CN114563769A - Method and device for measuring phase nonlinearity of digital phased array receiving channel - Google Patents
Method and device for measuring phase nonlinearity of digital phased array receiving channel Download PDFInfo
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Abstract
The invention discloses a method and a device for measuring phase nonlinearity of a digital phased array receiving channel, which belong to the technical field of input signal testing, wherein the method comprises the steps of generating a baseband linear frequency modulation signal a, correcting based on a correction signal a, and generating a broadband radio frequency linear frequency modulation signal b and a delay linear frequency modulation signal d; inputting the wide signal b into a digital phased array receiving channel to obtain multi-channel baseband I/Q data c; performing cross-correlation operation on the multi-channel baseband I/Q data c and the signal d to obtain related peak data e; carrying out peak value searching and interpolation operation on the related peak data e to obtain the delay f at the peak value; generating a synchronous linear frequency modulation signal g based on the delay f and the integer cosy delay; and calculating the phase nonlinearity h of the digital phased array receiving channel based on the signal g and the multi-path baseband I/Q data c. The algorithm of the invention has the advantages of low software resource overhead, high measurement speed and no need of auxiliary narrow pulse generation equipment and ultrahigh-speed data acquisition equipment.
Description
Technical Field
The invention relates to the technical field of signal testing, in particular to a method and a device for measuring phase nonlinearity of a digital phased array receiving channel.
Background
Phase nonlinearity is one of the important performance indicators for digital phased array receive channels. The ideal transmission system has no phase nonlinear distortion, however, because of the influence of the factors such as the filter, the mixer, the amplifier and the impedance matching network in the receiving link, the phase and the frequency in the frequency band do not have a strict linear relationship, and the performance is particularly obvious in a broadband system. The phase nonlinear index directly determines the distortion degree of a signal passing through a transmission system, influences the pulse pressure side lobe performance of a radar system or the intersymbol interference performance of a communication system, influences the beam forming performance of a phased array system, and has important significance on the performance index of the whole digital phased array system.
The traditional phase nonlinearity measurement method is to directly measure a two-port tested analog network by using a test scheme based on a vector network analyzer, for example, a double-phase reference nonlinearity vector network analyzer measurement method and device disclosed in the patent application No. 201710943353.9. However, this method has the following limitations: first, the phase nonlinearity of analog-to-digital hybrid systems like digital phased array receive channels (from antenna to ADC baseband data) cannot be measured directly; secondly, it is difficult to directly measure the phase nonlinearity of the frequency conversion system; finally, the test efficiency is low, and the phase nonlinearity of a large digital phased array with thousands of channels cannot be measured simultaneously.
The invention patent application with application number 201610702093.1 provides a digital domain phase nonlinear measurement method, which obtains phase nonlinear distortion by deconvolution processing or full-phase FFT conversion algorithm based on a narrow pulse signal with specific time width and repetition period. The measurement method has strict requirements on the width of a test pulse, particularly, the measurement method needs to generate an extremely narrow pulse when being applied in a large bandwidth, and the requirement on hardware is high. Meanwhile, the effective sampling window of the measuring method is the narrow pulse width, in order to obtain enough data analysis samples, the system sampling interval needs to be far smaller than the narrow pulse width, ultra-high-speed data acquisition equipment needs to be adopted in broadband application, and hardware cost burden is additionally increased.
In view of the above situation, it is necessary to develop a fast and simple phase nonlinear measurement method in the digital domain based on the inherent calibration network of the system for a large-scale frequency conversion and analog-to-digital hybrid system such as a digital phased array receiving channel without adding additional test equipment, thereby reducing the hardware and software costs of the test system and the total test time. Therefore, a method and a device for measuring the phase nonlinearity of a digital phased array receiving channel are provided.
Disclosure of Invention
The technical problem to be solved by the invention is how to realize the measurement of the phase nonlinearity in the digital domain without adding extra test equipment.
