CN116633323A - Response characteristic calibration method and system of high-speed digital acquisition system based on photoconductive technology - Google Patents

Abstract

The invention discloses a method for calibrating the response characteristics of a high-speed digital acquisition system based on photoconductive technology, which belongs to the technical field of high-speed digital signal processing; the method includes: it is characterized in that it includes the following steps: generating an ultrafast pulse signal x(t) by laser ;Use the high-speed digital acquisition system to measure the ultra-fast pulse signal x(t), and obtain the time-domain measurement result y(t); according to the ultra-fast pulse signal x(t) and the time-domain measurement result y(t), solve the high-speed digital The frequency domain response characteristic H(jω) and the time domain response characteristic of the acquisition system; the response characteristic is formed according to the frequency domain response characteristic H(jω) and the time domain response characteristic. The invention also includes a high-speed digital acquisition system response characteristic calibration system based on photoconductive technology. The invention uses femtosecond laser to excite semiconductor material to generate ultrafast pulse signal, which is used to calibrate the response characteristic of high-speed digital acquisition system, so that it can accurately describe the measured signal through deconvolution method.

Description

Method and system for calibrating response characteristics of high-speed digital acquisition system based on photoconductive technology

technical field

The invention relates to the technical field of high-speed digital signal processing, and specifically includes a method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology.

Background technique

High-speed digital acquisition systems usually include digital real-time oscilloscopes, digital sampling oscilloscopes, high-speed data acquisition cards, and communication signal analyzers. Its response characteristics include time domain response and frequency domain response. The time domain response mainly refers to the impulse response of the system, which is usually characterized by the rise time or fall time parameter of the impulse response waveform; the frequency domain response includes the amplitude-frequency response (amplitude-frequency Response) and phase-frequency response (phase-frequency response), the 3dB index of amplitude-frequency response is usually used to characterize the system bandwidth.

1. High-speed digital acquisition system and its response characteristics:

The high-speed digital acquisition system is used to collect and analyze high-speed transmission signals. It has the characteristics of wide frequency bandwidth and high sampling rate. It is widely used in military, aerospace, aviation, railway, machinery and many other industries. Typical high-speed digital acquisition systems include: broadband oscilloscopes (broadband sampling oscilloscopes, broadband real-time oscilloscopes), high-speed data acquisition cards, communication signal analyzers, etc. The bandwidth of the current high-speed digital acquisition system can reach the order of hundreds of gigahertz.

High-speed signals are usually measured by a large-bandwidth digital acquisition system. In order to improve the measurement accuracy of the system response, the bandwidth of the high-speed digital acquisition system needs to be more than three times the bandwidth of the measured signal. When the 3 times bandwidth condition is satisfied, the measurement error introduced by the high-speed digital acquisition system in the measurement result can be ignored. However, with the development of ultra-high-speed and ultra-wideband electronic information technology, the bandwidth of transmission signals continues to increase, and it is difficult for the bandwidth of high-speed digital acquisition systems to reach the measurement conditions of 3 times the relationship, and the errors generated will seriously affect the accuracy of measurement results. In order to break through the technical bottleneck of low measurement accuracy due to insufficient measurement bandwidth, digital deconvolution technology is applied to the correction of measurement results, so as to achieve high-precision calculation of system response functions.

2. Calibration of response characteristics of high-speed digital acquisition system:

There are three main methods for calibrating the response characteristics of high-speed digital acquisition systems: standard pulse method, NTN (Nose-to-nose) method and ultrafast pulse deconvolution method.

(1) Standard pulse method

The standard pulse method is to use a standard pulse source whose rise time is more than 3 times higher than the transient response time of the high-speed digital acquisition system under test to generate a standard pulse signal, and the high-speed digital acquisition system measures the rise time of this pulse signal as the time domain response characteristic. The magnitude-frequency response of the high-speed digital acquisition system is measured by frequency sweep method as the frequency domain response characteristic. This method also has certain limitations:

When the bandwidth of the high-speed digital acquisition system reaches more than 30GHz, it is difficult to realize the standard pulse source whose rise time is better than 3 times, and there are few devices on the market;

Unable to solve the time-domain response waveform of the high-speed digital acquisition system;

The phase-frequency response characteristics of the high-speed digital acquisition system cannot be obtained.

