CN116298514A - Phase difference measurement method, device and system - Google Patents
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Abstract
The invention provides a phase difference measuring method, a device and a system, comprising the following steps: acquiring two input signals, and respectively sampling the two input signals to obtain a digital sequence corresponding to the two input signals; performing frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences; respectively extracting two phases of corresponding sampling points at the maximum values of the two frequency domain signal amplitudes; the phase difference between the two input signals is determined based on the phase difference of the two phases. According to the invention, the digital sequence is obtained by carrying out analog-to-digital conversion on the input signal, the amplitude of the digital sequence is obtained by adopting frequency domain conversion, the estimated value of the frequency of the input signal is obtained by the corresponding sampling point of the maximum value of the amplitude, and then the phase difference of the input signal is obtained, so that the measuring mode is simple and the measuring precision is high. By running the main measurement program on the computer, the dependence on hardware precision is further reduced, the hardware implementation cost is low, and the overall cost is reduced while the precision is ensured.
Description
Technical Field
The invention relates to the field of digital signal processing, in particular to a phase difference measuring method, a device and a system.
Background
In some applications of digital signal processing it is desirable to measure the phase difference between multiple radio frequency signals. The traditional method is to use a high sampling rate real-time oscilloscope or network analyzer to make time-domain or frequency-domain measurements. In the prior art, the phase of two input signals is measured by adopting a phase discrimination method after mixing, the output detection result is an analog voltage proportional to the phase difference, and the two signals to be measured have the same frequency, the phase difference is very small, and the measurement accuracy is easily affected by noise. Thus, to reduce the phase difference measurement error, a higher precision measuring instrument is required.
In the related art, in order to ensure the phase difference measurement accuracy, when a high sampling rate real-time oscilloscope or a network analyzer is used for measuring the time domain or the frequency domain, a special instrument is expensive and has high requirements on the measurement environment, so that the cost is high.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defect of high cost when the phase difference measurement precision is high in the prior art, thereby providing a phase difference measurement method, a device and a system.
With reference to the first aspect, the present invention provides a phase difference measurement method, the method including:
acquiring two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
performing frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences;
respectively extracting two phases of corresponding sampling points at the maximum values of the two frequency domain signal amplitudes;
a phase difference between the two input signals is determined based on the phase difference of the two phases.
In the method, the digital sequence is obtained by carrying out analog-to-digital conversion on the input signal, the amplitude of the digital sequence is obtained by adopting frequency domain conversion, the estimated value of the frequency of the input signal is obtained by the corresponding sampling point of the maximum value of the amplitude, and then the phase difference of the input signal is obtained, so that the measuring method is simple and the measuring precision is high. The main measurement program is run on the computer, so that the hardware implementation cost is low, the dependence on hardware precision is further reduced, and the overall cost of measurement is reduced while the precision is ensured.
With reference to the first aspect, in a first embodiment of the first aspect, the sampling the two input signals respectively to obtain digital sequences corresponding to the two input signals includes:
inputting two input signals into an analog-to-digital converter;
and respectively carrying out analog-to-digital conversion on the two input signals based on the analog-to-digital converter to obtain digital sequences corresponding to the two input signals.
With reference to the first embodiment of the first aspect, in a second embodiment of the first aspect, the analog-to-digital converter samples two of the input signals by the following formula:
wherein x is i And y i Respectively corresponding digital sequences of two input signals omega 1 And omega 2 Respectively the instantaneous phases of the two input signals, f sample Is the sampling frequency of the analog-to-digital converter, t skew For the deviation of the two input signals at the sampling time, quantize is the quantization bit number of the analog-to-digital converter.
With reference to the first aspect, in a third embodiment of the first aspect, the performing frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences includes:
and performing fast Fourier transform on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences.
With reference to the first aspect, in a fourth embodiment of the first aspect, the extracting two phases of the corresponding sampling points at the maximum values of the two frequency domain signal amplitudes includes:
traversing the amplitude values of the two frequency domain signals to obtain the maximum amplitude value of the two frequency domain signals;
determining sampling points corresponding to the amplitude maximum values of the two frequency domain signals based on the amplitude maximum values of the two frequency domain signals;
and determining two phases corresponding to the two frequency domain signals corresponding to the sampling points based on the sampling points.