The invention solves the technical problems through the following technical means:
in one aspect, the present invention provides a method for measuring phase nonlinearity of a digital phased array receiving channel, where the method includes the following steps:
generating a baseband linear frequency modulation signal a, and correcting the baseband linear frequency modulation signal a based on a correction source to generate a broadband radio frequency linear frequency modulation signal b;
inputting the broadband radio frequency linear frequency modulation signal b into a digital phased array receiving channel to obtain multi-channel baseband I/Q data c;
carrying out integral-multiple time delay on the baseband linear frequency modulation signal a to obtain a time-delay linear frequency modulation signal d;
performing cross-correlation operation on the multi-channel baseband I/Q data c and the delayed linear frequency modulation signal d to obtain related peak data e;
performing peak value searching and interpolation operation on the related peak data e to obtain the delay f at the peak value;
generating a synchronous linear frequency modulation signal g based on the delay f and the integer cosy delay;
and calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c.
The invention processes the broadband test chirp signals based on the self-contained correction source and the receiving channel of the digital phased array system, simultaneously measures the phase nonlinearity of all channels by utilizing the precise and synchronous broadband chirp signals, has small algorithm software resource overhead and high measurement speed, and does not need auxiliary narrow pulse generation equipment and ultrahigh speed data acquisition equipment.
Optionally, a bandwidth of the baseband chirp signal a is the same as a channel bandwidth of the digital phased array receiving channel, and a time-width bandwidth product of the baseband chirp signal a is not less than (360/δ)2/10SNRWhere δ (in degrees) is the phase non-linearity measurement error and SNR (in dB) is the signal-to-noise ratio of the baseband chirp signal a.
Optionally, the correcting the baseband chirp signal a based on the correction source to generate a wideband radio frequency chirp signal b includes:
and a correction source generation module is adopted to sequentially perform digital-to-analog conversion, up-conversion, filtering and signal amplification on the baseband linear frequency modulation signal a, so as to generate the broadband radio frequency linear frequency modulation signal b, wherein the correction source is a correction source obtained after inherent phase nonlinear self-calibration.
Optionally, the inputting the wideband radio frequency chirp signal b into a digital phased array receiving channel to obtain multiple paths of baseband I/Q data c includes:
and the digital phased array receiving channel sequentially performs down-conversion, filtering, signal amplification and digital preprocessing on the broadband radio frequency linear frequency modulation signal b to obtain the multi-channel baseband I/Q data c.
Optionally, the integer multiple delay is equal to a sum of a delay of the correction source generation module and a delay of the digital phased array receiving channel.
Optionally, the performing a cross-correlation operation on the multiple paths of baseband I/Q data c and the delayed chirp signal d to obtain correlation peak data e includes:
performing time domain turnover on the time-delay linear frequency modulation signal d;
performing conjugate operation on the multi-path baseband I/Q data c;
and performing convolution operation on the time-domain reversed time-delay linear frequency modulation signal and the multi-channel baseband I/Q data after conjugation, and outputting the related peak data e.
Optionally, the performing peak search and interpolation operation on the correlation peak data e to obtain the delay f at the peak value includes:
performing peak value searching operation on the related peak data e to obtain data samples near a peak value;
and calculating the delay f at the peak value by adopting a high-order polynomial interpolation algorithm based on the data samples near the peak value.
Optionally, the generation delay of the synchronous chirp signal g is a sum of the delay f and the integer coslay.
Optionally, the calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multiple paths of baseband I/Q data c includes:
respectively carrying out phase calculation on the synchronous linear frequency modulation signal g and the multi-channel baseband I/Q data c to obtain phase calculation results;
performing difference calculation on the phase calculation result to obtain a difference result;
and performing deskew calculation on the difference result, removing a first-order linear component and a direct-current component, and outputting the phase nonlinearity h.
