CN108737308B - Peak factor reduction method and device - Google Patents
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Abstract
Disclosure of the present applicationA crest factor reduction method and device are provided, wherein the method comprises the following steps: shunting a current signal to be clipped to obtain a first path of signal and a second path of signal; carrying out time delay processing on the first path of signal, generating single-point complex noise of the second path of signal in each detection window according to a preset detection window, and multiplying each single-point complex noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the end of the shunt to the generation of the first clipping noise, tn‑tn‑1≥Len，2≤n，tnThe sampling point position, t, of the second path signal corresponding to the nth single-point complex value noise is generatedn‑1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient; and subtracting the first path of signal after the clipping noise and the delay processing to obtain the clipping processing result of the signal to be clipped. The invention can realize the CFR function and has low cost.
Description
Technical Field
The present invention relates to mobile communication technology, and more particularly, to a Crest Factor Reduction (CFR) method and apparatus.
Background
In order to reduce the peak-to-average ratio of the signal, many peak factor reduction methods have been proposed, wherein the clipping-like CFR method is a simpler method and its principle is as follows: before the signal is sent to the amplifier, the signal with larger peak power is pre-distorted through nonlinear processing, so that the working point of the power amplifier is as close as possible to the tail end of the linear working area, and the power amplification efficiency is improved.
In a 4G wireless communication base station, a common clipping CFR method includes: peak windowed crest factor reduction (PW-CFR), noise shaped crest factor reduction (NS-CFR), pulse injection crest factor reduction (PI-CFR), peak cancellation crest factor reduction (PC-CFR), and the like. In the implementation process of the method, the peak value and the clipping coefficient are multiplied to generate the cancellation pulse, and the number of the multipliers required to be consumed is in direct proportion to the number of the detected peak values.
At the present stage, a plurality of 4G wireless communication base stations use a Field Programmable Gate Array (FPGA) to perform digital intermediate frequency processing, and multipliers in the FPGA are a class of resources with limited quantity. When the amplitude limiting CFR method is adopted, if the occupancy rate of FPGA multiplier resources in the CFR realization process is reduced, high PAPR signal omission is caused, so that the CFR clipping performance is reduced, the aim of protecting a radio frequency power amplifier is not achieved, and if a better CFR effect is realized, a large amount of multiplier resources are consumed. Therefore, the conventional clipping CFR method cannot be widely applied to 4G systems due to the large multiplier overhead.
Disclosure of Invention
In view of the above, the main objective of the present invention is to provide a crest factor reduction method and apparatus, which can implement CFR function and have small multiplier overhead.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a crest factor reduction method, comprising:
shunting a current signal to be clipped to obtain a first path of signal and a second path of signal;
carrying out time delay processing on the first path of signal, simultaneously generating single-point complex value noise of the second path of signal in each detection window according to a preset detection window, and multiplying each single-point complex value noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient;
and subtracting the first path of signal after the delay processing from the clipping noise to obtain a clipping processing result of the signal to be clipped.
A crest factor reduction device, comprising:
the branch module is used for branching a current signal to be clipped to obtain a first path of signal and a second path of signal;
clipping noise generation module, usingCarrying out time delay processing on the first path of signal, simultaneously generating single-point complex noise of the second path of signal in each detection window according to a preset detection window, and multiplying each single-point complex noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient;
and the clipping processing module is used for subtracting the first path of signal after the clipping noise and the delay processing to obtain a clipping processing result of the signal to be clipped.
In summary, the peak factor reduction method and apparatus provided by the present invention ensure tn-tn-1The sampling point number of the interval between the adjacent single-point complex value noises is larger than or equal to the length of the clipping coefficient, so that the clipping noise is obtained by multiplying one complex value noise by the clipping coefficient each time, and thus, only one multiplier is needed when the clipping noise is generated each time, so that only one FPGA multiplier resource is used during CFR processing, the CFR function is realized, meanwhile, the multiplier cost is reduced, and further, the cost of the 4G wireless communication base station is reduced.