(2) NTN method

In some high-speed digital acquisition systems (such as Keysight's 86100 series sampling oscilloscopes in the United States), when the DC bias voltage is not zero, a very narrow electrical pulse signal will be generated at the input terminal. The pulse shape is proportional to the impulse response of the system sampling circuit, called "kick-out" pulse. The NTN method uses the "kick-out" pulse characteristics to connect three high-speed digital acquisition systems in pairs to achieve three measurements, and then extracts the respective response functions of the three high-speed digital acquisition systems through deconvolution calculations to achieve system response. characteristic calibration. This method has certain limitations:

Only applicable to the calibration of the response characteristics of the 86100 series broadband sampling oscilloscope produced by Keysight Corporation of the United States;

The uncertainty introduced by NTN validity is large;

The calibration results of the phase-frequency response characteristics are discrete and unstable.

The bandwidth of the high-speed digital acquisition system that can be calibrated is limited. At present, my country's national metrology benchmark measurement capability of pulse waveform parameters based on the NTN method is 50GHz.

(3) Ultrafast pulse deconvolution method

With the development of optoelectronic technology, the application of femtosecond laser technology has further improved the response speed of electrical pulses. However, even if the high-speed pulses generated by optoelectronic technology reach the picosecond level, the high-speed digital acquisition system with a bandwidth of the millimeter wave level still cannot meet the three times requirement of the standard pulse method. According to the signal and system theory, if the waveform of the standard pulse signal is known, even if the bandwidth of the standard pulse signal is less than three times that of the high-speed digital acquisition system under test, the deconvolution signal processing technology can also convert the high-speed digital acquisition system The impulse response is calculated to obtain the bandwidth and transient response index of the high-speed digital acquisition system. The prerequisite for the realization of the ultrafast pulse deconvolution method is that the waveform data of the standard pulse signal needs to be measured with high precision.

3. Photoconductive technology:

When a semiconductor material is exposed to light, its own carrier concentration changes due to the absorption of photons, resulting in a change in the conductivity of the material. This phenomenon is called the photoconductive effect. When the photon energy is greater than the forbidden band width of the semiconductor material, electron-hole pairs will be generated in the semiconductor material, and the excited carriers can be accelerated under the action of an external electric field to generate current and release electromagnetic waves. Ultrafast electrical pulse signals can be generated using photoconductive technology.

4. Generation of standard pulse signal:

There are two methods for generating standard pulse signals: circuit method and photoelectric method.

The circuit method is based on the circuit method to generate a standard pulse signal. At present, there are two ways to generate faster rise (fall) time, namely: step recovery diode and nonlinear transmission line compression technology. The method based on the step recovery diode can generate an ultrafast pulse signal with a rise time of tens of picoseconds to hundreds of picoseconds. Nonlinear transmission line compression technology can generate ultrafast pulse signals with a fall time of several picoseconds, and the signal bandwidth can reach the order of terahertz.

The optoelectronic method is based on femtosecond laser excitation of optoelectronic devices to generate ultrafast pulse waveforms. NIST in the United States generated ultrafast pulse signals based on femtosecond laser excitation of commercial photodetectors with a 3dB bandwidth of 100GHz. German PTB generates ultrafast pulse signals based on femtosecond laser excitation of low-temperature gallium arsenide photoconductive switches, and the signal bandwidth can reach the order of terahertz.

Contents of the invention

The purpose of the present invention is to provide a method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology that can accurately describe the measured signal.

In order to solve the above-mentioned technical problems, the present invention provides a method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology, comprising the following steps:

Generate ultrafast pulse signal x(t) by laser;

Measure the ultrafast pulse signal x(t) through a high-speed digital acquisition system to obtain the time domain measurement result y(t);

According to the ultrafast pulse signal x(t) and the time domain measurement result y(t), the frequency domain response characteristic H(jω) and the time domain response characteristic are calculated;

The response characteristic is formed according to the frequency domain response characteristic H(jω) and the time domain response characteristic.

Preferably, according to the ultrafast pulse signal x(t) and the time domain measurement result y(t), the frequency domain response characteristic H(jω) and the time domain response characteristic are solved, specifically including the following steps:

Perform Fourier transform and deconvolution processing on the ultrafast pulse signal x(t) and the time domain measurement result y(t) to obtain the frequency domain response characteristic H(jω);

Inverse Fourier transform and integral operation are performed on the frequency domain response characteristic H(jω) to obtain the time domain response characteristic.