In addition, the invention also provides a device for measuring the phase nonlinearity of the receiving channel of the digital phased array, which comprises:
the test chirp signal generation module is used for generating a baseband chirp signal a and inputting the baseband chirp signal a to the correction source generation module and the integral multiple delay module;
the correction source generation module is used for correcting the baseband linear frequency modulation signal a, outputting a broadband radio frequency linear frequency modulation signal b and feeding the broadband radio frequency linear frequency modulation signal b into a digital phased array receiving channel through a coupling network;
the digital phased array receiving channel is used for processing the broadband radio frequency linear frequency modulation signal b to form multi-channel baseband I/Q data c and inputting the multi-channel baseband I/Q data c to the correlator module;
the integral multiple time delay module is used for carrying out integral multiple clock cycle time delay on the baseband linear frequency modulation signal a to obtain a time delay linear frequency modulation signal d and inputting the time delay linear frequency modulation signal d to the correlator module;
the correlator module is used for performing cross-correlation operation on the delayed linear frequency modulation signal d and the multi-channel baseband I/Q data c to obtain related peak data e and inputting the related peak data e to the delay calculation module;
the delay calculation module is used for performing peak value searching and interpolation operation on the related peak data e to obtain a delay f at a peak value and inputting the delay f to the synchronous linear frequency modulation signal generation module;
the synchronous linear frequency modulation signal generating module is used for generating a synchronous linear frequency modulation signal g to the phase nonlinear computing module based on the delay f and the integral multiple delay;
and the phase nonlinearity calculation module is used for calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c.
Optionally, the bandwidth of the baseband chirp signal a is the same as the channel bandwidth of the digital phased array receiving channel, and the time-width bandwidth product of the baseband chirp signal a is not less than (360/δ)2/10SNRWhere δ is the phase non-linearity measurement error and SNR is the signal-to-noise ratio of the baseband chirp signal a.
Optionally, the correction source generating module is specifically configured to:
and sequentially performing digital-to-analog conversion, up-conversion, filtering and signal amplification on the baseband linear frequency modulation signal a to generate a broadband radio frequency linear frequency modulation signal b.
Optionally, the integer multiple delay is equal to a sum of a delay of the correction source generation module and a delay of the digital phased array receiving channel.
Optionally, the correlator module comprises:
the time domain overturning unit is used for carrying out time domain overturning on the time delay linear frequency modulation signal d and inputting the overturned signal into the convolution unit;
a conjugate taking unit, configured to perform conjugate taking operation on the multi-path baseband I/Q data c, and input a signal after conjugate taking to the convolution unit;
and the convolution unit is used for performing convolution operation on the time-domain reversed time-delay linear frequency modulation signal and the conjugated multi-channel baseband I/Q data and outputting the related peak data e.
Optionally, the phase nonlinearity calculation module includes:
the first phase calculation unit is used for carrying out phase calculation on the synchronous linear frequency modulation signal g to obtain a first phase calculation result and inputting the first phase calculation result to the difference value calculation unit;
the second phase calculation unit is used for carrying out phase calculation on the multi-channel baseband I/Q data c to obtain a second phase calculation result and inputting the second phase calculation result to the difference calculation unit;
the difference calculation unit is used for performing difference operation on the first phase calculation result and the second phase calculation result and inputting the difference result to the deskew calculation unit;
and the deskew calculation unit is used for carrying out deskew operation on the difference result, removing a first-order linear component and a direct-current component and outputting the phase nonlinearity h.
In addition, the invention also provides a device for measuring the phase nonlinearity of the digital phased array receiving channel, which comprises a memory and a processor; wherein the processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory for implementing the method as described above.
Furthermore, the present invention also proposes a computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the method as described above.
The invention has the advantages that:
(1) the invention processes the broadband test chirp signals based on the correction source and the receiving channel of the digital phased array system, simultaneously measures the phase nonlinearity of all channels by utilizing the precise and synchronous broadband chirp signals, has low algorithm software resource overhead and high measuring speed, and does not need auxiliary narrow pulse generating equipment and ultrahigh-speed data acquisition equipment.
(2) The time width of the broadband test linear frequency modulation signal is far larger than the pulse width of the traditional single pulse method, the data sampling rate is far lower than the sampling rate of the traditional single pulse method, and the hardware complexity and the cost are greatly reduced.