In a second aspect of the present invention, the present invention also provides a phase difference measuring apparatus, the apparatus comprising:
the sampling unit is used for acquiring two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
the frequency domain transformation unit is used for carrying out frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences;
the extraction unit is used for respectively extracting two phases of the corresponding sampling points at the maximum value of the two frequency domain signal amplitudes;
a determining unit for determining a phase difference between the two input signals based on the phase difference of the two phases.
With reference to the second aspect, in a first embodiment of the second aspect, the sampling unit includes:
an input unit for inputting two of the input signals to an analog-to-digital converter;
and the conversion unit is used for respectively carrying out analog-to-digital conversion on the two input signals based on the analog-to-digital converter to obtain digital sequences corresponding to the two input signals.
With reference to the first embodiment of the second aspect, in a second embodiment of the second aspect, the conversion unit includes:
a conversion subunit, configured to sample two input signals by using the following formula by using the analog-to-digital converter:
wherein x is i And y i Respectively corresponding digital sequences of two input signals omega 1 And omega 2 Respectively the instantaneous phases of the two input signals, f sample Is the sampling frequency of the analog-to-digital converter, t skew For the deviation of the two input signals at the sampling time, quantize is the quantization bit number of the analog-to-digital converter.
With reference to the second aspect, in a third embodiment of the second aspect, the frequency domain transforming unit includes:
and the fast Fourier transform unit is used for performing fast Fourier transform on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences.
With reference to the second aspect, in a fourth embodiment of the second aspect, the extracting unit includes:
the traversing unit is used for traversing the amplitude values of the two frequency domain signals to obtain the maximum amplitude value of the two frequency domain signals;
the first determining unit is used for determining sampling points corresponding to the amplitude maximum values of the two frequency domain signals based on the amplitude maximum values of the two frequency domain signals;
and the second determining unit is used for determining two phases corresponding to the two frequency domain signals corresponding to the sampling points based on the sampling points.
In a third aspect of the present invention, the present invention further provides a phase difference measurement system, the system including an analog-to-digital conversion unit, a data acquisition circuit, and a processor:
the analog-to-digital conversion unit is used for receiving two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
the data acquisition circuit is used for acquiring two digital sequences output by the analog-to-digital conversion unit and sending the two digital sequences to the processor;
the processor is used for carrying out frequency domain transformation on the two digital sequences to obtain two corresponding frequency domain signals, respectively extracting phases of sampling points corresponding to the maximum values of the amplitude values of the two frequency domain signals, and determining the phase difference between the two input signals to be detected based on the phase difference of the two phases.
With reference to the third aspect, in a first embodiment of the third aspect, the analog-to-digital conversion unit is an analog-to-digital converter.
With reference to the first embodiment of the third aspect, in a second embodiment of the third aspect, the analog-to-digital converter includes two analog-to-digital conversion channels, where the two analog-to-digital conversion channels are completely identical and are configured to receive two input signals respectively, and sample the two input signals respectively, so as to obtain digital sequences corresponding to the two input signals.
With reference to the third aspect, in a fourth embodiment of the third aspect, the processor is a computer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a phase difference measurement method according to an exemplary embodiment.
Fig. 2 is a schematic diagram of an input signal incorporating noise proposed according to an exemplary embodiment.
Fig. 3 is a schematic diagram of FFT magnitudes proposed according to an exemplary embodiment.
Fig. 4 is a schematic diagram of FFT phases proposed according to an exemplary embodiment.
Fig. 5 is a schematic diagram of a phase difference measurement system according to an exemplary embodiment.
Fig. 6 is a schematic diagram of a phase difference measurement system according to an exemplary embodiment.
Fig. 7 is a block diagram showing a structure of a phase difference measuring apparatus according to an exemplary embodiment.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the related art, in order to ensure the phase difference measurement accuracy, when a high sampling rate real-time oscilloscope or a network analyzer is used for measuring the time domain or the frequency domain, a special instrument is expensive and has high requirements on the measurement environment, so that the cost is high.
