CN115473538B - Method and device for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data - Google Patents
Method and device for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data Download PDFInfo
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Abstract
The invention discloses a method and a device for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data, which comprise the following steps: step one, a signal transmitting end outwards transmits comb spectrum signals; step two, after receiving the double-sideband frequency signals from the transmitting end, the receiving end of the reference antenna and the receiving end of the main antenna respectively modulate the double-sideband frequency signals of the transmitting end by the double-sideband signals of the receiving end, and then generate a multi-frequency main path signal and a reference path signal; and step three, mixing the multi-frequency main path signal and the reference path signal, performing FFT cross correlation operation to obtain FFT complex data, and performing high-speed data acquisition on the cross correlation operation. The invention can realize the functions of dual-channel large-data high-speed real-time multi-frequency FFT cross-correlation operation, including dual-channel data acquisition, multi-frequency FFT real-time correlation operation, data splicing and extraction, large-rate acquisition data uploading and the like, so as to realize the surface type accurate evaluation of a large-scale and high-precision antenna.
Description
Technical Field
The invention belongs to the technical field of telescope information processing, and particularly relates to a method and a device for realizing real-time cross-correlation of high-speed multi-frequency and double-channel data.
Background
Typically, the aperture antenna of the radio telescope is parabolic. If an ideal parabolic surface, there is a point source emission source at the focal point, and the emission signal is reflected by the parabolic surface, and the wave front phase values reaching the aperture plane are equal everywhere (because the optical path distances from the focal point to the aperture plane are equal). In reality, however, the antenna surface is not a perfectly ideal parabolic surface, so that the phases in the aperture plane are not necessarily equal, and in the case of a known signal source wavelength, by detecting this phase difference, a small difference between the antenna surface and the ideal parabolic surface can be theoretically determined. In the process of measuring a panel of a radio telescope antenna, the caliber of a measured antenna (main antenna) is often huge, and is generally in a range of several meters to several tens of meters, and in order to obtain a phase difference, an antenna with a smaller caliber is used or another horn antenna is added on the measured antenna as a reference to calculate the phase difference of two paths so as to invert the phase difference of the port-surface field of the antenna and further obtain the surface shape and the error distribution of the port-surface field. Near field holographic measurement is a method for measuring the surface shape of a panel of a radio telescope by adopting the thought, as shown in figure 1. In near field holographic measurement, a phase correlation method is used to measure the amplitude and phase (i.e. vector pattern) of the radiation pattern of the antenna.
The signal frequency of the existing near-field holographic measurement transmitting source is single frequency, and the measuring process is easily influenced by multipath effects, so that the measuring results of different frequencies are inconsistent. The influence of multipath effects can be corrected by averaging the profile distributions obtained by holographic measurements at different frequencies, respectively. Because of the need of multiple measurements, the process is long, and systematic errors possibly caused by deformation of the antenna surface shape due to gravity, temperature, wind load and other factors are not eliminated in the process, so that new errors are introduced. Therefore, the multi-frequency simultaneous measurement can be used for obtaining a plurality of main path signals and reference path signals with different frequencies at one time, so that the panel surface shape of the antenna to be measured can be measured rapidly. However, since multi-frequency measurement is to introduce signals of multiple frequencies at once, it is necessary to study how to make the signals not interfere with each other and how to collect the uploaded data quickly.
