High-speed phase-locked amplification system based on LC resonance and control method thereof

Abstract

The invention discloses a high-speed phase-locked amplification system based on LC resonance and a control method thereof. The system comprises a microfluidic measurement module and a phase-locked amplification module. The control method comprises the following steps: applying a sinusoidal voltage signal to a to-be-measured object, and measuring conductivity and impedance information to obtain the sinusoidal voltage signal of the to-be-measured object; performing phase-locked amplification processing on the sinusoidal voltage signal of the to-be-measured object to obtain an orthogonal component of the to-be-measured voltage signal of the to-be-measured object; and performing cordic operation on the orthogonal component of the to-be-measured voltage signal of the to-be-measured object to obtain the amplitude of the to-be-measured voltage signal and the phase of the to-be-measured voltage signal. According to the embodiment of the invention, the sensitivity of the system at the resonant frequency and the detection bandwidth of the lock-in amplifier can be improved, so that the measurement bandwidth of the system is improved. The integrated amplifying circuit can be widely applied to the technical field of integrated amplifying circuits.

Description

Technical Field

[0001] The present application relates to the technical field of integrated amplifier circuits, and in particular to a high-speed phase-locked amplifier system based on LC resonance and a control method thereof. Background Art

[0002] Phase-locked amplifier technology is an AC weak signal detection technology based on coherent demodulation, which can extract the amplitude and phase of weak AC signals in a specific frequency band. Especially in a test environment with strong background noise, the high-steepness low-pass filter of the phase-locked amplifier can filter out most of the background noise and obtain a signal with a high signal-to-noise ratio.

[0003] However, the traditional phase-locked amplifier directly inputs the full-band signal and has the same sensitivity to the signals within the bandwidth. The related technology directly connects the signal of the microfluidic chip to the phase-locked amplifier through electrodes and current amplifiers; or converts it into a voltage signal through a current-to-voltage converter, and then connects it to the phase-locked amplifier through a voltage amplifier. Both of them directly amplify the current change caused by the change in the impedance of the microfluidic channel and connect it to the phase-locked amplifier. The sensitivity of the system is relatively low, which is largely restricted by the magnitude of the impedance change when the particles flow through the microfluidic channel. It is necessary to design a phase-locked amplifier with a higher signal-to-noise ratio. There are high requirements for the design of the phase-locked amplifier itself, and it is also necessary to design a smaller microfluidic chip and its electrodes to improve sensitivity. These designs are often affected by the process accuracy, and there are high requirements for the design of the microfluidic chip and electrodes.

[0004] In addition, with the continuous development of the field of microfluidic detection, its detection frequency has gradually increased to the level of hundreds of megahertz. This technology has a wide range of applications in single-cell impedance measurement. The model of single-cell impedance is composed of cell membrane impedance and cytoplasm impedance. In the low-frequency range below megahertz, the main characteristics of cell impedance are determined by the double-layer capacitance of the cell membrane; in the high-frequency range from several megahertz to hundreds of megahertz, the electrical characteristics inside the cytoplasm become the dominant factor affecting impedance. By detecting in the high-frequency range, it is possible to penetrate the cell membrane and obtain the impedance parameters inside the cytoplasm. The frequency used by the existing detection system is limited by the bandwidth of the phase-locked amplifier itself, and it is impossible to obtain hundreds of megahertz of information.

[0005] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the invention

[0006] The main purpose of the embodiments of the present application is to propose a high-speed phase-locked amplifier system based on LC resonance and a control method thereof, which can improve the sensitivity of the system at the resonant frequency and the detection bandwidth of the phase-locked amplifier, thereby improving the measurement bandwidth of the system.

[0007] To achieve the above-mentioned purpose, an embodiment of the present application proposes a high-speed phase-locked amplification system based on LC resonance, the system comprising a microfluidic measurement module and a phase-locked amplification module, the output end of the phase-locked amplification module is connected to the input end of the microfluidic measurement module, and the output end of the microfluidic measurement module is connected to the input end of the phase-locked amplification module, wherein:

[0008] The microfluidic measurement module is used to apply a sinusoidal voltage signal to the object to be measured, measure the conductivity and impedance information, and obtain the sinusoidal voltage signal of the object to be measured;

[0009] The phase-locked amplification module is used to perform phase-locked amplification processing on the sinusoidal voltage signal of the object to be measured to obtain the voltage signal to be measured of the object to be measured.