In order to solve the above problems, an embodiment of the present invention provides a phase difference measurement method, which is applicable to a use scenario. According to the phase difference measuring method provided by the invention, the digital sequence is obtained by carrying out analog-to-digital conversion on the input signal, the amplitude of the digital sequence is obtained by adopting the fast Fourier transform, and the estimated value of the frequency of the input signal is obtained by the corresponding sampling point of the maximum value of the amplitude, so that the phase difference of the input signal is obtained, the measuring mode is simple, and the measuring precision is high. The main measurement program is run on the computer, so that the hardware implementation cost is low, the dependence on hardware precision is further reduced, and the overall cost of measurement is reduced while the precision is ensured.
Fig. 1 is a flowchart of a phase difference measurement method according to an exemplary embodiment. As shown in fig. 1, the phase difference measurement method includes the following steps S101 to S104.
In step S101, two input signals are acquired, and the two input signals are sampled respectively, so as to obtain a digital sequence corresponding to the two input signals.
In the embodiment of the present invention, in order to calculate the phase difference between two input signals, the two input signals need to be sampled to obtain the digital sequences corresponding to the two input signals, which may include: inputting two input signals into an analog-to-digital converter; based on the analog-to-digital converter, analog-to-digital conversion is carried out on the two input signals respectively, and a digital sequence corresponding to the two input signals is obtained. The analog-to-digital converter samples two input signals according to the following formula:
wherein x is i And y i Respectively corresponding digital sequences of two input signals omega 1 And omega 2 Respectively the instantaneous phases of the two input signals, f sample Is the sampling frequency of the analog-to-digital converter, t skew For the deviation of the two input signals at the sampling time, quantize is the quantization bit number of the analog-to-digital converter.
In one example, assume that x (t) and y (t) are two sinusoidal input signals, the instantaneous phase ω of the sinusoidal input signal x (t) 1 Through omega 1 ＝2πf x Calculated, f x The instantaneous phase omega of the sinusoidal input signal y (t) is the frequency of the sinusoidal input signal x (t) 2 Through omega 2 ＝2πf y Calculated, f y Is the frequency of the sinusoidal input signal y (t). Quantize represents the digital-to-analog conversion of the ADC and is represented by the number of bits used. The higher the quantization bit number of a digital-to-analog converter (ADC), the more accurate the subsequent phase measurement result. Through experimental comparison, the 14bit ADC can achieve higher phase measurement accuracy while keeping low cost.
In step S102, the two digital sequences are subjected to frequency domain transformation, so as to obtain two frequency domain signals corresponding to the two digital sequences.
In the embodiment of the invention, after the digital sequence is received, in order to determine the phase of the input signal, the digital sequence is subjected to frequency domain transformation to obtain a frequency domain signal, so that the phase of the input signal is determined by using the frequency domain signal. The process of performing frequency domain transformation on the two digital sequences can obtain two frequency domain signals corresponding to the two digital sequences by performing fast fourier transformation on the two digital sequences.
In one example, the digital sequence x may be received i And y i Thereafter, their frequency and phase are estimated using an FFT-based algorithm, which can be expressed by the following formula:
X[k]＝FFT(x)
Y[k]＝FFT(y)
wherein X [ k ]]Is a digital sequence x of length K i Sequences obtained by fast fourier transformation, Y [ k ]]Is a digital sequence y of length K i Is obtained by fast fourier transformation. X [ k ]]And Y [ k ]]Are complex numbers, and the value of K is the power of 2. Let ρ be x,k Is complex number X [ k ]]Amplitude phi x,k Is complex number X [ k ]]Phase angle ρ y,k Is complex number Y [ k ]]Amplitude phi y,k Is complex number Y [ k ]]Phase angle, complex number X [ k ]]And Y [ k ]]Can be expressed as:
in step S103, two phases of the corresponding sampling points at the maximum values of the two frequency domain signal amplitudes are extracted, respectively.