(3) The invention comprehensively adopts the methods of phase difference finding and phase deskew, calculates the phase nonlinearity of the digital phased array receiving channel, and has low algorithm complexity and high measurement precision of the phase nonlinearity.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a method for measuring phase nonlinearity of a digital phased array receiving channel according to the present invention;
FIG. 2 is a flow chart of correlation peak data calculation in the present invention;
FIG. 3 is a flow chart of phase nonlinearity calculation according to the present invention;
FIG. 4 is a block diagram of a device for measuring phase nonlinearity of a digital phased array receiving channel according to the present invention;
FIG. 5 is a block diagram of a correlator module of the present invention;
FIG. 6 is a block diagram of a phase nonlinearity calculation module according to the present invention;
fig. 7 is a block diagram of a measuring apparatus for phase nonlinearity of a digital phased array receiving channel according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for measuring phase nonlinearity of a digital phased array receiving channel according to the present invention, where the method includes the following steps:
s101, generating a baseband linear frequency modulation signal a, correcting the baseband linear frequency modulation signal a based on a correction source, and generating a broadband radio frequency linear frequency modulation signal b;
illustratively, the baseband chirp signal a may be:
wherein S isa(n) is a baseband chirp signal a; k is the digital modulation slope, and K is BW/tau/fs 2BW is the bandwidth of the baseband chirp signal a, tau is the time width of the baseband chirp signal a, fsIs the sampling rate; n is [ -N/2, N/2]N is the number of valid sampling points of the baseband chirp signal a, N ═ τ fs(ii) a j is
In this embodiment, K is 1.25, the bandwidth of the baseband chirp signal a is 1GHz, the time width is 50us, the sampling rate is 4Gsps, and N is 200000.
S102, inputting the broadband radio frequency linear frequency modulation signal b into a digital phased array receiving channel to obtain multi-channel baseband I/Q data c;
in this embodiment, the wideband rf chirp signal b is fed to the digital phased array receive channel via a feed network.
Illustratively, the wideband radio frequency chirp signal b may be:
wherein S isc(n) is multi-channel baseband I/Q data c; t is tDDelaying the integral multiple of the multi-channel baseband I/Q data c; t is tF0Delaying for a decimal time of the multi-path baseband I/Q data c;
is the phase nonlinear data to be solved.
S103, carrying out integral multiple time delay on the baseband linear frequency modulation signal a to obtain a time-delay linear frequency modulation signal d;
illustratively, the time-delayed chirp d may be:
wherein, the delay value t of integral time delayDEqual to the sum of the delay of the calibration source and the delay of the digital phased array receiving channel, so that the delayed chirp signal d is roughly synchronized with the multi-channel baseband I/Q data c in time.
S104, performing cross-correlation operation on the multi-channel baseband I/Q data c and the delayed linear frequency modulation signal d to obtain related peak data e;
s105, performing peak value searching and interpolation operation on the related peak data e to obtain a delay f at a peak value;
s106, generating a synchronous linear frequency modulation signal g based on the delay f and the integer cosy delay;
and S107, calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-channel baseband I/Q data c.
The embodiment of the invention processes the broadband test chirp signals based on the correction source and the receiving channel of the digital phased array system, simultaneously measures the phase nonlinearity of all channels by utilizing the precise synchronous broadband chirp signals, has low algorithm software resource overhead and high measurement speed, and does not need auxiliary narrow pulse generation equipment and ultrahigh speed data acquisition equipment.
In one embodiment, the bandwidth of the baseband chirp signal a is the same as the channel bandwidth of the digital phased array receive channel, and the time-width bandwidth product of the baseband chirp signal a is not less than (360/δ)2/10SNRWhere δ (in degrees) is the phase non-linearity measurement error and SNR (in dB) is the signal-to-noise ratio of the baseband chirp signal a.
In this embodiment, the phase nonlinearity measurement error is required to be less than 1 °, and the signal-to-noise ratio of the baseband chirp signal a is 10dB, so the time-bandwidth product is not less than 12960, and actually 1GHz × 50us is 50000.
It should be noted that the time width of the baseband chirp signal a is much larger than the pulse width of the conventional single pulse method, and the data sampling rate is much lower than that of the conventional single pulse method, thereby greatly reducing the hardware complexity and cost.
In an embodiment, the step S101 specifically includes:
and after digital-to-analog conversion, up-conversion, filtering and signal amplification processing are sequentially carried out on the baseband linear frequency modulation signal a by adopting the correction source, the broadband radio frequency linear frequency modulation signal b is generated, and the correction source is a correction source after inherent phase nonlinear self-calibration.