[0010] In some embodiments, the microfluidic measurement module includes a constant current pump, a microfluidic chip and a microfluidic measurement circuit, the output end of the constant current pump is connected to the input end of the microfluidic chip, and the output end of the microfluidic chip is connected to the input end of the microfluidic measurement circuit, wherein:

[0011] The constant flow pump is used to inject the object to be tested into the microfluidic chip;

[0012] The microfluidic chip is used to obtain the conductivity of the object to be measured and the impedance information of the object to be measured according to the change of the electric field distribution generated by the object to be measured;

[0013] The microfluidic measurement circuit is used to convert the conductivity of the object to be measured and the impedance information of the object to be measured to obtain a sinusoidal voltage signal of the object to be measured.

[0014] In some embodiments, the microfluidic chip comprises a microfluidic channel and an electrode, and the output end of the microfluidic channel is connected to the input end of the electrode, wherein:

[0015] The microfluidic channel is used to obtain an impedance signal of the object to be measured according to the impedance change of the object to be measured;

[0016] The electrodes are used to convert the impedance signal of the object to be measured into an electrical signal to obtain the conductivity of the object to be measured and the impedance information of the object to be measured.

[0017] In some embodiments, the microfluidic measurement circuit includes a high-frequency inductance circuit and a current-to-voltage circuit, and the output end of the high-frequency inductance circuit is connected to the input end of the current-to-voltage circuit, wherein:

[0018] The high-frequency inductance circuit is used to convert the conductivity of the object to be measured in the microfluidic channel and the impedance information of the object to be measured into a current signal to obtain a sinusoidal current signal of the object to be measured;

[0019] The current-to-voltage circuit is used to convert the sinusoidal current signal of the object to be measured into a sinusoidal voltage signal of the object to be measured.

[0020] In some embodiments, the equivalent model circuit of the high-frequency inductance circuit includes a first inductor and a first capacitor, which are connected in parallel. The equivalent model circuit of the microfluidic chip includes a first resistor and a second capacitor, which are connected in parallel. The equivalent model circuit of the current-to-voltage circuit includes a second resistor and a third capacitor, which are connected in parallel, and the second end of the second resistor and the second end of the third capacitor are both grounded.

[0021] In some embodiments, the phase-locked amplifier module includes an input channel, an output channel and a digital signal processing module, the output end of the input channel is connected to the input end of the digital signal processing module, and the output end of the digital signal processing module is connected to the input end of the output channel, wherein:

[0022] The input channel is used to obtain the sinusoidal voltage signal of the object to be tested and perform preprocessing to obtain the sinusoidal voltage digital signal of the object to be tested;

[0023] The digital signal processing module is used to demodulate and synthesize the sinusoidal voltage digital signal of the object to be tested to obtain a digital sinusoidal signal of the object to be tested;

[0024] The output channel is used to convert and output the digital sinusoidal signal of the object to be tested to obtain a voltage signal applied to the object to be tested.

[0025] In some embodiments, the input channel includes a low-noise fully differential amplifier circuit module, a first low-pass filter and an analog-to-digital signal converter, the output end of the low-noise fully differential amplifier circuit module is connected to the input end of the first low-pass filter, and the output end of the first low-pass filter is connected to the input end of the analog-to-digital signal converter, wherein:

[0026] The low-noise fully differential amplifier circuit module is used to amplify the sinusoidal voltage signal of the object to be measured to obtain an amplified sinusoidal voltage signal;

[0027] The first low-pass filter is used to filter the amplified sinusoidal voltage signal to obtain a filtered sinusoidal voltage signal;

[0028] The analog-to-digital signal converter is used to perform analog-to-digital conversion processing on the filtered sinusoidal voltage signal to obtain a sinusoidal voltage digital signal of the object to be measured.