In the embodiment of the invention, in order to facilitate the definition of the phase difference between the two frequency domain signals, two phases of the sampling points corresponding to the maximum values of the amplitude values of the two frequency domain signals are respectively extracted. Extracting two phases of corresponding sampling points at the maximum of the two frequency domain signal amplitudes may include: traversing the amplitude values of the two frequency domain signals to obtain the maximum amplitude value of the two frequency domain signals; determining sampling points corresponding to the maximum amplitude values of the two frequency domain signals based on the maximum amplitude values of the two frequency domain signals; based on the sampling points, two phases corresponding to the two frequency domain signals corresponding to the sampling points are determined.
In one example, the numerical sequence amplitude maximum and the corresponding sampling point k, denoted as k, can be found by the following formula max ：
The frequency corresponding to the sampling point is an estimated value of the frequency of the input sinusoidal signal, and the phase difference corresponding to the frequency can be calculated by the following formula:
where Δφ is the phase difference of the sinusoidal input signals x (t) and y (t) at the sampling point,
for the phase of the sinusoidal input signal x (t) at this sampling point +.>
For the phase of the sinusoidal input signal y (t) at that sampling point.
In step S104, a phase difference between the two input signals is determined based on the phase differences of the two phases.
In one example, the deviation of sinusoidal input signals x (t) and y (t) at the sampling instant can be calculated by the following formula:
t skew ＝Δφ/2πf
where f is the frequency of the sinusoidal input signals x (t) and y (t).
Through the embodiment, the digital sequence is obtained by carrying out analog-to-digital conversion on the input signal, the amplitude of the digital sequence is obtained by adopting frequency domain transformation, the estimated value of the frequency of the input signal is obtained by the corresponding sampling point of the maximum value of the amplitude, and then the phase difference of the input signal is obtained, and the measuring mode is simple and the measuring precision is high. The main measurement program is run on the computer, so that the hardware implementation cost is low, the dependence on hardware precision is further reduced, and the overall cost of measurement is reduced while the precision is ensured.
In an implementation scenario, to determine the validity of the phase difference measurement method provided in the foregoing embodiment, two sets of radio frequency signals with a fixed phase difference are generated by using a program and are sampled by an analog ADC through an algorithm, the generated data is calculated by using the phase difference measurement method provided in the foregoing embodiment, and the deviation between the obtained phase difference measurement value and the actual value is compared, so as to further implement verification of the validity of the phase difference measurement method provided in the foregoing embodiment.
In one example, the input signal frequency is 21MHz, the sampling frequency is 50MHz, the ADC resolution is 14bit, t skew =20ps, and a gaussian white noise of 1LSB is superimposed on the input signal, with 8192 samples as an example. Fig. 2 is a schematic diagram of an input signal incorporating noise proposed according to an exemplary embodiment. Fig. 3 is a schematic diagram of FFT magnitudes proposed according to an exemplary embodiment. Fig. 4 is a schematic diagram of FFT phases proposed according to an exemplary embodiment. The phase difference measurement is carried out on two groups of radio frequency signals with fixed phase difference generated by the following procedures:
％parameters
sig_freq＝21e6；
sam_freq＝50e6；
adc_bit＝14；
init_time＝-20e-12；
noise_amp＝1；
％some derived variable
amp_factor＝2^(adc_bit-1)；
time_index＝(0:8191)；
％phi＝2*pi*f*(N*Tsample+init_time)
sig_phi1＝2*pi*sig_freq*(time_index/sam_freq)；
sig_wave1＝sin(sig_phi1)；
sig_phi2＝2*pi*sig_freq*(time_index/sam_freq+init_time)；
sig_wave2＝sin(sig_phi2)；
％add some noise norm_noise＝noise_amp*randn(size(sig_wave1))；
sig_wave1＝sig_wave1*amp_factor+norm_noise；
norm_noise＝noise_amp*randn(size(sig_wave2))；
sig_wave2＝sig_wave2*amp_factor+norm_noise；
％simulate the effect of quantizing；
sig_wave1＝int16(sig_wave1)；
sig_wave1＝double(sig_wave1)；
sig_wave2＝int16(sig_wave2)；
sig_wave2＝double(sig_wave2)；
％now perform the FFT
sig_fft1＝fft(sig_wave1)；
sig_fft_phi1＝angle(sig_fft1)；
sig_fft_amp1＝abs(sig_fft1)；
sig_fft2＝fft(sig_wave2)；
sig_fft_phi2＝angle(sig_fft2)；
sig_fft_amp2＝abs(sig_fft2)；
delta_phi＝sig_fft_phi1-sig_fft_phi2；
delta_time＝int32(delta_phi/(2*pi*sig_freq)*1e14)；
delta_time＝double(delta_time)/100；
max_amp_index＝find(sig_fft_amp1＝＝max(sig_fft_amp1))；
first_index＝max_amp_index(1)；
delta_time(first_index-3:first_index+3)
the result of obtaining the frequency estimation is 3442 th point, and the phase differences of several points around the corresponding point are: 19.8000 20.1600 19.9900 19.9600 19.9600 20.0300 (ps) is averaged based on the phase difference of several points around the corresponding point, and the final result is that the estimation of the sampling phase error of 19.98ps and the actual value can be accurate to 1ps.