Disclosure of Invention
Aiming at the problems, the invention provides a method and a device for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a method for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data comprises the following steps:
step one, a signal transmitting end adopts a comb spectrum signal as a beacon source, and the comb spectrum signal is modulated by a double sideband signal of the transmitting end and then is sent out;
step two, after receiving the transmitting end double sideband frequency signals by the receiving ends of the reference antenna and the main antenna, modulating the transmitting end double sideband frequency signals by the respective receiving end double sideband signals respectively to generate a multi-frequency main path signal and a reference path signal;
step three, mixing the multi-frequency main path signal and the reference path signal to obtain intermediate frequency signals, converting the two paths of intermediate frequency signals to generate digital quantity data, performing FFT cross correlation operation to obtain FFT complex data,
step four, carrying out high-speed data acquisition on the cross-correlation operation:
assuming that the FFT sampling frequency is fs, the sampling point number is Ns, and if the integration time is T, the calculation formula of the number of frames NumAcc is
When the FFT cross-correlation operation in the third step is started, judging whether the accumulated times of FFT samples reach NumAcc,
if the data is not reached, writing cross-correlation operation into the memory M1 to obtain FFT complex data, when the accumulated times are larger than NumAcc, writing the cross-correlation operation into the memory M2 to obtain FFT complex data, setting the memory read M2 as enabling when writing the data into the memory M1, namely reading the data of the memory M2 into a first-in first-out (FIFO) queue FIFO, otherwise setting the memory read M1 as enabling when writing the data into the memory M2, namely reading the data of the memory M1 into the FIFO, and enabling each moment to have the data flow to the FIFO to form a ping-pong transmission mode of the data;
and fifthly, uploading data acquisition in the FIFO.
In some embodiments, in the first step, the comb spectrum signal is generated by Matlab programming, labview programming is adopted, the comb spectrum signal is loaded to the intermediate frequency IF transceiver module and sent out from the analog output port, the fixed sampling frequency of the intermediate frequency IF transceiver module is 3.2GHz, and the data length of the fixed sampling frequency is exactly one whole period of the comb spectrum frequency interval.
In some of these embodiments, the frequency interval Δf of the comb spectrum signal is set to be an integer multiple of the FFT spectrum interval, i.e., Δf=nf s N, N is a positive integer, N is the FFT length.
In some embodiments, the comb spectrum signal and the transmitting end local oscillator signal generate a transmitting end double sideband signal consisting of a transmitting end upper sideband signal and a transmitting end lower sideband signal, and then the double sideband signal is sent outwards; wherein,,
the comb spectrum signal has the frequency of
Where Nf is the number of spectral lines,
the frequency of the transmitting-side rf signal is:
wherein f LSB For the frequency of the lower sideband signal at the transmitting end, f USB For the frequency of the sideband signal on the transmitting end, f LO Is the frequency of the local oscillation signal of the transmitting end.
In some of these embodiments, the receiving end of the reference antenna and the main antenna receives the transmitting end double sideband frequency signal, and then respectively couples with the receiving end local oscillator signal to generate a multi-frequency main signal and a reference signal, wherein,
the local oscillation signal frequency of the receiving end is
The frequency of the intermediate frequency signal received by the receiving ends of the reference antenna and the main antenna is
The specific method of the third step is as follows:
in some embodiments, the multi-frequency main-path signal and the reference-path signal are mixed to obtain an intermediate-frequency signal, and then the intermediate-frequency signal is accessed into a data acquisition and real-time FFT digital correlation system through an external analog input port to be converted into two paths of digital quantity data, the two paths of digital quantity data are subjected to Fourier transformation respectively, and then the two paths of digital quantity data after the Fourier transformation are multiplied to obtain FFT complex data.
The high-speed multi-frequency dual-channel data real-time cross-correlation implementation device comprises a signal transmitting end, a reference antenna, a main antenna and a data acquisition and real-time FFT digital correlation system, wherein the signal transmitting end is used for transmitting a double-sideband frequency signal with specific frequency, the reference antenna and the main antenna are used for receiving the double-sideband frequency signal transmitted by the signal transmitting end and modulating the double-sideband frequency signal of the transmitting end to generate a multi-frequency main channel signal and a reference channel signal, and the real-time FFT digital correlation system is used for carrying out FFT cross-correlation operation on the multi-frequency main channel signal and the reference channel signal and storing data.