[0029] In some embodiments, the digital signal processing module includes a digital demodulator and a digital frequency synthesizer, and the output end of the digital demodulator is connected to the input end of the digital frequency synthesizer, wherein:

[0030] The digital demodulator is used to demodulate the sinusoidal voltage digital signal of the object to be measured to obtain the amplitude information of the object to be measured and the phase information of the object to be measured;

[0031] The digital frequency synthesizer is used to generate a sinusoidal signal of an LC resonant frequency and a sinusoidal signal for coherent demodulation, so as to obtain a digital sinusoidal signal applied to the object to be measured.

[0032] In some embodiments, the output channel includes a digital-to-analog signal converter, a second low-pass filter and a power amplifier, the output end of the digital-to-analog signal converter is connected to the input end of the second low-pass filter, and the output end of the second low-pass filter is connected to the input end of the power amplifier, wherein:

[0033] The digital-to-analog signal converter is used to perform digital-to-analog conversion processing on the digital sinusoidal signal applied to the object to be tested, so as to obtain an analog sinusoidal signal applied to the object to be tested;

[0034] The second low-pass filter is used to filter the analog sinusoidal signal applied to the object to be measured to obtain a filtered analog sinusoidal signal;

[0035] The power amplifier is used to amplify the filtered analog sinusoidal signal to obtain a voltage signal applied to the object to be measured.

[0036] To achieve the above object, another aspect of the embodiment of the present application provides a control method for a high-speed phase-locked amplifier system based on LC resonance, the control method comprising the following steps:

[0037] Applying a sinusoidal voltage signal to the object to be measured, measuring conductivity and impedance information, and obtaining a sinusoidal voltage signal of the object to be measured;

[0038] Performing phase-locked amplification processing on the sinusoidal voltage signal of the object to be tested to obtain an orthogonal component of the voltage signal to be tested of the object to be tested;

[0039] A cord ic operation is performed on the orthogonal components of the voltage signal to be measured of the object to be measured to obtain the amplitude of the voltage signal to be measured and the phase of the voltage signal to be measured.

[0040] The embodiments of the present application include at least the following beneficial effects: The present application provides a high-speed phase-locked amplification system based on LC resonance and a control method thereof. The scheme uses a microfluidic measurement module to measure the conductivity and impedance of the object to be measured, has high sensitivity at the resonant frequency, and can amplify the slight impedance change in the microfluidic channel into a more obvious current phase change and amplitude change, thereby improving the sensitivity of the system at the resonant frequency. The sinusoidal voltage signal of the object to be measured is further phase-locked and amplified by the phase-locked amplification module, thereby obtaining a sampling rate several times that of a single analog-to-digital converter, thereby improving the detection bandwidth of the phase-locked amplifier and thereby improving the measurement bandwidth of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of a framework of a high-speed phase-locked amplification system based on LC resonance provided in an embodiment of the present application;

[0042] Figure 2 It is a schematic flow chart of the steps of a control method of a high-speed phase-locked amplifier system based on LC resonance provided in an embodiment of the present application;

[0043] Figure 3 is a schematic diagram of an equivalent model of a microfluidic measurement circuit provided in an embodiment of the present application;

[0044] Figure 4 It is a schematic diagram of the structure of dual analog-to-digital converter time interleaving of the input channel of the lock-in amplifier provided in an embodiment of the present application;

[0045] Figure 5 It is a schematic diagram of the structure of the microfluidic chip provided in the embodiment of the present application.

[0046] Figure numerals: 1, microfluidic measurement module; 101, constant current pump; 102, microfluidic chip; 103, high-frequency inductor circuit; 104, first power amplifier; 105, current-to-voltage circuit; 106, second power amplifier; 2, phase-locked amplifier module; 201, third power amplifier; 202, first low-pass filter; 203, digital-to-analog converter; 204, first multiplier; 205, digital frequency synthesizer; 206, first digital low-pass filter; 207, cord IC operation module; 208, computer; 209, fourth power amplifier; 210, second low-pass filter; 211, analog-to-digital converter; 212, second multiplier; 213, second digital low-pass filter; 301, equivalent model circuit of high-frequency inductor circuit; 302, equivalent model circuit of microfluidic chip; 303, equivalent model circuit of current-to-voltage circuit; 401, microfluidic channel; 402, electrode; 403, glass substrate. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of systems and methods consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0048] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

