Device and method for calibrating multipath delay parameter of channel simulator

Abstract

The invention discloses a device and a method for calibrating multipath delay parameters of a channel simulator, and relates to the technical field of wireless communication. Comprising an arbitrary waveform generator, an up-converter, a power divider, a channel simulator, a digital oscilloscope, a reference clock, a computer and a calibration reference plane. The method can avoid or improve the defects of the time domain pulse technology for calibrating the multipath delay parameter of the channel simulator, and provides a channel simulator multipath delay parameter calibration result with higher precision and larger bandwidth for the fields of broadband digital communication, 5G / 6G communication, radar signal processing, Internet of Things and the like.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to an apparatus and method for calibrating multipath delay parameters of a channel simulator. Background Technology

[0002] The rapid development of wireless communication technology has placed higher demands on the testing of communication equipment. Channel simulators, as core components in the testing of wireless communication equipment, play a crucial role in the research and verification of modern communication systems. Channel simulators can accurately simulate various characteristics of real wireless propagation environments, including multipath effects, Doppler shift, path loss, and shadowing fading, providing a near-realistic testing environment for communication equipment.

[0003] In multipath delay simulation, channel simulators simulate the superposition effect of electromagnetic waves propagating along different paths by replicating signals and applying different time delays. Multipath delay parameters directly affect key performance indicators of communication systems, such as bit error rate and throughput. In 5G and future communication systems, due to the use of higher frequency bands and larger bandwidth transmission signals, the impact of multipath delay parameters will be even more significant. Therefore, accurate measurement and calibration of multipath delay parameters are crucial to ensuring the performance of channel simulators.

[0004] Currently, commonly used channel simulator multipath delay parameter calibration techniques are mainly based on time-domain pulse technology. By exciting the signal with a time-domain pulse signal, the time-domain waveform can be directly observed to evaluate delay characteristics. According to the uncertainty principle, time-domain resolution is inversely proportional to signal bandwidth. Since pulse signals require pulse shaping and filtering, their resolution is limited. Therefore, time-domain pulse technology is difficult to apply to test scenarios that require distinguishing minute delay differences in dense multipath environments. Secondly, time-domain pulse technology, relying on single measurements, is severely affected by random noise interference, impacting the accurate detection of pulse peaks. To improve measurement accuracy, multiple measurements and averaging are often required, resulting in low testing efficiency. A major problem with calibration systems based on time-domain pulse technology is that the system's own response (such as cable delay and device response) introduces measurement errors that are difficult to completely eliminate. This results in multipath delay parameter measurements only showing relative delays, failing to accurately assess performance characteristics. Furthermore, time-domain pulse technology requires precise control of pulse timing, making the measurement process complex. For complex multipath scenarios, repeated adjustments to test parameters are necessary, hindering rapid automated testing. With the development of 5G technology, the requirements for bandwidth and accuracy of future communication systems will continue to increase. The calibration method based on time-domain pulses can no longer meet the calibration requirements for multipath delay parameters of channel simulators. Summary of the Invention

[0005] The purpose of this application is to provide an apparatus and method for calibrating multipath delay parameters of a channel simulator, which can avoid or improve the shortcomings of time-domain pulse technology in calibrating multipath delay parameters of a channel simulator, and provide more accurate and wider bandwidth calibration results for multipath delay parameters of channel simulators in fields such as broadband digital communication, 5G / 6G communication, radar signal processing, and the Internet of Things.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] This application provides an apparatus for calibrating multipath delay parameters of a channel simulator, comprising: an arbitrary waveform generator, an upconverter, a power divider, a channel simulator, a digital oscilloscope, a reference clock, a computer, and a calibration reference plane;

[0008] The arbitrary waveform generator is used to receive standard multi-sine wave data generated by computer algorithms, convert it into an analog signal for output, and receive a clock synchronization signal from a reference clock input.

[0009] The upconverter is used to receive standard multi-sine signals output by an arbitrary waveform generator, set the carrier frequency fR and gain G according to the target requirements, and generate radio frequency signals for multipath delay parameter calibration of the channel simulator.

[0010] The power divider is used to receive the radio frequency signal generated by the upconverter and split it into two signals, which are then input to the channel simulator and the digital oscilloscope, respectively.

[0011] The channel simulator is used to receive one signal output from the power divider, set its path loss, coarse delay and fine delay, and output an RF signal with multipath delay characteristics.

[0012] The digital oscilloscope is used to receive two signals: one directly output from the power divider and the other after passing through a channel simulator. It samples the waveform data of the signals according to a certain sampling rate and transmits the obtained signal waveform data to a computer for data processing via a network cable.

