical parameter, and the larger the difference, the larger the transient overdrive power.

[0015] The present invention also provides a thermoacoustic signal modulation method, applied to the aforementioned thermoacoustic signal modulation system, comprising the following steps: Acquire the target control signal characterizing the target temperature; Obtain the current electrical parameters of the thermal control unit, and determine the target electrical parameters based on the control signal; Compare the current electrical parameters with the target electrical parameters; Based on the comparison results, drive power is applied to the thermal control unit; When the current electrical parameters and the target electrical parameters are the same, the driving power is maintained as the steady-state driving power; When the current electrical parameters and the target electrical parameters are different, the driving power is increased to the transient overdrive power.

[0016] The technical advantages of this invention are as follows: By applying transient overdrive power to temperature deviations through a closed-loop control circuit, the effective response time of the system can be reduced from the traditional millisecond-level thermal relaxation time to an extremely short timescale determined by the time constant of the electrical feedback loop. This achieves an order-of-magnitude speed improvement and meets the requirements for microsecond-level fast tuning, beamforming, or frequency hopping. Simultaneously, the isothermal closed-loop system suppresses the effects of ambient temperature fluctuations, input voltage drift, and operating condition disturbances on temperature and the resulting phase / frequency drift, significantly improving modulation accuracy, repeatability, and long-term stability. Furthermore, the fast overdrive-stabilization strategy reduces overshoot or hysteresis caused by slow heating / cooling, increases control bandwidth, and reduces system jitter, thereby improving the reliability and engineering adaptability of phase, frequency, and timing control in applications such as RF filtering, phased arrays, and sensing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a thermoacoustic modulation device according to one embodiment of the present invention; Figure 2 This is a schematic diagram of the thermoacoustic signal control system according to one embodiment of the present invention; Figure 3 The curves showing the dynamic response characteristics of the acoustic modulation of the thermoacoustic signal control system in one embodiment of the present invention are as follows: (the dashed line represents the target control signal, curve 1 corresponds to the present solution, and curve 2 corresponds to the prior art).

[0019] Explanation of reference numerals in the attached diagram: 10, First circuit; 20, Second circuit; 30, Amplifier circuit; 40, First input circuit; 50, Second input circuit; 60, Signal source; 70, Sound wave propagation medium; R1, First resistor; R2, Second resistor; Rt, Adjustable resistor; RH, Thermal control unit. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0021] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and its component layout may also be more complex.

[0022] On-chip acoustic wave devices (such as surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices) are widely used in radio frequency filtering, frequency control, sensing, and signal processing due to their small size, low power consumption, and good spectral selectivity. In modern communication and radar systems, dynamically adjusting the propagation characteristics of sound waves in materials (such as sound velocity, phase, and resonant frequency) to achieve tunable filtering, phased array beamforming, or frequency hopping has become an important means to improve system flexibility and spectrum utilization efficiency.

[0023] Thermal modulation, utilizing the temperature-dependent properties of material mechanical parameters (such as the coefficient of Young's modulus with temperature), is a common method for achieving tunable sound wave propagation characteristics. By applying a localized thermal field to a device, the elastic modulus or stress state of the material can be altered, thereby causing controllable changes in sound velocity and resonant frequency. Such thermally-based tuning schemes offer advantages in terms of tuning range and repeatability, and are easily integrated with existing micro / nano fabrication processes.

[0024] However, existing thermal control schemes have significant shortcomings in practical engineering applications, hindering their widespread adoption in next-generation high-speed communication and real-time beam control systems. The main problems include: The response speed is slow. Traditional thermal control typically uses open-loop voltage or current to drive heating elements. The heating and cooling processes of the device are limited by the thermal capacity and thermal resistance of the material and structure, i.e., constrained by the inherent thermal relaxation time constant. Typical thermal relaxation times are on the order of milliseconds or even longer, causing the minimum time scale of tuning to remain on the order of milliseconds. This speed is far from meeting the microsecond or faster switching requirements of modern communication systems such as 5G / 6G in beamforming, narrowband frequency hopping, or fast frequency reuse.