In some embodiments, the signal transmitting end includes a comb spectrum intermediate frequency signal IF transmitting end, a transmitting end frequency synthesizer, a transmitting end integrated transmitting module, an isolator and a transmitting horn, wherein the comb spectrum signal sent by the comb spectrum intermediate frequency signal IF transmitting end and the local oscillator signal sent by the frequency synthesizer are coupled at the transmitting end integrated transmitting module to form a transmitting end double-sideband signal, and the transmitting end double-sideband signal is sent outwards from the transmitting horn after passing through the isolator. The reference antenna and the main antenna comprise a receiving horn, an integrated receiving module, a signal attenuation module, a low-noise amplifying module and a low-pass filtering module which are sequentially connected, wherein the receiving horn is used for receiving a transmitting-end double-sideband signal, the transmitting-end double-sideband signal and a receiving-end local oscillator signal are coupled by the integrated receiving module, and after being sequentially subjected to signal attenuation, low-noise amplification and low-pass filtering by the signal attenuation module, the low-noise amplifying module and the low-pass filtering module, a multi-frequency main signal and a reference signal are generated and are respectively input into the real-time FFT digital correlation system.
In some embodiments, the real-time multi-frequency dual-channel digital correlation system comprises multi-frequency signal acquisition and processing upper computer software, the processing software specifically comprises an FFT Fourier transform module, memories M1 and M2 opened by the software and an FIFO functional module, the multi-frequency signal acquisition and processing is used for converting multi-frequency main-channel signals and reference-channel signals to generate two-channel digital quantity data, the two-channel digital quantity data are respectively subjected to Fourier transform, then the two-channel digital quantity data after the Fourier transform are multiplied to obtain FFT complex data, and the upper computer processing software is used for storing the data calculated by the digital processing correlator.
The beneficial effects of the invention are as follows:
1. the invention adopts comb spectrum signals as a beacon source, can emit signals with a plurality of frequencies at one time, and generates a multi-frequency main path signal and a reference path signal after modulation of a reference antenna and a main antenna; and performing FFT cross correlation operation on the multi-frequency main path signal and the reference path signal to obtain FFT complex data, measuring by a near-field holographic measurement method according to the FFT complex data to obtain main antenna panel surface shape error data under multi-frequency scanning, and averaging the multi-frequency data to obtain an average value of the antenna panel surface shape.
2. The invention writes the cross-correlation operation into the memory M1 to obtain FFT complex data, writes the cross-correlation operation into the memory M2 to obtain FFT complex data when the accumulated times are larger than NumAcc, sets the memory read M2 as enabling when writing the data into the memory M1, namely reads the data of the memory M2 into the FIFO queue FIFO of the first-in first-out, otherwise sets the memory read M1 as enabling when writing the data into the memory M2, namely reads the data of the memory M1 into the FIFO, so that each moment has the data flow to the FIFO, and the ping-pong transmission mode of the data achieves the function of real-time FFT of a data pipeline, thereby improving the transmission speed of the data.
3. Unlike single frequency holographic measurement, the present invention uses comb spectrum multi-frequency signal as the emitting signal of holographic measurement in order to improve the influence of multipath effect on holographic measurement. Specifically, the generation mode of the multi-frequency transmitting signal is realized by setting the local oscillation signal, the spectral line number and the frequency interval, and the detail is shown in fig. 2. In this way, the signal transmitted by the horn end is a multi-frequency (fixed interval) regular radio frequency signal, and a multi-frequency signal receiving circuit (a main receiving circuit and a reference receiving circuit) is designed at the receiving end to demodulate the radio frequency signal. The use of such an integrated transmission module with double sidebands is an efficient way to achieve multi-frequency transmission.
4. The method and the device for realizing the real-time cross-correlation of the high-speed multi-frequency double-channel data mostly adopt modularized and parameterized design ideas. For example, signals of comb spectrum are generated by programming, frequency intervals, spectral line numbers and the like of the signals can be realized by programming, corresponding multi-frequency double-channel data acquisition and processing functions are developed based on a Labview software platform, sampling frequency of a system, frequency points of holographic measurement scanning and the like can be modified by setting on software, and the structural design is greatly convenient and meets various experimental parameter requirements of holographic measurement of a radio telescope antenna.