[0013] The aforementioned reference clock is used to generate three reference clock signals at a frequency of 10MHz, which are respectively input to an arbitrary waveform generator, an upconverter, and a digital oscilloscope to achieve time base synchronization. It can synchronously generate and acquire standard multi-sine signals.

[0014] The computer generates a standard multi-sine wave signal with a center frequency of fI, a bandwidth of B, and a frequency interval of f0 according to a software algorithm. The phase relationship of this multi-sine wave signal is set to a random or linear distribution, and the amplitude of each sinusoidal component remains uniform. It can be used as a transmission signal to calibrate the multipath delay parameters of the channel simulator. The computer controls the upconverter to set the intermediate frequency signal frequency fI according to the standard multi-sine wave signal generated by the software algorithm, the upconverter output frequency fR according to the target carrier frequency, and the upconverter gain according to the link budget. The computer controls a digital oscilloscope to acquire the multi-sine wave signal waveform data in memory and perform corresponding processing, including time-domain signal preprocessing, Fourier transform, frequency response calculation of the channel simulator, and multipath delay parameter extraction.

[0015] The calibration reference surface is located at the front end of the channel simulator input port. Through the device's self-calibration settings and self-calibration process, the inherent delay of the channel simulator can be calibrated.

[0016] On the other hand, this application provides a method for calibrating multipath delay parameters in a channel simulator, comprising:

[0017] Determine the required channel simulator frequency range for calibration, including the center frequency f. R Bandwidth B, frequency range;

[0018] Determine the frequency interval f0 and the standard multi-sine signal period T;

[0019] The center frequency of the standard multi-sinusoidal signal is determined by the intermediate frequency f of the upconverter. I Sure;

[0020] Determine the sampling rate f of the arbitrary waveform generator awg , requires f awg ≥2.5*(f I +B / 2), standard multi-sine signal time sampling interval t s ;

[0021] Determine the sampling time T of the standard multi-sine signal s =(t s 2t s 3t s ,…,mt s ), where mt s The moment when the period T of the multisine signal is less than or equal to the maximum value.

[0022] Determine the standard multisine signal frequency components F = (kf0, (k+1)f0, ..., lf0), where kf0 is greater than or equal to f I -B / 2's least order harmonic, lf0 is less than or equal to f I The maximum order harmonic of +B / 2;

[0023] Determine the amplitude M = (1,1,1,…,1) at each frequency component of the standard multisine signal, with a matrix size of 1×(l-k+1);

[0024] Determine the phase P = (P1, P2, P3, ..., P) at each frequency component of the standard multisine signal. l-k+1 ), where P i = i(i-1) / (l-k+1) 2 , i = 1, 2, 3, ... l-k+1;

[0025] Determine the time-domain waveform of the standard multisine signal w = (w1, w2, w3, ..., w m ),in

[0026] The reference clock generates three clock reference signals, which are respectively input to the arbitrary waveform generator, the upconverter, and the digital oscilloscope to synchronize the time base of the three instruments.

[0027] Computer software algorithms generate standard multi-sine wave data w, which is uploaded to an arbitrary waveform generator and converted into an analog signal output to the up-converter.

[0028] The upconverter receives standard multi-sine signals as intermediate frequency signals and sets the center frequency f of the output signal according to the target carrier frequency. R The gain G is set according to the link budget, and the required RF signal is output to calibrate the multipath delay parameters of the channel simulator.

[0029] The power divider splits the RF signal into two signals, one of which is directly input to a digital oscilloscope as a reference signal. ref One path uses the direct connection method to input the channel simulator's conducted link and then inputs it to a digital oscilloscope as the test signal w. test The inherent delay of the calibration device is calibrated.

[0030] Set the digital oscilloscope sampling rate to f osc The trigger levels of the two channels are set according to the amplitude of the acquired waveform, and the acquired time-domain signal waveform data w ref [n]、w test [n], where n is the sampling point index, is uploaded to the computer for algorithm processing. The two signals are generated synchronously through a reference clock signal, and the first sampling point w of the signal is acquired according to the trigger level of the two channels. ref [n1]、w test [n2], calculate the inherent delay of the calibration device. Record the result τ sys ;

[0031] The power divider splits the RF signal into two paths: one path is directly input to a digital oscilloscope as a reference signal w1, and the other path is input to the digital oscilloscope as a test signal w2 after passing through a conductive link containing a channel simulator. The channel simulator sets the center frequency f according to the test requirements. R Bandwidth B, multipath number n, multipath delay τ;

[0032] Set the digital oscilloscope sampling rate f osc The sampling bandwidth B and the number of sampling points L determine the time resolution. and sampling time window length To meet the multipath delay parameter calibration requirements, the digital oscilloscope acquisition mode is set to single acquisition.