[0025] Poor environmental stability. Common open-loop thermal control methods lack the ability to sense and compensate for changes in ambient temperature in real time. Ambient temperature drift or local temperature disturbances in devices can cause shifts in acoustic wave phase and resonant frequency, leading to filter passband drift, phased array phase errors, or sensor readout deviations, severely affecting communication links, beam directivity, and measurement accuracy. To ensure long-term stable operation, design margins or passive compensation alone are often insufficient to meet stringent system performance requirements.

[0026] Given the above issues, how to achieve real-time compensation for environmental disturbances while ensuring rapid response, and how to maintain integrability and reliability at the process and system levels, has become a pressing technical challenge in the field of thermal tuning of on-chip acoustic wave devices.

[0027] To solve the above technical problems, such as Figure 1-2 As shown, the present invention proposes a thermoacoustic signal modulation system, characterized in that it includes a thermoacoustic modulation device and a closed-loop feedback control circuit.

[0028] like Figure 1As shown, the thermoacoustic modulation device includes a sound wave propagation medium 70 (referring to the substrate or structure in which acoustic energy propagates) and a thermal control unit RH. The sound wave propagation medium 70 is used to propagate sound wave signals, and the thermal control unit RH is integrated on or near the sound wave propagation medium 70 to heat the sound wave propagation medium 70 to change its sound wave propagation characteristics. The thermal control unit RH has temperature-sensitive electrical characteristics, and its electrical parameters are functionally related to temperature. Temperature changes alter the material's elastic modulus, thermal stress (stress caused by limited thermal expansion), and local geometry (dimensional changes caused by thermal expansion), thereby changing the sound velocity, propagation phase, and resonance conditions, causing a controllable shift in the device's frequency / phase. The closed-loop feedback control circuit is electrically connected to the thermal regulation unit RH, and is used to receive the target control signal characterizing the target temperature, and in response to the deviation between the target control signal and the current temperature state determined based on the current electrical parameters of the thermal regulation unit RH, generate driving power and apply it to the thermal regulation unit RH. The closed-loop feedback control circuit is configured to apply transient overdrive power to the thermal control unit RH when the current temperature state deviates from the target temperature, so as to force the thermal control unit RH to quickly reach and lock at the target temperature state corresponding to the target control signal. The current temperature state deviating from the target temperature includes: passive deviation of the current temperature state of the thermal control unit RH caused by the external environment, or active deviation caused by active change of the target control signal to set a new target temperature.

[0029] During system operation, the closed-loop circuit uses the electrical parameters of the thermal control unit RH as the "intrinsic temperature sensing" quantity, and obtains the current temperature through calibration mapping. The controller (which can be a high-speed analog circuit, a DSP, MCU, or FPGA-implemented digital controller) calculates the deviation between the target and the current temperature and outputs a drive signal. For rapid response, the controller employs transient overdrive (short-term increase in heating power or pulsed drive) when a deviation exists, making the effective heating rate much higher than the natural temperature rise rate under steady-state power. Subsequently, based on the real-time measured temperature feedback, a rapid stabilization strategy (such as integral stage limiting, reverse feedthrough, pulse width / amplitude modulation, and anti-integral saturation) is used to lock the temperature near the target. To prevent exceeding the target temperature, the control circuit includes upper limit constraints and safety mechanisms (such as real-time temperature threshold comparison, maximum power / current limiting, pulse width limiting, redundant temperature detection, and over-temperature power-off), and can be linked to active cooling measures or alarm / load reduction strategies to ensure that the device does not overheat.