Drawings
FIG. 1 is a schematic diagram of near field holographic measurement;
FIG. 2 is a schematic diagram of the structure of a signal transmitting terminal;
fig. 3 is a schematic structural diagram of the reference antenna and the receiving end of the main antenna;
FIG. 4 is a schematic diagram of a two-channel multi-frequency simultaneous cross-correlation FFT operation;
FIG. 5 is a schematic diagram of FFT and cross-correlation calculations using a PXIe-5785 transceiver module;
FIG. 6 is a cross-correlation high-speed data acquisition flow chart;
fig. 7 is a flow chart of multi-frequency simultaneous data processing.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. 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.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Examples:
the invention aims to realize the dual-channel high-data high-speed real-time multi-frequency FFT cross-correlation operation. The method mainly comprises the functions of double-channel data acquisition, multi-frequency FFT real-time correlation operation, data splicing and extraction, large-rate acquisition data uploading and the like. Can be divided into multi-frequency simultaneous transmitting parts from the realized function; a dual-channel multi-frequency simultaneous receiving section; the two-channel multi-frequency simultaneous cross-correlation FFT operation part and the two-channel multi-frequency simultaneous cross-correlation high-speed data acquisition are four major parts.
(1) Multi-frequency simultaneous transmission
The system block diagram of the signal transmitting end is as shown in fig. 2:
and a comb spectrum signal is adopted as a beacon source at a signal transmitting end. The frequency range of the comb spectrum signal is 6.25 MHz-1.2 GHz (frequency interval 6.25 MHz). The comb spectrum signal is generated by Matlab programming, and the program operation generates a data text (txt format). And Labview programming is adopted, comb spectrum signals are loaded to the intermediate frequency IF transceiver module and are sent outwards through the analog output port, the fixed sampling frequency of the intermediate frequency IF transceiver module is 3.2GHz, and the data length of the intermediate frequency IF transceiver module is exactly one whole period of the comb spectrum frequency interval.
The frequency interval Δf of the comb-like spectrum signal is set to be an integer multiple of the FFT spectrum interval, i.e., Δf=nf s N, N is a positive integer, N is the FFT length.
The local oscillation frequency of the signal transmitting end is 90GHz, and the signal transmitting end is obtained by 8 times of frequency. The comb spectrum signal and the transmitting end local oscillator signal generate a transmitting end double-sideband frequency signal under the action of the transmitting end integrated transmitting module. The upper sideband has a frequency of 90ghz+m 6.25MHz (m=1, 2, 3..192) for a total of 192 spectral lines and the lower sideband has a frequency of 90GHz-m 6.25MHz. The double-sideband signal is transmitted outwards through the isolator and the attenuator by the transmitting loudspeaker and is received by the primary receiver and the reference path receiver on the panel of the radio telescope.
(2) Dual-channel multi-frequency simultaneous reception
The dual-channel multi-frequency simultaneous receiving schematic block diagram is shown in fig. 3. Because the transmitting beacon source adopts double sideband signal modulation, in order to ensure that signals obtained by the front section of the receiver of the double side signal do not overlap, the local oscillation frequency of the receiver and the local oscillation frequency of the transmitting source need to be calculated, and the method comprises the following steps:
the frequency of the transmitted baseband signal is
The comb spectrum signal has the frequency of
Where Nf is the number of spectral lines,
the frequency of the outgoing transmitting-side double sideband signal is:
wherein f LSB For the frequency of the lower sideband signal at the transmitting end, f USB For the frequency of the sideband signal on the transmitting end, f LO Is the frequency of the local oscillation signal of the transmitting end.