[0049] The terms "at least one", "multiple", "each", "any", etc. used in this application, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0051] Reference Figure 1 , Figure 1 A structural diagram of a high-speed phase-locked amplifier system based on LC resonance provided by an embodiment of the present invention, referring to Figure 1 The system includes a microfluidic measurement module and a phase-locked amplifier module, the output end of the phase-locked amplifier module is connected to the input end of the microfluidic measurement module, and the output end of the microfluidic measurement module is connected to the input end of the phase-locked amplifier module, wherein:

[0052] The microfluidic measurement module is used to apply a sinusoidal voltage signal to the object to be measured, measure the conductivity and impedance information, and obtain a sinusoidal voltage signal of the object to be measured;

[0053] Further, it should be noted that the microfluidic measurement module includes a constant current pump 101, a microfluidic chip 102 and a microfluidic measurement circuit, the output end of the constant current pump is connected to the input end of the microfluidic chip, and the output end of the microfluidic chip is connected to the input end of the microfluidic measurement circuit, wherein:

[0054] The constant flow pump is used to inject the object to be tested into the microfluidic chip;

[0055] The microfluidic chip is used to generate changes in the electric field distribution of the object to be measured, and obtain the conductivity and impedance information of the object to be measured;

[0056] Furthermore, it should be noted that the microfluidic chip includes a microfluidic channel 401 and an electrode 402, and the output end of the microfluidic channel is connected to the input end of the electrode, wherein the microfluidic channel is used to obtain an impedance signal of the object to be measured according to the impedance change of the object to be measured; the electrode is used to convert the impedance signal of the object to be measured into an electrical signal to obtain the conductivity of the object to be measured and the impedance information of the object to be measured.

[0057] The microfluidic measurement circuit is used to convert the conductivity of the object to be measured and the impedance information of the object to be measured to obtain a sinusoidal voltage signal of the object to be measured.

[0058] Furthermore, it should be noted that the microfluidic measurement circuit includes a high-frequency inductance circuit 103 and a current-to-voltage circuit 105, and the output end of the high-frequency inductance circuit is connected to the input end of the current-to-voltage circuit, wherein the high-frequency inductance circuit is used to convert the conductivity of the object to be measured in the microfluidic channel and the impedance information of the object to be measured into a current signal to obtain a sinusoidal current signal of the object to be measured; and the current-to-voltage circuit is used to convert the sinusoidal current signal of the object to be measured into a sinusoidal voltage signal of the object to be measured.

[0059] In this embodiment, the microfluidic measurement part includes a constant current pump, a microfluidic chip and a microfluidic measurement circuit. The constant current pump injects the object to be measured into the microfluidic chip. The microfluidic chip includes a microfluidic channel and an electrode. When the object to be measured is injected into the microfluidic channel, the impedance of the microfluidic channel changes. The electrode converts the impedance change into an electrical signal, and then connects to the lock-in amplifier through the microfluidic measurement circuit. The object to be measured will change the electric field distribution in the microfluidic channel. The object to be measured with high conductivity will cause the current passing through the object to be measured to change greatly, and the larger the object to be measured, the greater the current change. Through the above principles, the conductivity and size of the object to be measured can be measured. The microfluidic measurement circuit includes a two-stage power amplifier, which uses signal amplification as an impedance buffer between the lock-in amplifier and the microfluidic device; a high-frequency inductor, which forms a capacitor-inductor resonant circuit with the channel capacitance of the microfluidic chip, converts the flow of particles in the microfluidic channel into a change in current, and obtains a higher sensitivity at the resonant frequency; a current-to-voltage circuit, which converts the output current of the micro-body device into a voltage and provides it to the lock-in amplifier for measurement.

[0060] In addition, the equivalent model circuit 301 of the high-frequency inductor circuit includes a first inductor L and a first capacitor C L , where L is the equivalent inductance, C L The first inductor and the first capacitor are connected in parallel. The equivalent model circuit 302 of the microfluidic chip includes a first resistor R ch With the second capacitor C ch , R ch is the equivalent resistance of the microfluidic chip, C ch is the equivalent capacitor of the microfluidic chip, the first resistor and the second capacitor are connected in parallel, and the equivalent model circuit 303 of the current-to-voltage circuit includes the second resistor R in With the third capacitor C in , R in is the equivalent input resistance of the op amp, C in is the equivalent input capacitance of the operational amplifier, the second resistor and the third capacitor are connected in parallel, and the second end of the second resistor and the second end of the third capacitor are both grounded.