[0030] This scheme shifts the bottleneck of tuning speed from passive thermal relaxation (which is millisecond-level or slower and determined by material thermal capacity / thermal resistance) to a control process primarily based on the time constant of electrical measurement and control loops, such as... Figure 3 As shown, this enables orders of magnitude faster response times (effective tuning / locking times in the microsecond to sub-millisecond range, provided the hardware and topology allow); the closed-loop isothermal and overdrive-stabilization strategies significantly reduce phase / frequency shifts caused by ambient temperature drift, power supply fluctuations, or operating condition disturbances, improving modulation accuracy, repeatability, and long-term stability; the temperature upper limit constraint and power limiting mechanism prevent device overheating, reduce degradation / damage risks, and improve system reliability and engineering availability by shortening steady-state time, reducing cumulative energy consumption, and reducing frequent large oscillations. It is suitable for RF filtering, phased array beam control, and high-precision sensing scenarios that require fast switching and high stability.

[0031] In one specific embodiment of the present invention, the closed-loop feedback control circuit includes a driving unit, an input unit, a feedback unit, and a reference unit.

[0032] The input unit outputs a target control signal or corresponding target electrical parameters characterizing the target temperature; the reference unit stores or generates the target electrical parameters corresponding to the target control signal (which can be lookup table values, polynomial fitting results, or model predictions); the feedback unit measures the electrical parameters (such as resistance, voltage, current, or thermoelectric potential) of the thermal control unit RH in real time and sends the measured values ​​to the control loop; the drive unit generates and applies power to the thermal control unit RH based on the deviation between the feedback and the reference. The system can use the same thin-film element for both heating and temperature sensing, or separate heating and temperature sensing elements can be arranged. The measurement method of the feedback unit can be four-wire resistance measurement, constant current / constant voltage measurement, or bridge circuit measurement to improve accuracy and reduce self-heating interference.

[0033] The driving unit is configured to: when the current electrical parameter deviates from the target electrical parameter, the driving unit applies transient overdrive power to the thermal control unit RH; when the current electrical parameter does not deviate from the target electrical parameter, the driving unit applies steady-state drive power to the thermal control unit RH to maintain the thermal control unit RH at the target temperature state, wherein the transient overdrive power is greater than the steady-state drive power.

[0034] In the above scheme, the controller compares the current electrical parameters measured by the feedback unit with the target electrical parameters of the reference unit in real time to obtain an error signal. When an error exists, the drive unit first uses transient overdrive power (short-duration high-amplitude pulse or high current / voltage step) to drive the thermal control unit RH to rapidly change the temperature to shorten the rise time; when the measured current electrical parameters approach or reach the target value, the drive unit switches to a lower steady-state drive power to maintain the target temperature. The switching between transient overdrive and steady-state drive is determined by real-time feedback, supplemented by mechanisms such as amplitude limiting and temperature upper limit protection to prevent overshoot or overheating. The drive unit can be implemented as a constant current source, a PWM power switch (filtered or filtered + low-pass controlled), or a linear power amplifier, etc.

[0035] This scheme rapidly reaches the target temperature through short-time overdrive, thereby transforming the effective tuning time of the device from a passive thermal relaxation time into a shorter time constant determined by the electrical measurement and control loop, significantly improving the response speed. The closed-loop real-time measurement based on the electrical parameters of the thermal control unit RH itself can suppress temperature deviations caused by environmental disturbances and power supply drift, improving steady-state accuracy and repeatability. The overdrive-stabilization strategy, combined with upper limit constraints, can prevent overheating and long-term power accumulation while ensuring speed, reducing the risk of device degradation. Furthermore, it reduces system oscillation and jitter through anti-integral saturation and appropriate filtering, thus achieving a balance between rapid tuning and long-term stability.

[0036] In one specific embodiment of the present invention, such as Figure 2 As shown, the closed-loop feedback control circuit includes a first circuit 10, a second circuit 20, an amplifier circuit 30, a first input circuit 40, and a second input circuit 50.