Based on the same inventive concept, the invention also provides a phase difference measurement system.
Fig. 5 is a schematic diagram of a phase difference measurement system according to an exemplary embodiment. As shown in fig. 5, the phase difference measurement system includes an analog-to-digital conversion unit 501, a data acquisition circuit 502, and a processor 503.
The analog-to-digital conversion unit 501 is configured to receive two input signals, sample the two input signals respectively, and obtain digital sequences corresponding to the two input signals;
the data acquisition circuit 502 is used for acquiring two digital sequences output by the analog-to-digital conversion unit and sending the two digital sequences to the processor;
the processor 503 is configured to perform frequency domain transformation on the two digital sequences to obtain two corresponding frequency domain signals, extract phases of sampling points corresponding to maximum values of amplitude values of the two frequency domain signals, and determine a phase difference between two input signals to be detected based on the phase difference of the two phases.
In the embodiment of the present invention, the analog-to-digital conversion unit 501 is an analog-to-digital converter; the analog-to-digital converter comprises two analog-to-digital conversion channels, wherein the two analog-to-digital conversion channels are completely consistent and are used for respectively receiving two input signals and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals; the processor 503 is a computer.
In an example, fig. 6 is a schematic diagram of a phase difference measurement system according to an exemplary embodiment, where the measurement hardware employs a dual-channel analog-to-digital conversion chip to form two completely identical digital-to-analog conversion (ADC) channels; the two radio frequency sinusoidal signals to be detected are respectively input into the two paths of ADC channels. The converted data is sent into a computer through a data acquisition circuit and is processed by a phase difference measurement algorithm based on FFT.
Based on the same inventive concept, the invention also provides a phase difference measuring device.
Fig. 7 is a block diagram showing a structure of a phase difference measuring apparatus according to an exemplary embodiment. As shown in fig. 7, the phase difference measuring apparatus includes a sampling unit 701, a frequency domain transforming unit 702, an extracting unit 703, and a determining unit 704.
The sampling unit 701 is configured to obtain two input signals, and sample the two input signals respectively to obtain digital sequences corresponding to the two input signals;
a frequency domain transforming unit 702, configured to perform frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences;
an extracting unit 703, configured to extract two phases of the sampling points corresponding to the maximum values of the two frequency domain signal amplitudes respectively;
a determining unit 704 for determining a phase difference between the two input signals based on the phase difference of the two phases.
In one embodiment, the sampling unit 701 includes: an input unit for inputting two input signals to the analog-to-digital converter; and the conversion unit is used for respectively carrying out analog-to-digital conversion on the two input signals based on the analog-to-digital converter to obtain digital sequences corresponding to the two input signals.
In another embodiment, a conversion unit includes: a conversion subunit, configured to sample the two input signals by using the following formula:
wherein x is i And y i Respectively corresponding digital sequences of two input signals omega 1 And omega 2 Respectively the instantaneous phases of the two input signals, f sample Is the sampling frequency of the analog-to-digital converter, t skew At sampling instants for two input signalsIs quantised as the number of bits of the analogue to digital converter.