[0061] The phase-locked amplifier module is used to perform phase-locked amplification processing on the sinusoidal voltage signal of the object to be measured to obtain the voltage signal to be measured of the object to be measured.

[0062] Further, it should be noted that the phase-locked amplifier module includes an input channel, an output channel and a digital signal processing module, the output end of the input channel is connected to the input end of the digital signal processing module, and the output end of the digital signal processing module is connected to the input end of the output channel, wherein:

[0063] The input channel is used to obtain the sinusoidal voltage signal of the object to be tested and perform preprocessing to obtain the sinusoidal voltage digital signal of the object to be tested;

[0064] Specifically, the input channel includes a low-noise fully differential amplifier circuit module, a first low-pass filter and an analog-to-digital signal converter, the output end of the low-noise fully differential amplifier circuit module is connected to the input end of the first low-pass filter, and the output end of the first low-pass filter is connected to the input end of the analog-to-digital signal converter, wherein the low-noise fully differential amplifier circuit module is used to amplify the sinusoidal voltage signal of the object to be measured to obtain an amplified sinusoidal voltage signal; the first low-pass filter is used to filter the amplified sinusoidal voltage signal to obtain a filtered sinusoidal voltage signal; and the analog-to-digital signal converter is used to perform analog-to-digital conversion on the filtered sinusoidal voltage signal to obtain a sinusoidal voltage digital signal of the object to be measured.

[0065] The digital signal processing module is used to demodulate and synthesize the sinusoidal voltage digital signal of the object to be tested to obtain a digital sinusoidal signal of the object to be tested;

[0066] Specifically, the digital signal processing module includes a digital demodulator and a digital frequency synthesizer, wherein the output end of the digital demodulator is connected to the input end of the digital frequency synthesizer, wherein the digital demodulator is used to demodulate the sinusoidal voltage digital signal of the object to be measured to obtain the amplitude information and the phase information of the object to be measured; the digital frequency synthesizer is used to generate a sinusoidal signal of the LC resonant frequency and a sinusoidal signal for coherent demodulation to obtain a digital sinusoidal signal applied to the object to be measured.

[0067] The output channel is used to convert and output the digital sinusoidal signal of the object to be measured to obtain a voltage signal applied to the object to be measured.

[0068] Specifically, the output channel includes a digital-to-analog signal converter, a second low-pass filter and a power amplifier, wherein the output end of the digital-to-analog signal converter is connected to the input end of the second low-pass filter, and the output end of the second low-pass filter is connected to the input end of the power amplifier, wherein the digital-to-analog signal converter is used to perform digital-to-analog conversion on the digital sinusoidal signal applied to the object to be tested to obtain an analog sinusoidal signal applied to the object to be tested; the second low-pass filter is used to filter the analog sinusoidal signal applied to the object to be tested to obtain a filtered analog sinusoidal signal; and the power amplifier is used to amplify the filtered analog sinusoidal signal to obtain a voltage signal applied to the object to be tested.