[0037] The first circuit 10 (reference branch) consists of a first resistor R1 connected in series with an adjustable resistor Rt, used to generate an adjustable reference voltage divider or reference point. The second circuit 20 (sensing / execution branch) consists of a second resistor R2 connected in series with a thermal control unit RH (e.g., a thin-film heating element), used as the actual sensing point of the controlled quantity. One end of each branch is connected in parallel to the output of the amplifier circuit 30, and the other end is grounded. The two inputs of the amplifier circuit 30 are taken from the midpoint of the two branches through the first input circuit 40 and the second input circuit 50, respectively, thereby sending the reference voltage and the measured voltage to the amplifier for comparison. The first resistor R1 and the second resistor R2 are placed close to the amplifier output to reduce wire impedance and parasitics, ensuring the accuracy of measurement and drive. Overall, the circuit realizes the function of comparing the electrical state (voltage / resistance level) of the thermal control unit RH with the set reference voltage and adjusting the drive in a closed loop accordingly.

[0038] During operation, the amplifier circuit 30 continuously compares the reference voltage provided by the first input circuit 40 (determined by the voltage division of the first resistor R1 and the adjustable resistor Rt) with the sensing voltage provided by the second input circuit 50 (the node voltage between the second resistor R2 and the thermal control unit RH, which varies with the temperature and electrical parameters of the thermal control unit RH). When there is a deviation between the two, the amplifier output changes, thereby changing the drive voltage / current applied to the top of the two parallel branches, causing the power flowing through the thermal control unit RH to increase or decrease accordingly, until the voltage at the measured point matches the reference voltage. If a rapid rise is required, transient overdrive can be implemented: when the controller or amplifier detects that the reference is higher than the measured value, it briefly increases the output level (or amplifies the drive through an external power switch), causing the heating unit to heat up rapidly; when the measured value approaches the reference, the amplifier automatically decays to steady-state drive to maintain the target temperature. To ensure stability, appropriate filtering / phase compensation components can be added to the input or feedback path to suppress loop oscillations caused by thermal hysteresis or power stage.

[0039] In this embodiment, the target temperature setting is converted into an adjustable reference voltage / level, and the electrical response of the thermal control unit RH itself is used as a real-time measurement quantity to achieve highly integrated self-sensing closed-loop temperature control. The electrical measurement and electric drive loop can make adjustments on a timescale much shorter than the pure thermal relaxation time, and the rise time can be significantly shortened by short-pulse overdrive. The closed loop cancels out drift caused by environmental disturbances and power supply fluctuations. The target point is set by an adjustable resistor Rt, which is easy to calibrate and array. By adding limiting, upper limit detection, and fast power-off logic to the amplifier or subsequent stage, damage from overtemperature or overcurrent can be prevented.

[0040] In a specific embodiment of the present invention, the reference unit is composed of a first circuit 10 (a first resistor R1 and an adjustable resistor Rt connected in series) and a first input circuit 40, used to generate and provide a settable reference voltage / level to the amplifier, and the adjustable resistor Rt serves as the physical embodiment of the input unit to set the target temperature (or equivalent target electrical parameters); the feedback unit is composed of a second circuit 20 (a second resistor R2 and a thermal control unit RH connected in series) and a second input circuit 50, used to sample the actual electrical signal from the thermal control unit RH and send it to another input of the amplifier to reflect the current temperature state; the amplifier circuit 30 serves as a driving unit, and its output is directly connected to the top of the two parallel branches to drive the heating unit and simultaneously provide a driving voltage to the sampling circuit.

[0041] During operation, the amplifier compares the voltages (or buffered electrical quantities) provided by the reference unit and the feedback unit. When the feedback voltage is lower than the reference voltage, the amplifier output rises, increasing the current flowing through the thermal control unit RH to raise its temperature. When approaching the target, the output drops to maintain the required steady-state power. To achieve rapid target attainment, the system can temporarily apply transient overdrive (either by direct amplification of the drive by the amplifier or by a brief boost to the output by the subsequent power switch) when an error occurs. Subsequently, it automatically switches to a lower steady-state drive using real-time feedback to maintain the temperature. The input / feedback path can include phase compensation, low-pass filtering, or differential buffering to ensure loop stability. The system maps electrical quantities to temperature / acoustic parameters through calibration and sets the target value of the adjustable resistor Rt accordingly. It should be noted that the closed loop is still limited by the thermal conduction time constant; the overdrive amplitude and duration must be designed according to the thermal model and reliability constraints, and coupled with limiting protection.