The receiving end of the reference antenna and the main antenna receives the double sideband frequency signals of the transmitting end and then respectively couples with the local oscillation signals of the receiving end to generate a multi-frequency main signal and a reference signal,
the local oscillation signal frequency of the receiving end is
Receiving the intermediate frequency signal at a frequency of
The corresponding relation between the transmitting frequency and the receiving intermediate frequency is shown in the table
In actual measurement, the local oscillation frequency of the transmitting end is 90GHz, the Δf frequency interval is 6.25MHz, and the spectral line number n is 192. The frequency range of the transmitting end (transmitting to the loudspeaker) is 88.8 GHz-91.2 GHz according to the parameters, and the input requirements of the double-sideband transmission of the transmitting module are met.
After receiving the transmitting end double-sideband frequency signals, the receiving ends of the reference antenna and the main antenna respectively attenuate the transmitting end double-sideband frequency signals, amplify the signals with low noise, filter the signals with low pass and the like to generate a multi-frequency main path signal and a reference path signal of 1.5625MHz+0.5 Deltaf, the multi-frequency main path signal and the reference path signal are mixed to obtain intermediate frequency signals, the intermediate frequency signals are accessed into a data acquisition and real-time FFT digital correlation system through external analog input ports to be converted into two paths of digital data, the two paths of digital data are subjected to Fourier transformation respectively, and then the two paths of digital data after the Fourier transformation are multiplied to obtain FFT complex data.
(3) Dual-channel multi-frequency simultaneous cross-correlation FFT operation
The main controller of the FFT digital correlation system reads two paths of analog quantity data from a Socket port, converts the two paths of 12-bit analog digital signals to generate two paths of digital quantity data, performs Fourier transformation on the two paths of digital quantity data, and then performs Fourier transformationAnd multiplying the two paths of digital quantity data after the fourier transformation to obtain FFT complex data. The correlation machine is a key link of signal processing, and the mathematical principle of the correlation machine is a multiplication process of two complex numbers. I.e. fourier transform is performed first and then multiplication is performed. For two related signals, two signals need to be subjected to FFT transformation respectively, and the simplest method for solving the problem is to use two independent FFT kernels. From the mathematical theorem, it is known that the time domain convolution corresponds to frequency domain conjugate multiplication, and the result of the cross correlation of the above signals is Y is the time domain convolution, Y S Is a main path frequency domain signal, Y R * Is the conjugate of the reference path frequency domain signal. This has the advantage that the processing avoids the convolution process, and the corresponding multiplication is performed after the frequency domain signal is obtained, so that a lot of resources and time can be saved.
For example, two complex numbers x=xr+ jXi, y=yr+ jYi, where XrYr is the real part of XY and XiYi is the imaginary part of XY, respectively. Their cross-correlation operation is
Z=xy=x= (xryr+xiyi) +j (XiYr-XrYi) =zr+ jZi formula (5)
Where Y is the conjugate of Y, zr=xryr+xiyi, zi=xiyr-XrYi
According to the requirements, multi-frequency simultaneous cross-correlation lower computer software is developed on a data acquisition and real-time FFT digital correlation system platform, the development environment is Labview, and a platform on hardware is a PXIe-5785 intermediate frequency transceiver module based on an embedded FPGA.
The PXIe-5785 transceiver combines analog I/O with a user programmable FPGA. Can work in a double-channel mode with the speed reaching 3.2GS/s, and can also work in a single-channel staggered mode with the speed reaching 6.4GS/s. The PXIe-5785 transceiver adopts an FPGA and provides LabVIEW programming options, and can realize custom algorithm and real-time signal processing.
As shown in fig. 5, the main signal path and the reference signal path input signals through a Socket port of the PXIe-5785 transceiver module. When FFT operation is carried out, two FFT IP cores provided by Labview and specially used for calculating fast Fourier transform are adopted, FFT conversion functions of a main path and a reference path are respectively realized, a time domain signal is converted into a frequency domain signal, and real part and imaginary part frequency spectrum information of an input signal is obtained by calculation. In the process of calculating the cross-correlation Zr, a self-contained operation module such as multiplication, addition, subtraction and the like is also adopted to realize the expression (5). Compiling after the design of the lower computer is finished, and loading the Labview upper computer by generating lvbitx.