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FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The core idea of the invention is as follows: the number of sampling points spaced between adjacent single-point complex value noises is larger than or equal to the length of the clipping coefficient, so that the clipping noise is obtained by multiplying one complex value noise by the clipping coefficient at each time, and only one multiplier is needed when the clipping noise is generated at each time, therefore, the cost of the multiplier can be greatly reduced while the CFR function is realized, and the cost of the 4G wireless communication base station is further reduced.
Fig. 1 is a schematic flow chart of an embodiment of the present invention, and as shown in fig. 1, the method for reducing the crest factor implemented in the embodiment mainly includes:
The step is used for shunting the signal to be clipped, so as to obtain clipping noise based on the signal to be clipped by using one path of signal in the subsequent step, and then subtract the other path of signal by using the clipping noise, thereby obtaining the clipping processing result of the signal to be clipped.
In practical applications, the determination of the signal to be clipped is the same as in the existing schemes, i.e. signals with high peak-to-average power ratio (PAPR).
And 102, carrying out time delay processing on the first path of signal, simultaneously generating single-point complex noise of the second path of signal in each detection window according to a preset detection window, and multiplying each single-point complex noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise.
Wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1And the Len is the length of the clipping coefficient, and is the sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise.
In practical applications, the detection window may be set by using a sliding window method, but is not limited thereto, and the specific length L of the detection window may be set by a person skilled in the art according to actual needs.
In this step, t is required to be satisfiedn-tn-1And the number of complex value noises of the clipping noise obtained by multiplying the clipping coefficient each time is equal to or more than Len, namely, the number of single point complex value noises of a detection window, so that only one multiplier is needed when the clipping noise is generated each time, and the cost of the multiplier is greatly reduced while the CFR function is realized.
In this step, the first path of signal needs to be delayed, and the delay amount is the processing time from the end of the branching to the generation of the first clipping noise, so as to ensure the function and performance of clipping, and thus, the clipping of the signal to be clipped can be realized. The specific delay processing may be implemented by using a Random Access Memory (RAM), but is not limited thereto.
In this step, the second path of signal needs to be processed to obtain the single-point complex noise of the second path of signal in each detection window, and obtain the corresponding clipping noise based on the single-point complex noise.
Preferably, in order to further ensure the CFR performance, in practical applications, the maximum peak value of the second path signal in each detection window may be used to generate corresponding single-point complex noise, and this can be achieved by a variety of methods, and the following four specific implementation methods are given to describe this in detail.
The method comprises the following steps:
and a1, extracting the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal.
In this step, the amplitude and phase information of the signal may be extracted by using an existing method, for example, the amplitude and phase information of the other cfr _ in signal may be extracted by using a serial mode of Cordic algorithm modules in a vectoring mode of 6 stages. Wherein, the input-output relationship of each stage is as follows:
Ik+1＝Ik-σk·2-k·Qk
Qk+1＝Qk+σk·2-k·Ik
Phk+1＝Phk-σktan-1(2-k)
wherein k is an iterative series of 0 to 5,
the initial values at the start of the iteration are respectively I0＝cfr_in_i，Q0＝cfr_in_q，Ph0And 0, the cfr _ in _ i and the cfr _ in _ q are respectively a real part and an imaginary part of the second signal cfr _ in. I of last stage Cordic _ vent output5Amplitude of the second signal cfr _ in after gain adjustment, and Ph5As the phase of the second signal cfr _ in, tan-1(2-k) And obtaining the k value by means of table look-up.
In practical applications, the method for extracting the amplitude and phase information of the signal is not limited to the above method, and will not be described herein again.
Step a2, using a threshold-crossing decision device (clipper) to perform noise threshold decision processing on the amplitude signal to obtain a noise amplitude signal.