[0033] The computer receives waveform data w1 and w2 transmitted from the digital oscilloscope, performs windowing and filtering preprocessing on them respectively, and then performs Fourier transform to obtain the corresponding frequency response W1 = (W 11 W 12 W 13 ,…,W 1m W2(W) 21 W 22 W 23 ,…,W 2m );

[0034] Calculate the frequency response H = (H1, H2) of the channel simulator. 2, H 3, …,H m ), where H i =W 1i / W 2i , i = 1, 2, 3, ..., m;

[0035] The time-domain impulse response h = (h1, h2) of the channel simulator is calculated by performing an inverse discrete Fourier transform on H. 2, h 3, …,h m ),in i = 1, 2, 3, ..., l-k+1, where the peak position corresponds to the multipath delay;

[0036] By correcting the measured multipath delay values ​​for inherent device delay, the calibration results of the multipath delay parameters of the channel simulator can be obtained.

[0037] Based on the above technical solution, this application can achieve the following technical effects:

[0038] The first innovation is in the calibration device itself, which integrates an arbitrary waveform generator, up-converter, power divider, digital oscilloscope, reference clock, and computer. The power divider introduces a reference channel to achieve self-calibration of the device's inherent delay. The digital oscilloscope acquires the reference and test signals, and the multipath delay parameters of the channel simulator are calibrated through frequency domain response transformation. The second innovation is in the calibration method, which uses an arbitrary waveform generator and up-converter to generate multiple sinusoidal signals to meet the multipath delay parameter calibration requirements of high-frequency, high-bandwidth signals. The self-calibration step of the calibration device eliminates the inherent delay, and software algorithms perform frequency domain response calculation and inverse transformation processing on the reference and test signals to obtain the calibration results of the channel simulator's multipath delay parameters.

[0039] This allows us to avoid or improve upon the shortcomings of time-domain pulse technology in calibrating multipath delay parameters of channel simulators, providing more accurate and wider-bandwidth calibration results for multipath delay parameters of channel simulators in fields such as broadband digital communication, 5G / 6G communication, radar signal processing, and the Internet of Things. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a device for calibrating multipath delay parameters in a channel simulator according to an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the measurement result of the inherent delay of the calibration device after the self-calibration process provided in an embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the calibration results of the multipath delay parameters of the channel simulator provided in an embodiment of this application.

[0043] Arbitrary waveform generator 1, upconverter 2, power divider 3, channel simulator 4, digital oscilloscope 5, reference clock 6, computer 7, calibration reference plane 8. Detailed Implementation

[0044] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to scale, and are only used to facilitate and clarify the illustration of the embodiments of the present application.

[0045] It should be noted that, in order to clearly illustrate the content of this application, several embodiments are provided to further explain the different implementations of this application. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the following embodiments can be referred to in the preceding embodiments.

[0046] Example 1

[0047] like Figure 1 The device for calibrating multipath delay parameters of a channel simulator, as shown, includes: an arbitrary waveform generator 1, an upconverter 2, a power divider 3, a channel simulator 4, a digital oscilloscope 5, a reference clock 6, a computer 7, and a calibration reference surface 8.

[0048] The arbitrary waveform generator 1 is used to receive standard multi-sine wave data generated by the algorithm of computer 7, convert it into an analog signal for output, and receive the clock synchronization signal input by reference clock 6.

[0049] The upconverter 2 is used to receive the standard multi-sine signal output by the arbitrary waveform generator 1, set the carrier frequency fR and gain G according to the target requirements, and generate the radio frequency signal for the multipath delay parameter calibration of the channel simulator 4.

[0050] The power divider 3 is used to receive the radio frequency signal generated by the upconverter 2 and split it into two signals, which are respectively input to the channel simulator 4 and the digital oscilloscope 5.

[0051] The channel simulator 4 is used to receive one signal output from the power divider 3, set the path loss, coarse delay and fine delay for it, and output an RF signal with multipath delay characteristics.

[0052] The digital oscilloscope 5 is used to receive two signals: one directly output from the power divider 3 and the other after passing through the channel simulator 4. It samples the waveform data of the signals according to a certain sampling rate and transmits the obtained signal waveform data to the computer 7 for data processing via a network cable.