(4) Dual-channel multi-frequency simultaneous cross-correlation high-speed data acquisition
The two-channel multi-frequency simultaneous cross-correlation high-speed data acquisition upper computer program is written by using a Labview environment and using a graphical control. In order to obtain the complex data of the cross correlation in real time, the following processes are mainly adopted in the upper computer graphic programming, see fig. 6.
When the received signal is FFT transformed, the sampling frequency is fs, the sampling point number is Ns, and if the integration time is T, the calculation formula of the number of frames (accumulation times) NumAcc is
In this item, the sampling frequency fs=3.2 GHz, and the sampling point number ns=4096, and the FFT resolution 0.78125MHz. In general, if the integration time is set to 50ms, the number of times that accumulation is required for a certain reception frequency is 39062 times. When FFT is started, whether the accumulated times reach 39062 is judged first, and if the accumulated times do not reach 39062, the program writes real part and imaginary part data after cross-correlation into a vi-defined memory M1 defined by Labview. When the number of times is larger than the accumulated number of times, the cross-correlation data is written into the defined memory M2. When writing data to M1, the read M2 memory is set to enable, i.e., the data of M2 can be read into FIFO (first in first out queue). Otherwise, when writing data to M2, setting the read M1 as the memory, i.e. reading the data of M1 into the FIFO. Therefore, each moment is formed by flowing data into the FIFO, so that a ping-pong transmission mode of the data is formed, the function of real-time FFT of a data pipeline is achieved, and the transmission speed of the data is improved. And finally, uniformly uploading the data in the FIFO to a host end by a host channel. The main flow of the multi-frequency simultaneous data processing at the program upper computer end is as shown in fig. 7:
the number of times that accumulation is required is calculated based on the sampling frequency, the number of sampling points and the integration time (set in advance in the software) parameters. And dividing the accumulated complex number of the cross-correlation by the accumulated number of times to obtain the average real part and imaginary part values of the complex number of the cross-correlation. Then extracting the complex number of the multifrequency, wherein the extracting interval is related to the received upper and lower sideband frequencies and the resolution of FFT, and the specific extracting method is as follows:
in the system, the sampling frequency of the FFT is 3.2GHz, the sampling point number is 4096 points, and the interval frequency of the FFT is 0.78125MHz. I.e. the spectrum of the FFT is 0.78125M x n, an integer multiple of 0.78125M.
On the other hand, the frequency of the receiver is 1.5625mhz+0.5×6.25mhz (frequency interval), i.e. 1.5625mhz+3.125mhz×n.
Comparing the two frequency sequences of 0.78125MHz x n and 1.5625MHz x n with the two frequency sequences of 1.5625MHz x n, if the frequency sequence of 1.5625MHz x n and 3.125MHz x n is obtained, the frequency point of the receiver is obtained by extracting the 0.7825 MHz x n sequence from 1.5625MHz once every four frequency points, namely, four-one operation is performed on the 0.7825 MHz x n sequence, and the frequency point of the receiver can be obtained.
And then performing operation on the cross-correlation complex numbers of each frequency point after four-extraction operation, and storing and processing to obtain the cross-correlation complex number data to be processed under each spectral line number.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the invention without departing from the principles thereof are intended to be within the scope of the invention as set forth in the following claims.