Preferably, Fourier transform and deconvolution processing are performed on the ultrafast pulse signal x(t) and the time domain measurement result y(t) to obtain the frequency domain response characteristic H(jω), which specifically includes the following steps:

Perform Fourier transform on the ultrafast pulse signal x(t) to obtain the first frequency domain result X(jω);

Carry out Fourier transform to the time domain measurement result y(t), obtain the second frequency domain result Y(jω);

Perform deconvolution processing on the first frequency domain result X(jω) and the second frequency domain result Y(jω) to obtain the frequency domain response characteristic H(jω).

Preferably, inverse Fourier transform and integral operation are carried out to frequency domain response characteristic H (jω), obtain time domain response characteristic, specifically comprise the following steps:

Inverse Fourier transform is performed on the frequency domain response characteristic H(jω) to obtain the impulse response h(t);

Integrate the impulse response h(t) to obtain the step response s(t);

According to the impulse response h(t) and the step response s(t), the time domain response characteristics are obtained.

Preferably, according to the impulse response h(t) and the step response s(t), the time-domain response characteristics are obtained, which specifically includes the following steps:

The time-domain response characteristic is constituted according to the rise/fall time of the impulse response h(t) and the step response s(t).

Preferably, deconvolution processing is performed on the first frequency domain result X(jω) and the second frequency domain result Y(jω) to obtain the frequency domain response characteristic H(jω), and the specific calculation formula is:

H(jω)=Y(jω)/X(jω)

Where: |H(ω)| is the amplitude-frequency response characteristic of the high-speed digital acquisition system, It is the phase-frequency response characteristic of the high-speed digital acquisition system.

Preferably, the ultrafast pulse signal x(t) is generated by laser, which specifically includes the following steps:

Ultrafast pulse signals are generated by exciting semiconductor materials with femtosecond lasers.

Preferably, the laser is a femtosecond laser.

The present invention also provides a high-speed digital acquisition system response characteristic calibration system based on photoconductive technology, including:

An ultrafast pulse signal generation module, used to generate an ultrafast pulse signal x(t) by laser;

The time-domain measurement module is used to measure the ultra-fast pulse signal x(t) through the high-speed digital acquisition system to obtain the time-domain measurement result y(t);

The characteristic calculation module is used to calculate the frequency domain response characteristic H(jω) and the time domain response characteristic according to the ultrafast pulse signal x(t) and the time domain measurement result y(t);

The response characteristic construction module is used for constructing the response characteristic according to the frequency domain response characteristic H(jω) and the time domain response characteristic.

Compared with prior art, the beneficial effect of the present invention is:

The invention uses femtosecond laser to excite the semiconductor material to generate an ultrafast pulse signal, which has a bandwidth of terahertz order, and is used to calibrate the response characteristics of the high-speed digital acquisition system, so that it can accurately describe the measured signal through the deconvolution method .

Description of drawings

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is the data acquisition and the data processing flow schematic diagram of fast pulse signal generation, high-speed digital acquisition system response characteristic calibration in embodiment 1;

Fig. 2 is the structural representation of photoconductive chip;

Fig. 3 is a schematic structural diagram of a transmission line;

Fig. 4 is a schematic flowchart of a method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology according to the present invention.

Detailed ways

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described here, and those skilled in the art can make similar extensions without violating the connotation of the present invention, so the present invention is not limited by the specific implementations disclosed below.

Terms used in one or more embodiments of this specification are for the purpose of describing specific embodiments only, and are not intended to limit one or more embodiments of this specification. As used in one or more embodiments of this specification and the appended claims, the singular forms "a", "the", and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and/or" used in one or more embodiments of the present specification refers to and includes any or all possible combinations of one or more associated listed items.

It should be understood that although the terms first, second, etc. may be used to describe various information in one or more embodiments of the present specification, the information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, the first may also be referred to as the second, and similarly, the second may also be referred to as the first without departing from the scope of one or more embodiments of the present specification. Depending on the context, the word "if" as used herein may be interpreted as "at" or "when" or "in response to a determination."