[0053] The reference clock 6 is used to generate three reference clock signals at a frequency of 10MHz, which are respectively input to the arbitrary waveform generator 1, the upconverter 2 and the digital oscilloscope 5 to achieve the effect of time base synchronization, and can synchronously generate and acquire standard multi-sine signals.

[0054] The computer 7 generates a standard multi-sine wave signal with a center frequency of fI, a bandwidth of B, and a frequency interval of f0 according to a software algorithm. The phase relationship of this multi-sine wave signal is set to a random or linear distribution, and the amplitude of each sinusoidal component remains uniform. It can be used as a transmission signal to calibrate the multipath delay parameters of the channel simulator 4. The computer 7 controls the up-converter 2 to set the intermediate frequency signal frequency fI according to the standard multi-sine wave signal generated by the software algorithm, the up-converter output frequency fR according to the target carrier frequency, and the up-converter gain according to the link budget. The computer 7 controls the digital oscilloscope 5 to acquire the multi-sine wave signal waveform data in the memory and perform corresponding processing, including time-domain signal preprocessing, Fourier transform, frequency response calculation of the channel simulator 4, and multipath delay parameter extraction.

[0055] The calibration reference surface 8 is located at the front end of the channel simulator input port. It can calibrate the inherent delay of the channel simulator 4 through the device's self-calibration settings and self-calibration process.

[0056] In summary, this device can avoid or improve the shortcomings of time-domain pulse technology in calibrating multipath delay parameters of channel simulators, and provide more accurate and wider bandwidth calibration results for multipath delay parameters of channel simulators in fields such as broadband digital communication, 5G / 6G communication, radar signal processing, and the Internet of Things.

[0057] Example 2

[0058] This embodiment utilizes the above-described device to implement a method for calibrating multipath delay parameters in a channel simulator. The specific steps are as follows:

[0059] a) Determine the required channel simulator frequency range for calibration, with the center frequency f R The frequency range is 39.5GHz to 40.5GHz, with a bandwidth of 1GHz and a frequency B of 40GHz.

[0060] b) Determine the frequency interval f0 as 10kHz, and the standard multisine signal period T = 1 / f0, which is 100μs;

[0061] c) Determine the center frequency of the standard multi-sinusoidal signal, which is determined by the intermediate frequency f of the upconverter. I Confirmed, it's 3GHz;

[0062] d) Determine the sampling rate f of the arbitrary waveform generator awg For a speed of 25 GSa / s, f is required. awg ≥2.5*(f I +B / 2), standard multi-sine signal time sampling interval t s =1 / f awg 40ps;

[0063] e) Determine the standard multisine signal sampling time T s =(t s 2t s 3t s ,…,mt s ), where mt s The maximum time when the period T of the multisine signal is less than or equal to 100 μs;

[0064] f) Determine the standard multisine signal frequency components F = (kf0, (k+1)f0, ..., lf0), where kf0 is greater than or equal to f I The lowest order harmonic of -B / 2, i.e., 39.5 GHz, is lf0, which is less than or equal to f. IThe maximum order harmonic of +B / 2 is 40.5 GHz;

[0065] g) Determine the amplitude M = (1,1,1,…,1) at each frequency component of the standard multisine signal, with a matrix size of 1×(l-k+1);

[0066] h) Determine the phase P = (P1, P2, P3, ..., P) at each frequency component of the standard multisine signal. l-k+1 ), where P i = i(i-1) / (l-k+1) 2 , i = 1, 2, 3, ... l-k+1;

[0067] i) Determine the standard multisine signal time-domain waveform w = (w1, w2, w3, ..., w m ),in

[0068] j) The reference clock generates three 10MHz clock reference signals, which are respectively input to the arbitrary waveform generator, the upconverter, and the digital oscilloscope to synchronize the time base of the three instruments;

[0069] k) Computer software algorithms generate standard multi-sine wave data w, upload it to an arbitrary waveform generator, and convert it into an analog signal output to the up-converter;

[0070] l) The upconverter receives standard multi-sine signals as intermediate frequency signals and sets the output signal center frequency f according to the target carrier frequency. R =40GHz, set gain G=10dB according to link budget, and output the radio frequency signal required for multipath delay parameter calibration of the channel simulator;

[0071] m) The power divider splits the RF signal into two signals, one of which is directly input to the digital oscilloscope as a reference signal. w ref One path uses a direct connection to the conductive link where the channel simulator is located (bypassing the channel simulator at the reference calibration plane and directly connecting to the subsequent coaxial cable) and then inputs it to a digital oscilloscope as the test signal w. test The inherent delay of the calibration device is calibrated.