Claims (10)
1. The method for realizing real-time cross-correlation of high-speed multi-frequency dual-channel data is characterized by comprising the following steps of: the method comprises the following steps:
step one, a signal transmitting end adopts a comb spectrum signal as a beacon source, and the comb spectrum signal is modulated by a double sideband signal of the transmitting end and then is sent out;
step two, after receiving the transmitting end double sideband frequency signals by the receiving ends of the reference antenna and the main antenna, modulating the transmitting end double sideband frequency signals by the respective receiving end double sideband signals respectively to generate a multi-frequency main path signal and a reference path signal;
step three, mixing the multi-frequency main path signal and the reference path signal to obtain intermediate frequency signals, converting the two paths of intermediate frequency signals to generate digital quantity data, performing FFT cross correlation operation to obtain FFT complex data,
step four, carrying out high-speed data acquisition on the cross-correlation operation:
assuming that the FFT sampling frequency is fs, the sampling point number is Ns, and if the integration time is T, the calculation formula of the number of frames NumAcc is
In order to increase the transmission speed of the cross-correlation data to the upper computer, two memories M1 and M2 are opened up in the Labview software programming upper computer transmission program, when the FFT cross-correlation operation of the third step is started, whether the accumulated times of FFT sampling reach NumAcc is judged first, if not, the FFT complex data is obtained by writing the cross-correlation operation into the memory M1, when the accumulated times are larger than NumAcc, the FFT complex data is obtained by writing the cross-correlation operation into the memory M2, when the data is written into the memory M1, the memory M2 is set as enabling, namely the data of the M2 is read into a first-in first-out queue FIFO, otherwise, when the data is written into the memory M2, the memory M1 is set as enabling, namely the data of the M1 is read into the FIFO, so that the data flows to the FIFO at each moment, and the ping-pong transmission mode of the data is formed,
and fifthly, uploading data acquisition in the FIFO.
2. The method for realizing real-time cross-correlation of high-speed multi-frequency and dual-channel data according to claim 1, which is characterized in that: in the first step, the comb spectrum signal is generated by Matlab programming, labview programming is adopted, the comb spectrum signal is loaded to an intermediate frequency IF transceiver module to be sent outwards through an analog output port, the fixed sampling frequency of the intermediate frequency IF transceiver module is 3.2GHz, and the data length of the fixed sampling frequency is exactly one whole period of the comb spectrum frequency interval.
3. The method for realizing real-time cross-correlation of high-speed multi-frequency and dual-channel data according to claim 1, which is characterized in that: the frequency interval Δf of the comb-like spectrum signal is set to be an integer multiple of the FFT spectrum interval, i.e., Δf=nf s N, N is a positive integer, N is the FFT length.
4. The method for realizing real-time cross-correlation of high-speed multi-frequency and dual-channel data according to claim 1, which is characterized in that: the comb spectrum signal and the transmitting end local oscillator signal generate a transmitting end double-sideband signal consisting of a transmitting end upper sideband signal and a transmitting end lower sideband signal, and the transmitting end double-sideband signal is sent outwards; wherein,,
the comb spectrum signal has the frequency of
Where Nf is the number of spectral lines,
the frequency of the outgoing transmitting-side double sideband signal is:
wherein f LSB For the frequency of the lower sideband signal at the transmitting end, f USB For the frequency of the sideband signal on the transmitting end, f LO Is the frequency of the local oscillation signal of the transmitting end.
5. The method for realizing real-time cross-correlation of high-speed multi-frequency and dual-channel data according to claim 1, which is characterized in that: the receiving end of the reference antenna and the main antenna receives the double sideband frequency signals of the transmitting end and then respectively couples with the local oscillation signals of the receiving end to generate a multi-frequency main signal and a reference signal,
the local oscillation signal frequency of the receiving end is
The frequency of the intermediate frequency signal received by the receiving ends of the reference antenna and the main antenna is
6. The method for realizing real-time cross-correlation of high-speed multi-frequency and dual-channel data according to claim 1, which is characterized in that: the specific method of the third step is as follows:
the multi-frequency main channel signal and the reference channel signal are mixed to obtain an intermediate frequency signal, the intermediate frequency signal is accessed into a data acquisition and real-time FFT digital correlation system through an external analog input port to be converted into two paths of digital quantity data, the two paths of digital quantity data are subjected to Fourier transformation respectively, and then the two paths of digital quantity data after the Fourier transformation are multiplied to obtain FFT complex data.