Below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in Figure 4, the present invention provides a method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology, comprising the following steps:

Generate ultrafast pulse signal x(t) by laser;

Measure the ultrafast pulse signal x(t) through a high-speed digital acquisition system to obtain the time domain measurement result y(t);

According to the ultrafast pulse signal x(t) and the time domain measurement result y(t), the frequency domain response characteristic H(jω) and the time domain response characteristic are calculated;

The response characteristic is formed according to the frequency domain response characteristic H(jω) and the time domain response characteristic.

Preferably, according to the ultrafast pulse signal x(t) and the time domain measurement result y(t), the frequency domain response characteristic H(jω) and the time domain response characteristic are solved, specifically including the following steps:

Perform Fourier transform and deconvolution processing on the ultrafast pulse signal x(t) and the time domain measurement result y(t) to obtain the frequency domain response characteristic H(jω);

Inverse Fourier transform and integral operation are performed on the frequency domain response characteristic H(jω) to obtain the time domain response characteristic.

Preferably, Fourier transform and deconvolution processing are performed on the ultrafast pulse signal x(t) and the time domain measurement result y(t) to obtain the frequency domain response characteristic H(jω), which specifically includes the following steps:

Perform Fourier transform on the ultrafast pulse signal x(t) to obtain the first frequency domain result X(jω);

Carry out Fourier transform to the time domain measurement result y(t), obtain the second frequency domain result Y(jω);

Perform deconvolution processing on the first frequency domain result X(jω) and the second frequency domain result Y(jω) to obtain the frequency domain response characteristic H(jω).

Preferably, inverse Fourier transform and integral operation are carried out to frequency domain response characteristic H (jω), obtain time domain response characteristic, specifically comprise the following steps:

Inverse Fourier transform is performed on the frequency domain response characteristic H(jω) to obtain the impulse response h(t);

Integrate the impulse response h(t) to obtain the step response s(t);

According to the impulse response h(t) and the step response s(t), the time domain response characteristics are obtained.

Preferably, according to the impulse response h(t) and the step response s(t), the time-domain response characteristics are obtained, which specifically includes the following steps:

The time-domain response characteristic is constituted according to the rise/fall time of the impulse response h(t) and the step response s(t).

Preferably, deconvolution processing is performed on the first frequency domain result X(jω) and the second frequency domain result Y(jω) to obtain the frequency domain response characteristic H(jω), and the specific calculation formula is:

H(jω)=Y(jω)/X(jω)

Where: |H(ω)| is the amplitude-frequency response characteristic of the high-speed digital acquisition system, It is the phase-frequency response characteristic of the high-speed digital acquisition system.

Preferably, the ultrafast pulse signal x(t) is generated by laser, which specifically includes the following steps:

The semiconductor material is excited by a femtosecond laser to generate an ultrafast pulse signal x(t).

Preferably, the laser is a femtosecond laser.

The present invention also provides a high-speed digital acquisition system response characteristic calibration system based on photoconductive technology, including:

An ultrafast pulse signal generation module, used to generate an ultrafast pulse signal x(t) by laser;

The time-domain measurement module is used to measure the ultra-fast pulse signal x(t) through the high-speed digital acquisition system to obtain the time-domain measurement result y(t);

The characteristic calculation module is used to calculate the frequency domain response characteristic H(jω) and the time domain response characteristic according to the ultrafast pulse signal x(t) and the time domain measurement result y(t);

The response characteristic construction module is used for constructing the response characteristic according to the frequency domain response characteristic H(jω) and the time domain response characteristic.

In order to better illustrate the technical effects of the present invention, the present invention provides the following specific examples to illustrate the above technical process:

Embodiment 1. A method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology:

The present invention mainly includes: ultrafast pulse signal generation, data acquisition and data processing of high-speed digital acquisition system response characteristic calibration, as shown in FIG. 1 .

The ultrafast pulse signal is generated based on photoconductive technology, and the core of photoconductive technology is the photoconductive chip. The photoconductive chip is composed of a semiconductor material and a transmission line. The femtosecond laser excites the semiconductor material, and due to the existence of the photoconductive effect, an ultrafast pulse signal is generated. The ultra-fast pulse signal is coupled into the high-speed digital acquisition system through the transmission line of the photoconductive chip. The high-speed digital acquisition system completes the data acquisition of the ultra-fast pulse signal. Based on the ultra-fast pulse signal generated by the photoconductive technology and the measurement results of the high-speed digital acquisition system, the response characteristics of the high-speed digital acquisition system are obtained through data processing. Data processing includes: Fourier transform, deconvolution method, inverse Fourier transform, integral operation, etc.