[0072] n), set the digital oscilloscope sampling rate to f osc =100GSa / s, set the trigger levels of the two channels to 10mV and 20mV respectively according to the amplitude of the acquired waveform, and transfer the acquired time-domain signal waveform data w ref [n]、w test [n] (n is the sampling point index) is uploaded to the computer for algorithm processing. The two signals are generated synchronously through a reference clock signal. The first sampling point w of the signal is collected according to the trigger level of the two channels. ref[n1]、w test [n2], calculate the inherent delay of the calibration device. Record the result τ sys =18.32ns, the test result is as follows Figure 2 As shown;

[0073] o) The power divider splits the RF signal into two signals. One signal is directly input to the digital oscilloscope as a reference signal w1, and the other signal is input to the digital oscilloscope as a test signal w2 after passing through a conductive link containing a channel simulator. The channel simulator sets the center frequency f according to the test requirements. R =40GHz, bandwidth B=1GHz, multipath number n=3, multipath delay τ=(5.000μs, 5.010μs, 5.015μs);

[0074] p) Set the digital oscilloscope sampling rate to f osc =100GSa / s, sampling bandwidth is B = 1GHz, number of sampling points is L = 10Mpst, determine the time resolution. and sampling time window length To meet the multipath delay parameter calibration requirements, the digital oscilloscope acquisition mode is set to single acquisition.

[0075] q) The computer receives waveform data w1 and w2 transmitted from the digital oscilloscope, performs windowing and filtering preprocessing on them respectively, and then performs Fourier transform to obtain the corresponding frequency response W1 = (W 11 W 12 W 13 ,…,W 1m W2(W) 21 W 22 W 23 ,…,W 2m );

[0076] r) Calculate the frequency response H = (H1, H2) of the channel simulator. 2, H 3, …,H m ), where H i =W 1i / W 2i , i = 1, 2, 3, ..., m;

[0077] s) Perform inverse discrete Fourier transform on H to calculate the time-domain impulse response h = (h1, h2) of the channel simulator. 2, h 3, …,h m ),in i = 1, 2, 3, ..., l-k+1, where the peak position corresponds to the multipath delay;

[0078] By correcting the measured multipath delay values ​​for inherent device delay, the calibration results of the channel simulator's multipath delay parameters can be obtained. The measurement results are recorded as τ = (5.001μs, 5.011μs, 5.016μs). The measurement results are as follows: Figure 3 As shown.

[0079] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A device for calibrating multipath delay parameters in a channel simulator, characterized in that, include: Arbitrary waveform generator, upconverter, power divider, channel simulator, digital oscilloscope, reference clock, computer, calibration reference plane; The arbitrary waveform generator is used to receive standard multi-sine wave data generated by computer algorithms, convert it into an analog signal for output, and receive a clock synchronization signal from a reference clock input. The upconverter is used to receive standard multi-sine signals output by an arbitrary waveform generator, set the carrier frequency fR and gain G according to the target requirements, and generate radio frequency signals for multipath delay parameter calibration of the channel simulator. The power divider is used to receive the radio frequency signal generated by the upconverter and split it into two signals, which are then input to the channel simulator and the digital oscilloscope, respectively. The channel simulator is used to receive one signal output from the power divider, set its path loss, coarse delay and fine delay, and output an RF signal with multipath delay characteristics. The digital oscilloscope is used to receive two signals: one directly output from the power divider and the other after passing through a channel simulator. It samples the waveform data of the signals according to a certain sampling rate and transmits the obtained signal waveform data to a computer for data processing via a network cable. The aforementioned reference clock is used to generate three reference clock signals at a frequency of 10MHz, which are respectively input to an arbitrary waveform generator, an upconverter, and a digital oscilloscope to achieve time base synchronization. It can synchronously generate and acquire standard multi-sine signals. The computer generates a standard multi-sine wave signal with a center frequency of fI, a bandwidth of B, and a frequency interval of f0 according to a software algorithm. The phase relationship of this multi-sine wave signal is set to a random or linear distribution, and the amplitude of each sinusoidal component remains uniform. It can be used as a transmission signal to calibrate the multipath delay parameters of the channel simulator. The computer controls the upconverter to set the intermediate frequency signal frequency fI according to the standard multi-sine wave signal generated by the software algorithm, the upconverter output frequency fR according to the target carrier frequency, and the upconverter gain according to the link budget. The computer controls a digital oscilloscope to acquire the multi-sine wave signal waveform data in memory and perform corresponding processing, including time-domain signal preprocessing, Fourier transform, frequency response calculation of the channel simulator, and multipath delay parameter extraction. The calibration reference surface is located at the front end of the channel simulator input port. Through the device's self-calibration settings and self-calibration process, the inherent delay of the channel simulator can be calibrated.