7. High-speed multifrequency binary channels data real-time cross-correlation realization device, characterized by: the system comprises a signal transmitting end, a reference antenna, a main antenna and a data acquisition and real-time FFT digital correlation system, wherein the signal transmitting end is used for transmitting a transmitting end double-sideband frequency signal with specific frequency, the reference antenna and the main antenna are used for receiving the double-sideband frequency signal transmitted by the signal transmitting end, modulating the transmitting end double-sideband frequency signal to generate a multi-frequency main path signal and a reference path signal, and the real-time FFT digital correlation system is used for carrying out FFT cross-correlation operation on the multi-frequency main path signal and the reference path signal and storing data.
8. The high-speed multi-frequency and dual-channel data real-time cross-correlation realizing device according to claim 7, wherein the device is characterized in that: the signal transmitting end comprises a comb spectrum intermediate frequency signal IF transmitting end, a transmitting end frequency synthesizer, a transmitting end integrated transmitting module, an isolator and a transmitting loudspeaker, wherein a comb spectrum signal sent by the comb spectrum intermediate frequency signal IF transmitting end and a transmitting end local oscillator signal sent by the transmitting end frequency synthesizer are coupled at the transmitting end integrated transmitting module, and formed transmitting end double-sideband signals are sent outwards from the transmitting loudspeaker after passing through the isolator.
9. The high-speed multi-frequency and dual-channel data real-time cross-correlation realizing device according to claim 7, wherein the device is characterized in that: the reference antenna and the main antenna comprise a receiving horn, an integrated receiving module, a signal attenuation module, a low-noise amplifying module and a low-pass filtering module which are sequentially connected, wherein the receiving horn is used for receiving a transmitting-end double-sideband signal, the transmitting-end double-sideband signal and a receiving-end local oscillator signal are coupled by the integrated receiving module, and after being sequentially subjected to signal attenuation, low-noise amplification and low-pass filtering by the signal attenuation module, the low-noise amplifying module and the low-pass filtering module, a multi-frequency main signal and a reference signal are generated and are respectively input into the real-time FFT digital correlation system.
10. The high-speed multi-frequency and dual-channel data real-time cross-correlation realizing device according to claim 7, wherein the device is characterized in that: the real-time multi-frequency dual-channel digital correlation system comprises multi-frequency signal acquisition and processing upper computer software, wherein the multi-frequency signal acquisition and processing upper computer software specifically comprises an FFT Fourier transform module, memories M1 and M2 opened by the software and an FIFO functional module, the multi-frequency signal acquisition and processing upper computer software is used for transforming multi-frequency main-channel signals and reference-channel signals to generate two-channel digital quantity data, respectively performing Fourier transform on the two-channel digital quantity data, multiplying the two-channel digital quantity data after the Fourier transform to obtain FFT complex data, and storing the data calculated by a digital processing correlator.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102788909A (en) * | 2011-05-18 | 2012-11-21 | 中国科学院上海天文台 | Method for measuring surface accuracy of antenna by adopting holographic method |
| CN103884922A (en) * | 2014-03-26 | 2014-06-25 | 中国科学院紫金山天文台 | Measuring device and method for Terahertz vector field shape of single receiver |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN102788909A (en) * | 2011-05-18 | 2012-11-21 | 中国科学院上海天文台 | Method for measuring surface accuracy of antenna by adopting holographic method |
| CN103884922A (en) * | 2014-03-26 | 2014-06-25 | 中国科学院紫金山天文台 | Measuring device and method for Terahertz vector field shape of single receiver |
Non-Patent Citations (1)
| Title |
|---|
| 基于PCI9820和GP2015的GPS信号采集与频谱分析;纪元法;孙希延;施浒立;王晓岚;;现代电子技术(第21期);全文 * |
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