[0069] In the present embodiment, the lock-in amplifier can be divided into three parts, an input channel, an output channel and a digital signal processing module. The output channel provides a high-bandwidth output signal to the microfluidic detection circuit, which converts the impedance change caused by the object to be measured into a voltage change, collects it through the input channel, and finally processes it in the digital signal processing module to obtain the phase change and amplitude change of the voltage. The input channel includes a low-noise fully differential amplifier circuit, a low-pass filter module and a high-speed analog-to-digital signal converter. The low-noise front stage adopts a multi-stage op amp cascade, which will provide a larger gain to the input signal and only introduce a small amount of noise. The low-pass filter adopts a multi-stage passive π-type filter cascade to filter out the noise outside the bandwidth and improve the signal-to-noise ratio of the signal. The high-speed analog-to-digital signal converter adopts time interleaving technology, and multiple analog-to-digital signal converters are staggered for sampling at the same time, and the signal is converted into a digital signal with a higher sampling rate, which is provided to the digital signal processing module for processing. The digital signal processing module includes a digital demodulator and a digital frequency synthesizer. The digital demodulator demodulates the digital signal into amplitude information and phase information; the digital frequency synthesizer will generate a digital sine signal of up to 800MHz according to demand, and provide it to the output channel to generate the corresponding analog sine signal. The output channel also includes a digital-to-analog signal converter, a low-pass filter and a power amplifier. The high-bandwidth digital-to-analog signal converter converts the digital sine signal into an analog sine signal. The low-pass filter uses the same structure as the input channel to filter out the step signal generated by the digital-to-analog signal converter. The power amplifier outputs the signal to the microfluidic measurement part.

[0070] See also Figure 2 The embodiment of the present application also provides a control method of a high-speed phase-locked amplifier system based on LC resonance, which can realize the above-mentioned high-speed phase-locked amplifier system based on LC resonance. The control method includes the following steps:

[0071] S100, applying a sinusoidal voltage signal to the object to be measured, measuring conductivity and impedance information, and obtaining a sinusoidal voltage signal of the object to be measured;

[0072] S200, performing phase-locked amplification processing on the sinusoidal voltage signal of the object to be measured to obtain the orthogonal component of the voltage signal to be measured of the object to be measured;

[0073] S300, performing a cord ic operation on the orthogonal components of the voltage signal to be measured of the object to be measured to obtain the amplitude and phase of the voltage signal to be measured;

[0074] In some specific embodiments, Figure 1As shown, this embodiment includes a microfluidic measurement module 1 and a phase-locked amplifier module 2. The microfluidic measurement part includes a constant current pump 101, a microfluidic chip 102, a high-frequency inductor circuit 103, a first power amplifier 104, a second power amplifier 106 and a current-to-voltage circuit 105. The specific structure of the microfluidic chip 102 is as follows: Figure 5 As shown, Figure 5 (a) is a top view of the microfluidic chip. Figure 5 (b) is a side view of the microfluidic chip, which includes a microfluidic channel 401 made of polydimethylsiloxane, with a width d of 100 um and a height of 70 um; an electrode 402 made of 10 nm chromium and 70 nm gold, with a height a of 70 nm, an electrode width w of 30 um, and an electrode spacing g of 40 um; a glass substrate 403 is an electronic grade glass substrate, and its equivalent circuit model is shown in FIG. Figure 3 As shown, the high-frequency inductor circuit 103 can be equivalent to an equivalent model circuit 301 of the high-frequency inductor circuit, where L is the inductance of the high-frequency inductor, C L is the parasitic capacitance of the high-frequency inductor, and produces a self-resonance effect with the high-frequency inductor itself; the microfluidic chip 102 can be equivalent to an equivalent model circuit 302 of the microfluidic chip, where R ch is the equivalent resistance of the microfluidic chip, including the equivalent resistance of the microfluidic channel and the equivalent resistance of the microfluidic particles, C ch It is the equivalent capacitance of the microfluidic chip, including the equivalent capacitance of the microfluidic channel, the double-layer parasitic capacitance and stray capacitance of the electrode, and the equivalent capacitance of the microfluidic particles. This capacitance will resonate with the high-frequency inductor L, greatly improving the sensitivity of the system at the resonant frequency.