In this step, the method is configured to perform clipper processing on the amplitude signal extracted in step a1, and screen out an amplitude signal whose amplitude is greater than a preset CFR threshold value, and generate a corresponding noise amplitude signal. The specific clipper processing rules are as follows:
where c (n) is the output signal of clipper, x (n) is the input signal of clipper, and CFR _ th is the predetermined CFR threshold.
Step a3, detecting the maximum non-zero value of the noise amplitude signal in each detection window in turn, and generating the single-point complex value noise by using the maximum non-zero value and the corresponding phase in the phase signal.
In this step, in each detection window, only the maximum non-zero value in the noise amplitude signal is detected, and the single-point complex value noise is generated by using the maximum non-zero value, so that the obtained single-point complex value noise is the noise with the maximum amplitude corresponding to the detection window, and the clipping noise is generated by using the single-point complex value noise to clip the original signal, thereby realizing the CFR function.
Specifically, the present step may be implemented by using an existing complex-valued noise generation method. For example, the complex-valued noise can be generated by adopting a Cordic algorithm cascade mode of a 6-level rotation mode according to an actual application scene and a simulation result. Wherein, the input-output relationship of each stage is as follows:
Ik+1＝Ik-σk·2-k·Qk
Qk+1＝Qk+σk·2-k·Ik
Phk+1＝Phk-σk·tan-1(2-k)
wherein k is an iterative series of 0 to 5,
the initial values for the start of the iteration are respectively I0＝peak_mag，Q0＝0，Ph0Peak _ mag and peak _ pha are the amplitude and phase of the peak point, respectively. I of last stage Cordic _ rot output5、Q5The real and imaginary parts of the complex-valued noise, tan, are obtained after gain adjustment-1(2-k) And obtaining the k value by means of table look-up.
The second method comprises the following steps:
and b1, extracting the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal.
The specific implementation of this step is the same as step a1, and will not be described herein again.
And b2, performing noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment clipper to obtain a noise amplitude signal.
The specific implementation of this step is the same as step a2, and thus, the detailed description thereof is omitted.
And b3, converting the noise amplitude signal into a preset M paths of parallel noise amplitude signals.
In order to increase the generation speed of the single-point complex-valued noise, the noise amplitude signal is converted into M paths of parallel signals by using serial-parallel conversion.
B4, detecting the maximum non-zero value of each path of noise amplitude signal in the detection window after conversion in a mode of parallel processing of M paths of signals in each detection window, and selecting the maximum value from all the maximum non-zero values in the detection window; and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase in the phase signal.
In step b4, in order to increase the generation speed of the single-point complex noise in each detection window, M paths of signals are processed in parallel in each detection window, the maximum non-zero value of the amplitude signal of each path of noise in the detection window is detected, a maximum value is selected from the M maximum non-zero values, and the maximum value is multiplied by the corresponding phase in the phase signal extracted in step b1 to obtain the single-point complex noise in the detection window. Here, since M paths of signals are processed in parallel, the detection window in the method may be set to be smaller, and the detection window in the method may have a length of L/M compared to the detection window L in the method 1, in which serial-to-parallel conversion is not introduced.
The third method comprises the following steps:
and c1, performing serial-parallel conversion on the second path of signals to obtain M paths of parallel signals.
And c2, determining the amplitude and phase of the single-point complex noise of each path of signal in each detection window for each path of signal after serial-parallel conversion in a mode of parallel processing of M paths of signals.
Wherein the determining comprises: extracting amplitude and phase of the ith path of signal after the serial-parallel conversion to obtain an amplitude signal and a phase signal; performing noise threshold decision processing on the amplitude signal by using a threshold decision device (clipper) to obtain a noise amplitude signal; and sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window according to the detection windows, taking the maximum non-zero value as the amplitude of the single-point complex value noise of the ith path of signal in the detection window, and taking the corresponding phase of the maximum non-zero value in the phase signal as the phase of the single-point complex value noise of the ith path of signal in the detection window.