1. Ultrafast pulse signal generation:

Ultrafast pulse waveforms are generated by exciting semiconductor materials with femtosecond lasers. The semiconductor material is included in the prepared photoconductive chip, and the photoconductive chip includes three parts: a base part, a photoconductive part, and a signal transmission part, as shown in FIG. 2 . Wherein, the photoconductive part is excited by the femtosecond laser to generate an ultrafast pulse signal, and the signal is transmitted by the signal transmission part.

1) Design and fabrication of photoconductive chip:

The signal transmission part is composed of a transmission line, and the material of the transmission line is gold. The transmission line structure is shown in Figure 3, in which, the width of the ground line is ≥100 μm, the width of the signal line is ≥20 μm, and the photoconductive gap is ≥10 μm (the femtosecond laser is loaded into the photoelectric through the photoconductive gap. Guide part), the distance between the signal line and the ground line is ≥15μm, the length of the transmission line is ≥500μm, and the thickness of the transmission line is ≥0.5μm.

The thickness of the photoconductive part is more than or equal to 1 μm, and the photoconductive part is a low-temperature gallium arsenide crystal, and the growth temperature is 200° C. to 300° C.

The thickness of the base part is greater than or equal to 300 μm, and the material of the base part is semi-insulating gallium arsenide crystal.

2) Laser selection:

Lasers are used to excite semiconductor materials to produce ultrafast pulse waveforms. The laser adopts femtosecond laser, the laser pulse width is ≤100fs, the laser wavelength is 800nm-900nm, and the laser output power is 200mW-400mW.

2. Calibration of response characteristics of high-speed digital acquisition system:

The ultrafast pulse signal x(t) is coupled into the high-speed digital acquisition system through the transmission line of the photoconductive chip, collected by the high-speed digital acquisition system, and the time domain measurement result y(t) is obtained.

The response characteristics of the high-speed digital acquisition system are obtained by the following steps:

1) Perform Fourier transform on the ultrafast pulse signal x(t) to obtain the first frequency domain result X(jω);

2) Measure the ultrafast pulse signal x(t) through the high-speed digital acquisition system to obtain the time-domain measurement result y(t); perform Fourier transform on the measured result y(t) of the high-speed digital acquisition system to obtain the second frequency domain result Y(jω);

3) Based on the first frequency domain result X(jω) and the second frequency domain result Y(jω), the frequency domain response characteristic H(jω) of the high-speed digital acquisition system is obtained by the deconvolution method:

H(jω)=Y(jω)/X(jω)

in:

|H(ω)| is the amplitude-frequency response characteristic of the high-speed digital acquisition system, is the phase-frequency response characteristic of the high-speed digital acquisition system;

4) The frequency domain response characteristic H(jω) of the high-speed digital acquisition system, the impulse response h(t) of the high-speed digital acquisition system is obtained through the inverse Fourier transform method;

5) Integrating the impulse response h(t), the step response s(t) of the high-speed digital acquisition system can be obtained;

6) The rise/fall times of the impulse response h(t) and the step response s(t) constitute the time-domain response characteristics of the high-speed digital acquisition system;

7) The frequency domain response characteristic H(jω) in step 3) and the time domain response characteristic in step 6) constitute the response characteristic of the high-speed digital acquisition system.

In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the modules, modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units , modules or components may be combined or may be integrated into another device, or some features may be omitted, or not implemented.