It should be noted that the inherent phase nonlinearity of the correction source can be self-calibrated by using oscilloscope data acquisition, predistortion filter coefficient calculation and digital predistortion compensation methods.
In an embodiment, the step S102 specifically includes:
and the digital phased array receiving channel sequentially performs down-conversion, filtering, signal amplification and digital preprocessing on the broadband radio frequency linear frequency modulation signal b to obtain the multi-channel baseband I/Q data c.
In an embodiment, referring to fig. 2, the step S104 includes the following steps:
s1041, performing time domain turnover on the time-delay linear frequency modulation signal d;
s1042, performing conjugate operation on the multi-path baseband I/Q data c;
and S1043, performing convolution operation on the time-domain reversed time-delay linear frequency modulation signal and the multi-channel baseband I/Q data after conjugation, and outputting the related peak data e.
Exemplarily, since the correlation peak after convolution operation appears in the middle region of the data, only the output correlation peak result of the middle region needs to be calculated, and all correlation peak data do not need to be calculated in the whole process, thereby greatly reducing the operation amount; in one embodiment, only the middle 20 consecutive data are computed, sufficient to cover a complete correlation peak.
In one embodiment, the step S105 includes the following steps:
s1051, carrying out peak value searching operation on the related peak data e to obtain data samples near the peak value;
and S1052, calculating the time delay f at the peak value by adopting a high-order polynomial interpolation algorithm based on the data samples near the peak value.
Illustratively, three point amplitudes at the peak are taken and are respectively A0、A1And A2The delay values corresponding to these three points are respectively t0、t1And t2Then the value of the precise delay f is:
wherein, tF1Is the exact delay f.
In one embodiment, in the step S106, the generation delay of the synchronous chirp signal g is a sum of the delay f and the integer coslay.
Illustratively, the synchronous chirp signal g may be:
in an embodiment, referring to fig. 3, the step S107 includes the following steps:
s1071, respectively carrying out phase calculation on the synchronous linear frequency modulation signal g and the multi-channel baseband I/Q data c to obtain phase calculation results;
illustratively, the phase calculation employs an arctangent calculation method based on coordinate rotation digital computation (CORDIC).
S1072, carrying out difference calculation on the phase calculation result to obtain a difference result;
for example, the phase difference operation result of the synchronous chirp signal g and the multiple baseband I/Q data c may be:
wherein,
is the phase difference operation result.
S1073, the difference result is subjected to deskew calculation, a first-order linear component and a direct-current component are removed, and the phase nonlinearity h is output.
Illustratively, a least squares linear fitting algorithm is used to obtain
The slope of (d) is 2 pi K (t)F1-tF0) To obtain
Is-2 pi K (t)F1-tF0)*(tD+(tF1+tF0)/2)；
Get rid of
The phase nonlinearity h obtained by the slope and the bias term in (1) is:
it should be noted that, in this embodiment, a phase difference and phase deskew method is comprehensively adopted, so that the algorithm complexity is low, and the measurement accuracy of phase nonlinearity is high.
Referring to fig. 4, fig. 4 is a schematic flow chart of an embodiment of a device for measuring phase nonlinearity of a digital phased array receiving channel according to the present invention, the device including:
the test chirp signal generation module 201 is configured to generate a baseband chirp signal a and input the baseband chirp signal a to the calibration source generation module 202 and the integer-times delay module 204;
the calibration source generating module 202 is configured to calibrate the baseband chirp signal a, output a wideband radio frequency chirp signal b, and feed the wideband radio frequency chirp signal b into the digital phased array receiving channel 203 through a coupling network;
the digital phased array receiving channel 203 is configured to process the wideband radio frequency chirp signal b to form a plurality of paths of baseband I/Q data c, and input the plurality of paths of baseband I/Q data c to the correlator module 205;
the integral multiple delay module 204 is configured to perform integral multiple clock cycle delay on the baseband chirp signal a to obtain a delayed chirp signal d, and input the delayed chirp signal d to the correlator module 205;
wherein the integral multiple delay is equal to the sum of the delay of the correction source generation module and the delay of the digital phased array receiving channel.