Step c3, for each detection window, selecting the maximum amplitude from the determined amplitudes of all the M paths of signals, and generating the single-point complex noise of the detection window by using the maximum amplitude and the corresponding phase.
The method four comprises the following steps:
and d1, extracting the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal.
The specific implementation of this step is the same as step a1, and will not be described herein again.
And d2, performing serial-to-parallel conversion on the amplitude signals to obtain M paths of parallel amplitude signals.
D3, determining the maximum noise amplitude of each path of amplitude signal in each detection window after the serial-parallel conversion by adopting an M-path signal parallel processing mode; wherein the determining comprises: and performing noise threshold judgment processing on the ith path of amplitude signal after the serial-parallel conversion by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and taking the maximum non-zero value as the maximum noise amplitude of the ith path of amplitude signal in the corresponding detection window.
Step d4, for each detection window, selecting the maximum value from the maximum noise amplitudes of all the M paths of signals, and using the maximum value and the corresponding phase of the phase signal to generate the single-point complex noise of the detection window.
The serial-parallel conversion technology is introduced into the second, third and fourth methods, so that parallel processing of multiple paths of signals can be realized, and the detection window is greatly reduced to be 1/M of the detection window in the first method, so that the generation efficiency of single-point complex noise can be greatly improved compared with the first method.
And 103, subtracting the clipping noise from the delayed first path signal to obtain a clipping processing result of the signal to be clipped.
Fig. 2 is a schematic structural diagram of a crest factor reduction device corresponding to the above method, as shown in fig. 2, the device includes:
the branch module is used for branching a current signal to be clipped to obtain a first path of signal and a second path of signal;
the clipping noise generation module is used for carrying out time delay processing on the first path of signal, generating single-point complex value noise of the second path of signal in each detection window according to a preset detection window, and multiplying each single-point complex value noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient;
and the clipping processing module is used for subtracting the first path of signal after the clipping noise and the delay processing to obtain a clipping processing result of the signal to be clipped.
Preferably, the clipping noise generation module includes a noise generation unit;
the noise generating unit is used for extracting and processing the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal; and sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and generating the single-point complex-value noise by using the maximum non-zero value and the corresponding phase in the phase signal.
Preferably, the clipping noise generation module includes a noise generation unit;
the noise generating unit is used for extracting and processing the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal; converting the noise amplitude signal into a preset M-path parallel noise amplitude signal; in each detection window, detecting the maximum non-zero value of each converted noise amplitude signal in the detection window by adopting an M-channel signal parallel processing mode, and selecting the maximum value from all the maximum non-zero values in the detection window; and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase in the phase signal.
Preferably, the clipping noise generation module includes a noise generation unit;
the noise generating unit is used for performing serial-parallel conversion on the second path of signals to obtain M paths of parallel signals; determining the amplitude and the phase of the single-point complex noise of each path of signals in each detection window by adopting a mode of parallel processing of M paths of signals for each path of signals after serial-parallel conversion; wherein the determining comprises: extracting amplitude and phase of the ith path of signal after the serial-parallel conversion to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal; sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window according to the detection windows, taking the maximum non-zero value as the amplitude of the single-point complex value noise of the ith path of signal in the detection window, and taking the corresponding phase of the maximum non-zero value in the phase signal as the phase of the single-point complex value noise of the ith path of signal in the detection window; and for each detection window, selecting the maximum amplitude from the determined amplitudes of all the M paths of signals, and generating the single-point complex value noise of the detection window by using the maximum amplitude and the corresponding phase.