The units may or may not be physically separated, and a component displayed as a unit may be one physical unit or multiple physical units, that is, it may be located in one place, or may be distributed to multiple different places. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

In particular, according to the disclosed embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product, which includes a computer program carried on a computer-readable medium, where the computer program includes program codes for executing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network via the communication part, and/or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), the above-mentioned functions defined in the method of the present invention are performed. It should be noted that the computer-readable medium mentioned above in the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination thereof.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, program segment, or portion of code that contains one or more logical functions for implementing specified executable instructions. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or they may sometimes be executed in the reverse order, depending upon the functionality involved. It should also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by a dedicated hardware-based system that performs the specified functions or operations , or may be implemented by a combination of dedicated hardware and computer instructions.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or replacements within the technical scope disclosed in the present invention shall be covered within the protection scope of the present invention . Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (9)

1. based on photoconductive technology high-speed digital acquisition system response characteristic calibration method, it is characterized in that, comprising the following steps: Generate ultrafast pulse signal x(t) by laser; Measure the ultrafast pulse signal x(t) through a high-speed digital acquisition system to obtain the time domain measurement result y(t); According to the ultrafast pulse signal x(t) and the time domain measurement result y(t), the frequency domain response characteristic H(jω) and the time domain response characteristic are calculated; The response characteristic is formed according to the frequency domain response characteristic H(jω) and the time domain response characteristic. 2. the method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology according to claim 1, is characterized in that, according to the ultrafast pulse signal x (t) and time domain measurement result y (t), solve the frequency domain response The characteristic H(jω) and the time domain response characteristic specifically include the following steps: Perform Fourier transform and deconvolution processing on the ultrafast pulse signal x(t) and the time domain measurement result y(t) to obtain the frequency domain response characteristic H(jω); Inverse Fourier transform and integral operation are performed on the frequency domain response characteristic H(jω) to obtain the time domain response characteristic. 3. according to claim 2 based on photoconductive technology high-speed digital acquisition system response characteristic calibration method, it is characterized in that, ultrafast pulse signal x (t) and time domain measurement result y (t) are carried out Fourier transform and Deconvolution processing to obtain the frequency domain response characteristic H(jω), specifically includes the following steps: Perform Fourier transform on the ultrafast pulse signal x(t) to obtain the first frequency domain result X(jω); Carry out Fourier transform to the time domain measurement result y(t), obtain the second frequency domain result Y(jω); Perform deconvolution processing on the first frequency domain result X(jω) and the second frequency domain result Y(jω) to obtain the frequency domain response characteristic H(jω). 4. according to claim 3 based on photoconductive technology high-speed digital acquisition system response characteristic calibration method, it is characterized in that, frequency domain response characteristic H (jω) is carried out inverse Fourier transform and integral operation, obtains time domain response characteristic , including the following steps: Inverse Fourier transform is performed on the frequency domain response characteristic H(jω) to obtain the impulse response h(t); Integrate the impulse response h(t) to obtain the step response s(t); According to the impulse response h(t) and the step response s(t), the time domain response characteristics are obtained. 5. the method for calibrating response characteristics of high-speed digital acquisition systems based on photoconductive technology according to claim 4, is characterized in that, according to impulse response h (t) and step response s (t), obtain time-domain response characteristics, specifically Include the following steps: The time-domain response characteristic is constituted according to the rise/fall time of the impulse response h(t) and the step response s(t). 6. The method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology according to claim 3, wherein deconvolution is carried out to the first frequency domain result X (jω) and the second frequency domain result Y (jω) Processing to obtain the frequency domain response characteristic H(jω), the specific calculation formula is: H(jω)=Y(jω)/X(jω) Where: |H(ω)| is the amplitude-frequency response characteristic of the high-speed digital acquisition system, It is the phase-frequency response characteristic of the high-speed digital acquisition system. 7. the method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology according to claim 1, is characterized in that, produces ultrafast pulse signal x (t) by laser, specifically comprises the following steps: The semiconductor material is excited by a femtosecond laser to generate an ultrafast pulse signal x(t). 8. the method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology according to claim 1, characterized in that: The laser is a femtosecond laser. 9. A system for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology, for realizing the method for calibrating response characteristics of a high-speed digital acquisition system based on photoconductive technology as described in any one of claims 1-8, characterized in that it comprises: An ultrafast pulse signal generation module, used to generate an ultrafast pulse signal x(t) by laser; The time-domain measurement module is used to measure the ultra-fast pulse signal x(t) through the high-speed digital acquisition system to obtain the time-domain measurement result y(t); The characteristic calculation module is used to calculate the frequency domain response characteristic H(jω) and the time domain response characteristic according to the ultrafast pulse signal x(t) and the time domain measurement result y(t); The response characteristic construction module is used for constructing the response characteristic according to the frequency domain response characteristic H(jω) and the time domain response characteristic.