The correlator module 205 is configured to perform a cross-correlation operation on the delayed chirp signal d and the multi-channel baseband I/Q data c to obtain correlation peak data e, and input the correlation peak data e to the delay calculation module 206;
the delay calculating module 206 is configured to perform peak searching and interpolation operation on the correlation peak data e to obtain a delay f at a peak value, and input the delay f to the synchronous chirp signal generating module 207;
the synchronous chirp signal generation module 207 is configured to generate a synchronous chirp signal g to the phase nonlinear calculation module 208 based on the delay f and the integer-times delay;
the phase nonlinearity calculation module 208 is configured to calculate a phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c.
The embodiment of the invention processes the broadband test chirp signals based on the correction source and the receiving channel of the digital phased array system, simultaneously measures the phase nonlinearity of all channels by utilizing the precise synchronous broadband chirp signals, has low algorithm software resource overhead and high measurement speed, and does not need auxiliary narrow pulse generation equipment and ultrahigh speed data acquisition equipment.
In one embodiment, the bandwidth of the baseband chirp signal a is the same as the channel bandwidth of the digital phased array receive channel, and the time-width bandwidth product of the baseband chirp signal a is not less than (360/δ)2/10SNRWhere δ (in degrees) is the phase non-linearity measurement error and SNR (in dB) is the signal-to-noise ratio of the baseband chirp signal a.
It should be noted that the time width of the baseband chirp signal a is much larger than the pulse width of the conventional single pulse method, the data sampling rate is much lower than the sampling rate of the conventional single pulse method, the hardware complexity and cost are greatly reduced, and the selection of the time-width product depends on the phase nonlinear measurement error and the signal-to-noise ratio of the baseband chirp signal a.
In an embodiment, the calibration source generating module 202 is specifically configured to:
and after digital-to-analog conversion, up-conversion, filtering and signal amplification processing are sequentially carried out on the baseband linear frequency modulation signal a by adopting the correction source, the broadband radio frequency linear frequency modulation signal b is generated, and the correction source is a correction source after inherent phase nonlinear self-calibration.
It should be noted that the inherent phase nonlinearity of the correction source can be self-calibrated by using oscilloscope data acquisition, predistortion filter coefficient calculation and digital predistortion compensation methods.
In an embodiment, the digital phased array receiving channel 203 is specifically configured to:
and the digital phased array receiving channel sequentially performs down-conversion, filtering, signal amplification and digital preprocessing on the broadband radio frequency linear frequency modulation signal b to obtain the multi-channel baseband I/Q data c.
In one embodiment, referring to fig. 5, the correlator module 205 includes:
the time domain overturning unit 205a is configured to perform time domain overturning on the delayed chirp signal d, and input the overturned signal to the convolution unit;
a conjugate taking unit 205b, configured to perform conjugate taking operation on the multiple paths of baseband I/Q data c, and input a signal after conjugate taking to the convolution unit;
the convolution unit 205c performs convolution operation on the time-domain reversed delay chirp signal and the conjugated multi-channel baseband I/Q data, and outputs the correlation peak data e.
In one embodiment, referring to fig. 6, the phase nonlinearity calculation module 208 includes:
the first phase calculation unit 208a is configured to perform phase calculation on the synchronous chirp signal g to obtain a first phase calculation result, and input the first phase calculation result to the difference calculation unit;
the second phase calculation unit 208b is configured to perform phase calculation on the multiple paths of baseband I/Q data c to obtain a second phase calculation result, and input the second phase calculation result to the difference calculation unit;
the difference calculation unit 208c is configured to perform difference operation on the first phase calculation result and the second phase calculation result, and input the difference result to the deskew calculation unit;
the deskew calculating unit 208d is configured to perform deskew operation on the difference result, remove a first-order linear component and a direct-current component, and output the phase nonlinearity h.
It should be noted that, in this embodiment, a phase difference and phase deskew method is comprehensively adopted, so that the algorithm complexity is low, and the measurement accuracy of phase nonlinearity is high.
It should be noted that other embodiments or implementations of the apparatus for measuring phase nonlinearity of a digital phased array receiver channel according to the present invention can refer to the above embodiments, and are not redundant herein.