[0075] The phase-locked amplifier part generates a set pair of mutually orthogonal digital sinusoidal signals by the digital frequency synthesizer 205, and provides them to the first multiplier 204, the second multiplier 212 and the digital-to-analog converter 203 respectively. The digital-to-analog converter 203 converts the digital sinusoidal signal into an analog sinusoidal signal of up to 800 MHz, and filters out the digital step signal through the first low-pass filter 202, and then outputs it to the phase-locked amplifier module 2 through the third power amplifier 201. It is injected into the high-frequency inductor circuit 103 and the microfluidic chip 102 through the first power amplifier 104, and a weak current is generated through the electrode 402. The current is converted into a voltage signal through the current-to-voltage circuit 105, and then amplified by the second power amplifier 106 to a signal sufficient for the phase-locked amplifier part to collect. The phase-locked amplifier part further amplifies the signal through the fourth power amplifier 209, and then filters out the noise outside the bandwidth through the second low-pass filter 210, and converts the collected signal into a digital signal to be measured through the analog-to-digital converter 211. The specific architecture of the analog-to-digital converter 211 is as follows. Figure 4As shown in the figure, the analog-to-digital converter includes two analog-to-digital converters, and the sampling periods of the two analog-to-digital converters are consistent, but the sampling time is staggered by half a sampling period. Through time interleaved sampling, the equivalent sampling rate can be doubled, which is equivalent to increasing the bandwidth of the system to 800MHz. Due to the mismatch between the two analog-to-digital converters, such as process errors, harmonic signals in other frequency bands will be generated under time interleaved sampling.

[0076] The signal to be tested is multiplied with the orthogonal sinusoidal signal generated by the digital frequency synthesizer 205 through the first multiplier 204 and the second multiplier 212 respectively, and the spectrum of the signal to be tested is moved to the vicinity of zero frequency. Then, the first digital low-pass filter 206 and the second digital low-pass filter 213 are used to filter out signals other than zero frequency, including the double harmonics generated by the multiplier and the harmonic signals generated by time-interleaved sampling, as well as the noise of the system itself, and then the clean X and Y components of the signal to be tested are obtained. The X and Y components are passed through the cord ic operation module 207 to obtain the amplitude R and phase Φ of the signal to be tested, and then these information are transmitted to the computer 208 for display.

[0077] Further explanation is given in conjunction with the implementation case. The particles to be tested are yeast. Other particles, such as polystyrene microspheres, can also be used. When the yeast is injected into the microfluidic chip 102 through the constant current pump 101, the yeast flows through the microfluidic channel, and its equivalent capacitance C ch And the equivalent resistance R ch The impedance of the microfluidic particles is obtained based on the magnitude and time of the change.

[0078] It can be understood that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0079] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A high-speed phase-locked amplifier system based on LC resonance, characterized in that: The system comprises a microfluidic measurement module and a phase-locked amplifier module, wherein the output end of the phase-locked amplifier module is connected to the input end of the microfluidic measurement module, and the output end of the microfluidic measurement module is connected to the input end of the phase-locked amplifier module, wherein: The microfluidic measurement module is used to apply a sinusoidal voltage signal to the object to be measured, measure the conductivity and impedance information, and obtain the sinusoidal voltage signal of the object to be measured; The phase-locked amplification module is used to perform phase-locked amplification processing on the sinusoidal voltage signal of the object to be measured to obtain the voltage signal to be measured of the object to be measured.

2. The system according to claim 1, characterized in that The microfluidic measurement module includes a constant current pump, a microfluidic chip and a microfluidic measurement circuit, the output end of the constant current pump is connected to the input end of the microfluidic chip, and the output end of the microfluidic chip is connected to the input end of the microfluidic measurement circuit, wherein: The constant flow pump is used to inject the object to be tested into the microfluidic chip; The microfluidic chip is used to obtain the conductivity of the object to be measured and the impedance information of the object to be measured according to the change of the electric field distribution generated by the object to be measured; The microfluidic measurement circuit is used to convert the conductivity of the object to be measured and the impedance information of the object to be measured to obtain a sinusoidal voltage signal of the object to be measured.

3. The system according to claim 2, characterized in that The microfluidic chip comprises a microfluidic channel and an electrode, wherein the output end of the microfluidic channel is connected to the input end of the electrode, wherein: The microfluidic channel is used to obtain an impedance signal of the object to be measured according to the impedance change of the object to be measured; The electrodes are used to convert the impedance signal of the object to be measured into an electrical signal to obtain the conductivity of the object to be measured and the impedance information of the object to be measured.

4. The system according to claim 2, characterized in that The microfluidic measurement circuit includes a high-frequency inductance circuit and a current-to-voltage circuit, and the output end of the high-frequency inductance circuit is connected to the input end of the current-to-voltage circuit, wherein: The high-frequency inductance circuit is used to convert the conductivity of the object to be measured in the microfluidic channel and the impedance information of the object to be measured into a current signal to obtain a sinusoidal current signal of the object to be measured; The current-to-voltage circuit is used to convert the sinusoidal current signal of the object to be measured into a sinusoidal voltage signal of the object to be measured.