2. A method for calibrating multipath delay parameters in a channel simulator, characterized in that, include: Determine the required channel simulator frequency range for calibration, including the center frequency f. R Bandwidth B, frequency range; Determine the frequency interval f0 and the standard multi-sine signal period T; The center frequency of the standard multi-sinusoidal signal is determined by the intermediate frequency f of the upconverter. I Sure; Determine the sampling rate f of the arbitrary waveform generator awg , requires f awg ≥2.5*(f I +B / 2), standard multi-sine signal time sampling interval t s ; Determine the sampling time T of the standard multi-sine signal s =(t s 2t s 3t s ,…,mt s ), where mt s The moment when the period T of the multisine signal is less than or equal to the maximum value. Determine the standard multisine signal frequency components F = (kf0, (k+1)f0, ..., lf0), where kf0 is greater than or equal to f I -B / 2's least order harmonic, lf0 is less than or equal to f I The maximum order harmonic of +B / 2; The amplitude M = (1,1,1,…,1) at each frequency component of the standard multisine signal is determined, and the matrix size is 1×(l-k+1); Determine the phase P = (P1, P2, P3, ..., P) at each frequency component of the standard multisine signal. l-k+1 ), where P i = i(i-1) / (l-k+1) 2 , i = 1, 2, 3, ... l-k+1; Determine the time-domain waveform of the standard multisine signal w = (w1, w2, w3, ..., w m ),in The reference clock generates three clock reference signals, which are respectively input to the arbitrary waveform generator, the upconverter, and the digital oscilloscope to synchronize the time base of the three instruments. Computer software algorithms generate standard multi-sine wave data w, which is uploaded to an arbitrary waveform generator and converted into an analog signal output to the up-converter. The upconverter receives standard multi-sine signals as intermediate frequency signals and sets the center frequency f of the output signal according to the target carrier frequency. R The gain G is set according to the link budget, and the required RF signal is output to calibrate the multipath delay parameters of the channel simulator. The power divider splits the RF signal into two signals, one of which is directly input to a digital oscilloscope as a reference signal. ref One path uses the direct connection method to input the channel simulator's conducted link and then inputs it to a digital oscilloscope as the test signal w. test The inherent delay of the calibration device is calibrated. Set the digital oscilloscope sampling rate to f osc The trigger levels of the two channels are set according to the amplitude of the acquired waveform, and the acquired time-domain signal waveform data w ref [n]、w test [n], where n is the sampling point index, is uploaded to the computer for algorithm processing. The two signals are generated synchronously through a reference clock signal, and the first sampling point w of the signal is acquired according to the trigger level of the two channels. ref [n1]、w test [n2], calculate the inherent delay of the calibration device. Record the result τ sys ; The power divider splits the RF signal into two paths: one path is directly input to a digital oscilloscope as a reference signal w1, and the other path is input to the digital oscilloscope as a test signal w2 after passing through a conductive link containing a channel simulator. The channel simulator sets the center frequency f according to the test requirements. R Bandwidth B, multipath number n, multipath delay τ; Set the digital oscilloscope sampling rate f osc The sampling bandwidth B and the number of sampling points L determine the time resolution. and sampling time window length To meet the multipath delay parameter calibration requirements, the digital oscilloscope acquisition mode is set to single acquisition. The computer receives waveform data w1 and w2 transmitted from the digital oscilloscope, performs windowing and filtering preprocessing on them respectively, and then performs Fourier transform to obtain the corresponding frequency response W1 = (W 11 W 12 W 13 ,…,W 1m W2(W) 21 W 22 W 23 ,…,W 2m ); Calculate the frequency response H = (H1, H2) of the channel simulator. 2, H 3, …,H m ), where H i =W 1i / W 2i , i = 1, 2, 3, ..., m; The time-domain impulse response h = (h1, h2) of the channel simulator is calculated by performing an inverse discrete Fourier transform on H. 2, h 3, …,h m ),in The peak position corresponds to the multipath delay; By correcting the measured multipath delay values ​​for inherent device delay, the calibration results of the multipath delay parameters of the channel simulator can be obtained.

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