In addition, referring to fig. 7, an embodiment of the present invention further provides a device for measuring phase nonlinearity of a digital phased array receiving channel, where the device includes a processor 100, a memory 200 storing program instructions, a bus 300, and a communication interface 400, where the processor 100, the communication interface 400, and the memory 200 are connected through the bus 300; the processor 100 is configured to perform the method as described in the above embodiments when executing the program instructions.
The memory 200 may include a Random Access Memory (RAM) and may further include a non-volatile memory (non-volatile memory), such as at least one disk memory. The communication connection between the network element of the system and at least one other network element is realized through at least one communication interface (which may be wired or wireless), and the internet, a wide area network, a local network, a metropolitan area network and the like can be used.
Furthermore, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the method described above.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (17)
1. A method for measuring phase nonlinearity of a digital phased array receive channel, the method comprising:
generating a baseband linear frequency modulation signal a, and correcting the baseband linear frequency modulation signal a based on a correction source to generate a broadband radio frequency linear frequency modulation signal b;
inputting the broadband radio frequency linear frequency modulation signal b into a digital phased array receiving channel to obtain multi-channel baseband I/Q data c;
carrying out integral-multiple time delay on the baseband linear frequency modulation signal a to obtain a time-delay linear frequency modulation signal d;
performing cross-correlation operation on the multi-channel baseband I/Q data c and the delayed linear frequency modulation signal d to obtain related peak data e;
performing peak value searching and interpolation operation on the related peak data e to obtain the delay f at the peak value;
generating a synchronous linear frequency modulation signal g based on the delay f and the integer cosy delay;
and calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c.
2. The method of claim 1, wherein the baseband chirp a has a same bandwidth as the channel bandwidth of the digital phased array receive channel, and a time-bandwidth product of the baseband chirp a is not less than (360/δ)2/10SNRWhere δ is the phase nonlinear measurement error and SNR is the signal-to-noise ratio of the baseband chirp signal a.
3. The method of claim 1, wherein the correcting the baseband chirp a based on a correction source to generate a wideband radio frequency chirp b, comprises:
and after digital-to-analog conversion, up-conversion, filtering and signal amplification processing are sequentially carried out on the baseband linear frequency modulation signal a by adopting the correction source, the broadband radio frequency linear frequency modulation signal b is generated, and the correction source is a correction source after inherent phase nonlinear self-calibration.
4. The method for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 1, wherein said inputting said wideband rf chirp signal b into the digital phased array receive channel to obtain multiple baseband I/Q data c comprises:
and the digital phased array receiving channel sequentially performs down-conversion, filtering, signal amplification and digital preprocessing on the broadband radio frequency linear frequency modulation signal b to obtain the multi-channel baseband I/Q data c.
5. The method of claim 3, wherein the integer multiple delay is equal to a sum of a delay of the calibration source generation module and a delay of the digital phased array receive channel.
6. The method for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 1, wherein said cross-correlating said multipath baseband I/Q data c with said delayed chirp signal d to obtain correlation peak data e comprises:
performing time domain turnover on the time-delay linear frequency modulation signal d;
performing conjugate operation on the multi-path baseband I/Q data c;
and performing convolution operation on the time-domain reversed time-delay linear frequency modulation signal and the multi-channel baseband I/Q data after conjugation, and outputting the related peak data e.
7. The method for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 1, wherein said performing a peak search and interpolation operation on said correlation peak data e to obtain a delay f at the peak comprises:
performing peak value searching operation on the related peak data e to obtain data samples near a peak value;
and calculating the delay f at the peak value by adopting a high-order polynomial interpolation algorithm based on the data samples near the peak value.
8. The method of claim 1, wherein the generation delay of the synchronous chirp g is the sum of the delay f and the integer coslay.
9. The method of claim 1, wherein the calculating the phase nonlinearity h of the digital phased array receive channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c comprises:
respectively carrying out phase calculation on the synchronous linear frequency modulation signal g and the multi-channel baseband I/Q data c to obtain phase calculation results;
performing difference calculation on the phase calculation result to obtain a difference result;
and performing deskew calculation on the difference result, removing a first-order linear component and a direct-current component, and outputting the phase nonlinearity h.