[0042] In a specific embodiment of the present invention, this scheme is essentially a bridge closed-loop structure with resistance ratio as the control quantity. The reference unit is formed by a first resistor R1 (820 Ω) connected in series with an adjustable resistor Rt (0–2000 Ω), and the feedback unit is formed by a second resistor R2 (150 Ω) connected in series with a thermal control unit RH (aluminum thin film, approximately 183 Ω at room temperature). The system defines the "target electrical parameter" as R1 / Rt and the "current electrical parameter" as R2 / RH. When the two are equal, the balance condition R1 / Rt = R2 / RH is satisfied, the bridge is balanced, the operational amplifier differential input voltage is close to zero, and the output only needs to provide sustaining power. The adjustable resistor Rt is directly used as the set target (input unit), and the resistance of the thermal control unit RH changes with temperature, thereby transforming the temperature control problem into a ratio matching problem.

[0043] During operation, the mapping relationship between RH and temperature is first established through calibration. To maintain a target temperature, the adjustable resistor Rt is calculated and set to bring the bridge to equilibrium. When the actual temperature deviates, causing a change in RH, the bridge becomes unbalanced. The operational amplifier detects the difference between the two input voltages and adjusts the output level (or drives the subsequent switch) to change the power flowing through the thermal control unit RH, promoting the temperature to return to the target direction. Figure 3 As shown, a configurable transient overdrive can be used to achieve rapid rise: when a large negative difference is detected, the output voltage / duty cycle is briefly increased to accelerate the temperature rise; when approaching equilibrium, it switches to a lower steady-state power to maintain the target.

[0044] The temperature target is converted into resistance ratio matching and a local analog differential closed loop is used. The adjustable resistor Rt directly maps to the target temperature. Calibration and setting are simple and intuitive. The response of the electrical detection and drive circuit is much faster than the pure thermal relaxation time. With short pulse overdrive, the arrival time can be significantly shortened.

[0045] In one specific embodiment of the present invention, such as Figure 2As shown, a signal source 60 (signal generator) is connected to the first input circuit 40. The signal generator is used to generate a dynamic modulation voltage to provide dynamic disturbance to the bridge balance point, thereby realizing dynamic modulation of the device.

[0046] In a specific embodiment of the present invention, the transient overdrive power is the maximum drive power that the drive unit can output. This means that when the control strategy requires rapid elimination of temperature deviation, it allows the drive unit to apply the maximum energy input to the thermal regulation unit RH at its rated or short-time limit output capability. Here, "maximum" can refer to the peak output of the driver under the conditions of safety protection and device specifications (determined by the drive power supply voltage, switching device current capability, and heat dissipation capability). Using maximum transient overdrive can shorten the effective tuning time from a long constant limited by thermal inertia to a short time constant determined by power electronics and control response, thereby achieving an order-of-magnitude speed increase and rapid locking of the target temperature, significantly enhancing the system's response capability to active target changes and external disturbances.

[0047] In a specific embodiment of the present invention, the transient overdrive power is obtained based on the difference between the target electrical parameter and the current electrical parameter, wherein the larger the difference, the larger the transient overdrive power. This scheme considers the transient overdrive power as a quantity monotonically correlated with the difference between the "target electrical parameter and the current electrical parameter" (referred to as error e), that is, the larger the error, the greater the short-term energy input allowed or driven by the system to accelerate temperature changes. Here, the error can be a ratio error (such as the aforementioned R1 / Rt). R2 / RH) or a normalized / calibrated scalar. To ensure controllability and safety, the mapping relationship is usually monotonically increasing but subject to an upper limit. Adaptively adjusting the transient overdrive energy based on the error amplitude can significantly improve the system response speed and efficiency. It provides a stronger transient push for large deviations to quickly approach the target, while providing only a small drive for small deviations to avoid unnecessary shocks, thus achieving a better trade-off between accelerating the arrival at the target and suppressing overshoot. This strategy can significantly compress the effective tuning time from the millisecond level limited by thermal relaxation (it can enter the microsecond to sub-millisecond response level under low heat-container components and sufficient drive capability), while avoiding long-term overtemperature accumulation and material fatigue through restricted and graded overdrive, thus improving repeatability and long-term stability.