In yet another embodiment, the frequency domain transforming unit 702 comprises: and the fast Fourier transform unit is used for performing fast Fourier transform on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences.
In yet another embodiment, the extraction unit 703 comprises: the traversing unit is used for traversing the amplitude values of the two frequency domain signals to obtain the maximum amplitude value of the two frequency domain signals; the first determining unit is used for determining sampling points corresponding to the amplitude maximum values of the two frequency domain signals based on the amplitude maximum values of the two frequency domain signals; and the second determining unit is used for determining two phases corresponding to the two frequency domain signals corresponding to the sampling points based on the sampling points.
The specific limitation of the above-mentioned phase difference measuring device and the beneficial effects can be referred to the limitation of the phase difference measuring method hereinabove, and will not be described herein. The various modules described above may be implemented in whole or in part by software, hardware, or a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (10)
1. A phase difference measurement method, the method comprising:
acquiring two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
performing frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences;
respectively extracting two phases of corresponding sampling points at the maximum values of the two frequency domain signal amplitudes;
a phase difference between the two input signals is determined based on the phase difference of the two phases.
2. The method according to claim 1, wherein the sampling the two input signals to obtain the digital sequences corresponding to the two input signals includes:
inputting two input signals into an analog-to-digital converter;
and respectively carrying out analog-to-digital conversion on the two input signals based on the analog-to-digital converter to obtain digital sequences corresponding to the two input signals.
3. The method of claim 2, wherein the analog-to-digital converter samples both of the input signals by the following formula:
wherein x is i And y i Respectively corresponding digital sequences of two input signals omega 1 And omega 2 Respectively the instantaneous phases of the two input signals, f sample Is the sampling frequency of the analog-to-digital converter, t skew For the deviation of the two input signals at the sampling time, quantize is the quantization bit number of the analog-to-digital converter.
4. The method according to claim 1, wherein said performing a frequency domain transform on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences comprises:
and performing fast Fourier transform on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences.
5. The method of claim 1, wherein extracting two phases of corresponding sampling points at maximum values of the two frequency domain signal amplitudes, respectively, comprises:
traversing the amplitude values of the two frequency domain signals to obtain the maximum amplitude value of the two frequency domain signals;
determining sampling points corresponding to the amplitude maximum values of the two frequency domain signals based on the amplitude maximum values of the two frequency domain signals;
and determining two phases corresponding to the two frequency domain signals corresponding to the sampling points based on the sampling points.
6. A phase difference measuring apparatus, characterized in that the apparatus comprises:
the sampling unit is used for acquiring two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
the frequency domain transformation unit is used for carrying out frequency domain transformation on the two digital sequences to obtain two frequency domain signals corresponding to the two digital sequences;
the extraction unit is used for respectively extracting two phases of the corresponding sampling points at the maximum value of the two frequency domain signal amplitudes;
a determining unit for determining a phase difference between the two input signals based on the phase difference of the two phases.
7. The phase difference measurement system is characterized by comprising an analog-to-digital conversion unit, a data acquisition circuit and a processor:
the analog-to-digital conversion unit is used for receiving two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals;
the data acquisition circuit is used for acquiring two digital sequences output by the analog-to-digital conversion unit and sending the two digital sequences to the processor;
the processor is used for carrying out frequency domain transformation on the two digital sequences to obtain two corresponding frequency domain signals, respectively extracting phases of sampling points corresponding to the maximum values of the amplitude values of the two frequency domain signals, and determining the phase difference between the two input signals to be detected based on the phase difference of the two phases.
8. The system of claim 7, wherein the analog-to-digital conversion unit is an analog-to-digital converter.
9. The system of claim 8, wherein the analog-to-digital converter comprises two analog-to-digital conversion channels, and the two analog-to-digital conversion channels are completely identical and are used for respectively receiving two input signals, and respectively sampling the two input signals to obtain digital sequences corresponding to the two input signals.
10. The system of claim 7, wherein the processor is a computer.
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