10. An apparatus for measuring phase nonlinearity of a digital phased array receive channel, the apparatus comprising:
the test chirp signal generation module is used for generating a baseband chirp signal a and inputting the baseband chirp signal a to the correction source generation module and the integral multiple delay module;
the correction source generation module is used for correcting the baseband linear frequency modulation signal a, outputting a broadband radio frequency linear frequency modulation signal b and feeding the broadband radio frequency linear frequency modulation signal b into a digital phased array receiving channel through a coupling network;
the digital phased array receiving channel is used for processing the broadband radio frequency linear frequency modulation signal b to form multi-channel baseband I/Q data c and inputting the multi-channel baseband I/Q data c to the correlator module;
the integral multiple time delay module is used for carrying out integral multiple clock cycle time delay on the baseband linear frequency modulation signal a to obtain a time delay linear frequency modulation signal d and inputting the time delay linear frequency modulation signal d to the correlator module;
the correlator module is used for performing cross-correlation operation on the delayed linear frequency modulation signal d and the multi-channel baseband I/Q data c to obtain related peak data e and inputting the related peak data e to the delay calculation module;
the time delay calculation module is used for performing peak value searching and interpolation operation on the related peak data e to obtain time delay f at a peak value and inputting the time delay f to the synchronous linear frequency modulation signal generation module;
the synchronous linear frequency modulation signal generating module is used for generating a synchronous linear frequency modulation signal g to the phase nonlinear computing module based on the delay f and the integral multiple delay;
and the phase nonlinearity calculation module is used for calculating the phase nonlinearity h of the digital phased array receiving channel based on the synchronous chirp signal g and the multi-path baseband I/Q data c.
11. The apparatus for measuring phase nonlinearity of a digital phased array receive channel as defined in claim 10, wherein the bandwidth of the baseband chirp signal a is the same as the channel bandwidth of the digital phased array receive channel, and the time-bandwidth product of the baseband chirp signal a is not less than (360/δ)2/10SNRWhere δ is the phase nonlinear measurement error and SNR is the signal-to-noise ratio of the baseband chirp signal a.
12. The apparatus for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 10, wherein said calibration source generation module is specifically configured to:
and sequentially performing digital-to-analog conversion, up-conversion, filtering and signal amplification on the baseband linear frequency modulation signal a to generate a broadband radio frequency linear frequency modulation signal b.
13. The apparatus of claim 10, wherein the integer multiple delay is equal to a sum of a delay of the calibration source generation module and a delay of the digital phased array receive channel.
14. The apparatus for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 10, wherein said correlator module comprises:
the time domain overturning unit is used for carrying out time domain overturning on the time delay linear frequency modulation signal d and inputting the overturned signal into the convolution unit;
a conjugate taking unit, configured to perform conjugate taking operation on the multi-path baseband I/Q data c, and input a signal after conjugate taking to the convolution unit;
and the convolution unit is used for performing convolution operation on the time-domain reversed time-delay linear frequency modulation signal and the conjugated multi-channel baseband I/Q data and outputting the related peak data e.
15. The apparatus for measuring phase nonlinearity of a digital phased array receive channel as claimed in claim 10, wherein said phase nonlinearity calculation module comprises:
the first phase calculation unit is used for carrying out phase calculation on the synchronous linear frequency modulation signal g to obtain a first phase calculation result and inputting the first phase calculation result to the difference value calculation unit;
the second phase calculation unit is used for carrying out phase calculation on the multi-channel baseband I/Q data c to obtain a second phase calculation result and inputting the second phase calculation result to the difference calculation unit;
the difference calculation unit is used for performing difference operation on the first phase calculation result and the second phase calculation result and inputting the difference result to the deskew calculation unit;
and the deskew calculation unit is used for carrying out deskew operation on the difference result, removing a first-order linear component and a direct-current component and outputting the phase nonlinearity h.
16. A measuring device for phase nonlinearity of a digital phased array receiving channel is characterized by comprising a memory and a processor; wherein the processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory for implementing the method according to any one of claims 1 to 9.
17. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method according to any one of claims 1-9.
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