Preferably, the clipping noise generation module includes a noise generation unit;
the noise generating unit is used for extracting and processing the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal; performing serial-to-parallel conversion on the amplitude signals to obtain M paths of parallel amplitude signals; determining the maximum noise amplitude of each path of amplitude signal in each preset detection window after the serial-parallel conversion by adopting an M-path signal parallel processing mode; wherein the determining comprises: performing noise threshold judgment processing on the ith path of amplitude signal after serial-parallel conversion by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and taking the maximum non-zero value as the maximum noise amplitude of the ith path of amplitude signal in the corresponding detection window; for each detection window, selecting a maximum value from the maximum noise amplitudes of all the M paths of signals, and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase of the phase signal.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A crest factor reduction method, comprising:
shunting a current signal to be clipped to obtain a first path of signal and a second path of signal;
the first path of signal is delayed, meanwhile, according to a preset detection window, the maximum peak value in the detection window is utilized to generate single-point complex value noise of the second path of signal in each detection window, and each single-point complex value noise and a preset clipping system are sequentially combinedMultiplying by a number to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient;
the generating of the single-point complex-valued noise of the second path of signal in each detection window comprises:
extracting amplitude and phase of the second path of signal to obtain an amplitude signal and a phase signal;
carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal;
or the generating of the single-point complex-valued noise of the second path of signal in each detection window comprises:
extracting amplitude and phase of each path of signal after the second path of signal is subjected to serial-parallel conversion to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal;
or the generating of the single-point complex-valued noise of the second path of signal in each detection window comprises:
extracting amplitude and phase of the second path of signal to obtain an amplitude signal and a phase signal;
performing noise threshold judgment processing on each path of amplitude signal after the amplitude signal is subjected to serial-parallel conversion by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal;
the clipper processing rules include:
where c (n) is the output signal of clipper, x (n) is the input signal of clipper, and CFR _ th is the predetermined CFR threshold.
2. The method of claim 1, wherein generating the single point complex noise for the second path of signals in each detection window further comprises:
and sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and generating the single-point complex-value noise by using the maximum non-zero value and the corresponding phase in the phase signal.
3. The method of claim 1, wherein generating the single point complex noise for the second path of signals in each detection window further comprises:
converting the noise amplitude signal into a preset M-path parallel noise amplitude signal;
in each detection window, detecting the maximum non-zero value of each converted noise amplitude signal in the detection window by adopting an M-channel signal parallel processing mode, and selecting the maximum value from all the maximum non-zero values in the detection window; and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase in the phase signal.
4. The method of claim 1, wherein generating the single point complex noise for the second path of signals in each detection window further comprises:
performing serial-parallel conversion on the second path of signals to obtain M paths of parallel signals;
determining the amplitude and the phase of the single-point complex noise of each path of signals in each detection window by adopting a mode of parallel processing of M paths of signals for each path of signals after serial-parallel conversion; wherein the determining further comprises: after the ith path of signal after the serial-parallel conversion is subjected to the noise amplitude signal, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window according to the detection windows, taking the maximum non-zero value as the amplitude of the single-point complex noise of the ith path of signal in the detection window, and taking the corresponding phase of the maximum non-zero value in the phase signal as the phase of the single-point complex noise of the ith path of signal in the detection window;
and for each detection window, selecting the maximum amplitude from the determined amplitudes of all the M paths of signals, and generating the single-point complex value noise of the detection window by using the maximum amplitude and the corresponding phase.
5. The method of claim 1, wherein generating the single point complex noise for the second path of signals in each detection window further comprises:
performing serial-to-parallel conversion on the amplitude signals to obtain M paths of parallel amplitude signals;
determining the maximum noise amplitude of each path of amplitude signal in each detection window after the serial-parallel conversion by adopting an M-path signal parallel processing mode; wherein the determining further comprises: after the ith path of amplitude signal after the serial-parallel conversion is subjected to noise threshold judgment processing, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and taking the maximum non-zero value as the maximum noise amplitude of the ith path of amplitude signal in the corresponding detection window;
for each detection window, selecting a maximum value from the maximum noise amplitudes of all the M paths of signals, and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase of the phase signal.