[0048] The present invention also provides a thermoacoustic signal modulation method, applied to the aforementioned thermoacoustic signal modulation system, comprising the following steps: S1. Obtain the target control signal characterizing the target temperature. The target control signal is the temperature setpoint or equivalent parameter that the system expects to achieve (it can also be a user-input frequency / phase target, which is mapped to obtain the temperature target). The signal source can be a host computer command, a user panel, a network-issued command, or a closed-loop external scheduler.

[0049] S2. Obtain the current electrical parameters of the thermal control unit RH, and determine the target electrical parameters based on the control signal. The current electrical parameters refer to the instantaneous measurable electrical quantity of the thermal control unit RH (typically resistance R, voltage or current value generated by thermoelectric potential), which is collected by the feedback unit and used as the basis for temperature estimation. The target electrical parameters are the conversion of the target temperature into corresponding electrical values.

[0050] S3. Compare the current electrical parameters with the target electrical parameters. The comparison yields an error, which determines the subsequent driving strategy. The comparison not only determines equality / inequality but also provides the error magnitude and direction (requiring heating or maintenance).

[0051] S4. Apply driving power to the thermal control unit RH based on the comparison result.

[0052] When the current electrical parameters and the target electrical parameters are the same, the driving power is maintained as the steady-state driving power; When the current electrical parameters and the target electrical parameters are different, the driving power is increased to the transient overdrive power.

[0053] In summary, this invention significantly reduces the effective tuning / locking time from milliseconds to sub-milliseconds or even microseconds within hardware limits by shifting the traditional tuning speed bottleneck, which is limited by passive thermal relaxation, to a time determined by electrical measurement and control loops. Simultaneously, the closed-loop real-time feedback, using the electrical parameters of the thermal control unit (RH) itself, automatically compensates for environmental temperature drift and power supply disturbances, significantly improving the steady-state accuracy, repeatability, and long-term stability of frequency / phase modulation. The error-driven, graded transient overdrive strategy prevents overshoot and device overheating while ensuring rapid response through energy and time limiting, anti-integral saturation, and redundancy protection mechanisms, thus balancing response speed and reliability. The integrated thin-film heating / sensing scheme reduces the need for external sensors and facilitates arraying and channel-level coordination (reducing system size and cost, and facilitating multi-channel timing scheduling to suppress thermal crosstalk). Overall, this invention achieves significant improvements in comprehensive performance in terms of tuning speed, modulation accuracy, robustness and scalability, and device safety and lifespan, making it suitable for applications requiring rapid switching and high stability, such as RF filtering, phased array beam control, and high-precision sensing.

[0054] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0055] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

Claims

1. A thermoacoustic signal control system, characterized in that, include: A thermoacoustic modulation device includes a sound wave propagation medium and a thermal control unit. The sound wave propagation medium is used to propagate sound wave signals, and the thermal control unit is integrated on or near the sound wave propagation medium to heat the sound wave propagation medium to change its sound wave propagation characteristics. The thermal control unit has temperature-sensitive electrical characteristics, and its electrical parameters are functionally related to temperature. as well as A closed-loop feedback control circuit, electrically connected to the thermal regulation unit, is used to receive a target control signal characterizing the target temperature, and in response to the deviation between the target control signal and the current temperature state determined based on the current electrical parameters of the thermal regulation unit, generates driving power and applies it to the thermal regulation unit. The closed-loop feedback control circuit is configured such that when the current temperature state deviates from the target temperature, the closed-loop feedback control circuit applies transient overdrive power to the thermal control unit to force the thermal control unit to quickly reach and lock at the target temperature state corresponding to the target control signal. The current temperature state deviating from the target temperature includes: passive deviation of the current temperature state of the thermal control unit caused by the external environment, or active deviation caused by active change of the target control signal to set a new target temperature.