5. The system according to claim 4, characterized in that The equivalent model circuit of the high-frequency inductance circuit includes a first inductor and a first capacitor, which are connected in parallel. The equivalent model circuit of the microfluidic chip includes a first resistor and a second capacitor, which are connected in parallel. The equivalent model circuit of the current-to-voltage circuit includes a second resistor and a third capacitor, which are connected in parallel, and the second end of the second resistor and the second end of the third capacitor are both grounded.

6. The system according to claim 1, characterized in that The phase-locked amplifier module includes an input channel, an output channel and a digital signal processing module, the output end of the input channel is connected to the input end of the digital signal processing module, and the output end of the digital signal processing module is connected to the input end of the output channel, wherein: The input channel is used to obtain the sinusoidal voltage signal of the object to be tested and perform preprocessing to obtain the sinusoidal voltage digital signal of the object to be tested; The digital signal processing module is used to demodulate and synthesize the sinusoidal voltage digital signal of the object to be tested to obtain a digital sinusoidal signal of the object to be tested; The output channel is used to convert and output the digital sinusoidal signal of the object to be tested to obtain a voltage signal applied to the object to be tested.

7. The system according to claim 6, characterized in that The input channel includes a low-noise fully differential amplifier circuit module, a first low-pass filter and an analog-to-digital signal converter, the output end of the low-noise fully differential amplifier circuit module is connected to the input end of the first low-pass filter, and the output end of the first low-pass filter is connected to the input end of the analog-to-digital signal converter, wherein: The low-noise fully differential amplifier circuit module is used to amplify the sinusoidal voltage signal of the object to be measured to obtain an amplified sinusoidal voltage signal; The first low-pass filter is used to filter the amplified sinusoidal voltage signal to obtain a filtered sinusoidal voltage signal; The analog-to-digital signal converter is used to perform analog-to-digital conversion processing on the filtered sinusoidal voltage signal to obtain a sinusoidal voltage digital signal of the object to be measured.

8. The system according to claim 6, characterized in that The digital signal processing module includes a digital demodulator and a digital frequency synthesizer, the output end of the digital demodulator is connected to the input end of the digital frequency synthesizer, wherein: The digital demodulator is used to demodulate the sinusoidal voltage digital signal of the object to be measured to obtain the amplitude information of the object to be measured and the phase information of the object to be measured; The digital frequency synthesizer is used to generate a sinusoidal signal of an LC resonant frequency and a sinusoidal signal for coherent demodulation, so as to obtain a digital sinusoidal signal applied to the object to be measured.

9. The system according to claim 6, characterized in that The output channel includes a digital-to-analog signal converter, a second low-pass filter and a power amplifier, the output end of the digital-to-analog signal converter is connected to the input end of the second low-pass filter, and the output end of the second low-pass filter is connected to the input end of the power amplifier, wherein: The digital-to-analog signal converter is used to perform digital-to-analog conversion processing on the digital sinusoidal signal applied to the object to be tested, so as to obtain an analog sinusoidal signal applied to the object to be tested; The second low-pass filter is used to filter the analog sinusoidal signal applied to the object to be measured to obtain a filtered analog sinusoidal signal; The power amplifier is used to amplify the filtered analog sinusoidal signal to obtain a voltage signal applied to the object to be measured.

10. A control method for a high-speed phase-locked amplifier system based on LC resonance, characterized in that: The control method comprises the following steps: Applying a sinusoidal voltage signal to the object to be measured, measuring conductivity and impedance information, and obtaining a sinusoidal voltage signal of the object to be measured; Performing phase-locked amplification processing on the sinusoidal voltage signal of the object to be tested to obtain an orthogonal component of the voltage signal to be tested of the object to be tested; A cordic operation is performed on the orthogonal components of the voltage signal to be measured of the object to be measured to obtain the amplitude of the voltage signal to be measured and the phase of the voltage signal to be measured.

Images