6. A crest factor reduction device, comprising:
the branch module is used for branching a current signal to be clipped to obtain a first path of signal and a second path of signal;
a clipping noise generation module for delaying the first path of signal and simultaneously generating a clipping noiseGenerating single-point complex-valued noise of the second path of signal in each detection window by using the maximum peak value in the detection window according to a preset detection window, and multiplying each single-point complex-valued noise by a preset clipping coefficient in sequence to obtain corresponding clipping noise; wherein, the delay amount adopted by the delay processing is the processing time length from the branching end to the generation of the first clipping noise, tn-tn-1More than or equal to Len, more than or equal to 2 and less than or equal to n, and the tnThe sampling point position of the second path of signal corresponding to the generated nth single-point complex value noise, the tn-1The sampling point position of the second path of signal corresponding to the generated n-1 th single-point complex value noise is obtained, and Len is the length of the clipping coefficient;
the clipping processing module is used for subtracting the first path of signal after the clipping noise and the delay processing to obtain a clipping processing result of the signal to be clipped;
the clipping noise generation module includes a noise generation unit;
the noise generating unit is used for extracting and processing the amplitude and the phase of the second path of signal to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal; or, performing amplitude and phase extraction processing on each path of signal after the second path of signal is subjected to serial-parallel conversion to obtain an amplitude signal and a phase signal; carrying out noise threshold judgment processing on the amplitude signal by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal; or, extracting amplitude and phase of the second path of signal to obtain an amplitude signal and a phase signal; performing noise threshold judgment processing on each path of amplitude signal after the amplitude signal is subjected to serial-parallel conversion by using a threshold-crossing judgment device clipper to obtain a noise amplitude signal;
the clipper processing rules include:
where c (n) is the output signal of clipper, x (n) is the input signal of clipper, and CFR _ th is the predetermined CFR threshold.
7. The apparatus of claim 6,
the noise generating unit is further configured to sequentially detect a maximum non-zero value of the noise amplitude signal in each detection window, and generate the single-point complex noise by using the maximum non-zero value and a corresponding phase in the phase signal.
8. The apparatus of claim 6,
the noise generating unit is further configured to convert the noise amplitude signal into preset M paths of parallel noise amplitude signals; in each detection window, detecting the maximum non-zero value of each converted noise amplitude signal in the detection window by adopting an M-channel signal parallel processing mode, and selecting the maximum value from all the maximum non-zero values in the detection window; and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase in the phase signal.
9. The apparatus of claim 6,
the noise generating unit is further configured to perform serial-to-parallel conversion on the second channel of signals to obtain M channels of parallel signals; determining the amplitude and the phase of the single-point complex noise of each path of signals in each detection window by adopting a mode of parallel processing of M paths of signals for each path of signals after serial-parallel conversion; wherein the determining further comprises: after the ith path of signal after the serial-parallel conversion is subjected to the noise amplitude signal, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window according to the detection windows, taking the maximum non-zero value as the amplitude of the single-point complex noise of the ith path of signal in the detection window, and taking the corresponding phase of the maximum non-zero value in the phase signal as the phase of the single-point complex noise of the ith path of signal in the detection window; and for each detection window, selecting the maximum amplitude from the determined amplitudes of all the M paths of signals, and generating the single-point complex value noise of the detection window by using the maximum amplitude and the corresponding phase.
10. The apparatus of claim 6,
the noise generating unit is further configured to perform serial-to-parallel conversion on the amplitude signal to obtain M paths of parallel amplitude signals; determining the maximum noise amplitude of each path of amplitude signal in each preset detection window after the serial-parallel conversion by adopting an M-path signal parallel processing mode; wherein the determining further comprises: after the ith path of amplitude signal after the serial-parallel conversion is subjected to noise threshold judgment processing, sequentially detecting the maximum non-zero value of the noise amplitude signal in each detection window, and taking the maximum non-zero value as the maximum noise amplitude of the ith path of amplitude signal in the corresponding detection window; for each detection window, selecting a maximum value from the maximum noise amplitudes of all the M paths of signals, and generating the single-point complex noise of the detection window by using the maximum value and the corresponding phase of the phase signal.
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