2. The thermoacoustic signal control system according to claim 1, characterized in that, The closed-loop feedback control circuit includes: A driving unit is used to generate driving power and apply it to the thermal control unit; The input unit is used to send a target control signal that characterizes the target temperature. Feedback unit, the feedback unit is used to obtain the current electrical parameters of the thermal control unit; A reference unit is connected to the driving unit, and the reference unit is used to acquire target electrical parameters; The driving unit is configured to: when the current electrical parameter deviates from the target electrical parameter, the driving unit applies transient overdrive power to the thermal control unit; when the current electrical parameter does not deviate from the target electrical parameter, the driving unit applies steady-state drive power to the thermal control unit to maintain the thermal control unit at the target temperature state, wherein the transient overdrive power is greater than the steady-state drive power.

3. The thermoacoustic signal control system according to claim 2, characterized in that, The closed-loop feedback control circuit includes: A first circuit, wherein a first resistor and an adjustable resistor are connected in series in the first circuit; The second circuit has a second resistor, the thermal control unit is disposed on the second circuit, the thermal control unit is connected in series with the second resistor, and the second circuit is connected in parallel with the first circuit. An amplifier circuit is provided, wherein the output terminal of the amplifier circuit is connected to one end of the first circuit and the second circuit, the first resistor and the second resistor are disposed close to the output terminal of the amplifier circuit, and the other end of the first circuit and the second circuit is grounded. A first input circuit is connected between the first resistor and the adjustable resistor, and the first input circuit is connected to one of the non-inverting input terminal and the inverting input terminal of the amplifier circuit. The second input circuit is connected between the second resistor and the thermal control unit, and is connected to either the non-inverting input terminal or the inverting input terminal of the amplifier circuit.

4. The thermoacoustic signal control system according to claim 3, characterized in that, The first circuit and the first input circuit constitute the reference unit, the second circuit and the second input circuit constitute the feedback unit, the amplifier circuit constitutes the driving unit, and the input unit includes the adjustable resistor.

5. The thermoacoustic signal control system according to claim 3, characterized in that... The resistance ratio of the first resistor and the adjustable resistor constitutes the target electrical parameter, and the resistance ratio of the second resistor and the thermal control unit constitutes the current electrical parameter.

6. The thermoacoustic signal control system according to claim 3, characterized in that, The driving unit is used to determine whether the target electrical parameter and the current electrical parameter are the same based on the voltage difference between the first input circuit and the second input circuit.

7. The thermoacoustic signal control system according to claim 3, characterized in that, A signal source is connected to the first input circuit.

8. The thermoacoustic signal control system according to claim 2, characterized in that, The transient overdrive power is the maximum drive power that the drive unit can output.

9. The thermoacoustic signal control system according to claim 2, characterized in that, The transient overdrive power is obtained based on the difference between the target electrical parameters and the current electrical parameters, and the larger the difference, the greater the transient overdrive power.

10. A method for thermoacoustic signal modulation, characterized in that, The application of the thermoacoustic signal control system as described in any one of claims 1-9 includes the following steps: Acquire the target control signal characterizing the target temperature; Obtain the current electrical parameters of the thermal control unit, and determine the target electrical parameters based on the control signal; Compare the current electrical parameters with the target electrical parameters; Based on the comparison results, drive power is applied to the thermal control unit; When the current electrical parameters and the target electrical parameters are the same, the driving power is maintained as the steady-state driving power; When the current electrical parameters and the target electrical parameters are different, the driving power is increased to the transient overdrive power.

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