Phase noise measurement method, system and storage medium based on spectrum analysis

Abstract

The present invention provides a phase noise measurement method and system based on spectrum analysis, and a storage medium, wherein the method steps include: iteratively calculating #imgabs0# and the ADC operating frequency #imgabs1#; setting the ADC chip operating frequency to #imgabs2#, reading data to obtain the index value SI corresponding to the input signal frequency point; recording the phase noise point data of the first or second range of SI in the FFTL to the phase noise table PNL according to whether the phase noise point data length of the FFTL coincides with the RBW, and correspondingly exiting the loop or continuing the iterative calculation; similarly setting the ADC chip frequency to F, obtaining the corresponding index value NSI; recording the phase noise point data of the third range of NSI to the PNL; setting the phase noise index table PNIL to record the data index, measurement frequency and resolution bandwidth corresponding to the phase noise point data value in the PNL; and calculating the corresponding phase noise according to the value index PNIL.

Description

Technical Field

[0001] The present invention relates to the technical field of phase noise measurement, and in particular to a phase noise measurement method and system based on spectrum analysis, and a storage medium. Background Art

[0002] Spectrum analysis is the oldest, most direct, and most widely used method for phase noise measurement. However, spectrum analysis cannot typically measure low-frequency phase noise directly. Instead, it can only be calculated using a normalized method, namely, N = 10*log(RBW in Hz).

[0003] For example, using spectrum analysis, if the ADC chip's operating frequency is 125 MHz and the sampling rate is 65,536, the RBW (resolution bandwidth) is approximately 1.907 kHz (125 MHz / 65,536). This means that phase noise below 1.907 kHz (1 Hz, 10 Hz, 100 Hz, 1 kHz) cannot be directly measured.

[0004] Therefore, in phase noise measurement, spectrum analysis methods are generally limited by RBW, resulting in the inability to directly measure phase noise at low frequencies. Summary of the Invention

[0005] To this end, the main purpose of the present invention is to provide a phase noise measurement method and system based on spectrum analysis, and a storage medium to solve the problems mentioned in the background technology.

[0006] To achieve the above object, according to one aspect of the present invention, a phase noise measurement method based on spectrum analysis is provided, comprising the following steps:

[0007] Determine the resolution bandwidth (RBW) based on the maximum data length (S) that can be processed and the operating frequency (F) of the ADC chip.

[0008] According to the preset iteration condition N, the iterative calculation includes:

[0009] Under current conditions and ADC operating frequency ;

[0010] Set the ADC chip operating frequency to , read the data to establish the frequency data table FFTList, and obtain the index value SI corresponding to the input signal frequency point;

[0011] When it is determined that the phase noise point data length of FFTList coincides with RBW, the phase noise point data of the first range of SI in FFTList is recorded to the phase noise table, and the loop is exited; otherwise, the phase noise point data of the second range of SI is recorded to the phase noise table, and the iterative calculation continues;

[0012] Set the operating frequency of the ADC chip to F, read the data to establish a frequency data table NFFTList, and obtain the index value NSI corresponding to the input signal frequency point therein; record the phase noise point data within the measurement frequency range covered by NSI into the phase noise table;

[0013] Set the phase noise index table to record the data index, measurement frequency, and resolution bandwidth rbw corresponding to the phase noise point data value in the phase noise table;

[0014] Obtain the corresponding value from the phase noise table according to the measurement frequency, and calculate the corresponding phase noise PN = value - 10 * log10(rbw) - fund, where fund is the fundamental signal value.

[0015] In a possible preferred embodiment, the step of determining the resolution bandwidth RBW includes:

[0016] Calculate RBW = a * , where P = ceil(log10(F / S)), and a is a frequency Hz adjustment parameter and a > 0.

[0017] In a possible preferred embodiment, the preset iteration condition N is:

[0018] The initial condition is N = 0, the termination condition is N < P, and N is incremented by 1 each time, where P = ceil(log10(F / S)).

[0019] In a possible preferred embodiment, where and The calculation steps include:

[0020] Calculate <00 / / = a * ;

[0021] Calculate = * S;

[0022] where a is a frequency Hz adjustment parameter and a > / /

[0023] In a possible preferred embodiment, the first range and the second range of the index value SI are respectively:

[0024] The first range of the index value SI: SI + 1 to SI + 1 + RBW / ;

[0025] The second range of the index value SI: SI + 1 to SI + a * / ;

[0026] Where a is the frequency Hz adjustment parameter and a>0.

[0027] In a possible preferred embodiment, the index value NSI covers the measurement frequency range of interest as follows:

[0028] NSI+1 to NSI+a*(10* ) / RBW, where a is the frequency Hz adjustment parameter and a>0.

[0029] In a possible preferred embodiment, the step of determining whether the phase noise point data length of FFTList coincides with the RBW includes:

[0030] Calculate the phase noise point data length PNDataLength = FS-SI-1; where FS is half of the maximum data length S that can be processed currently;

[0031] Only when PNDataLength* ≥ RBW, it is determined that PNDataLength coincides with RBW.

[0032] In a possible preferred embodiment, the step of calculating the corresponding phase noise according to the value index phase noise index table includes:

[0033] Get the corresponding value from the phase noise table according to the measured frequency and calculate the corresponding phase noise PN:

[0034] PN = value-10*log10(rbw)-fund, where fund is the fundamental signal value.

[0035] In order to achieve the above-mentioned purpose, corresponding to the above-mentioned method, according to another aspect of the present invention, a phase noise measurement system based on spectrum analysis is also provided, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of any of the above-mentioned phase noise measurement methods based on spectrum analysis.

[0036] In order to achieve the above-mentioned purpose, corresponding to the above-mentioned method, according to another aspect of the present invention, a computer-readable storage medium is further provided, wherein the computer-readable storage medium stores a computer program, wherein when the computer program is executed, the steps of any of the above-mentioned phase noise measurement methods based on spectrum analysis are implemented.

[0037] The spectrum analysis-based phase noise measurement method, system, and storage medium provided by the present invention utilize a cleverly designed iterative algorithm based on spectrum analysis. During each iteration, the ADC chip sets the resolution bandwidth, ensuring that the resolution bandwidth reaches the desired low-frequency region. This ensures that the required low-frequency spectrum data is obtained for calculating the corresponding phase noise. This effectively addresses the traditional inability to directly measure low-frequency phase noise due to RBW limitations. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 Schematic diagram of the steps of the phase noise measurement method based on spectrum analysis of the present invention;

[0040] Figure 2 It is a structural diagram of the phase noise measurement system based on spectrum analysis of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the specific technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments to help those skilled in the art further understand the present invention. Obviously, the embodiments described in this case are only embodiments of a part of the present invention, rather than all embodiments. It should be pointed out that, for those of ordinary skill in the art, the embodiments in this application and the features in the embodiments can be combined with each other without departing from the concept of the present invention and without conflicting with each other. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the disclosure and protection scope of the present invention.

[0042] In addition, the terms "first," "second," "S100," "S200," and the like in the specification, claims, and drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that the features used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be implemented in an order other than that described herein. Furthermore, the stages described in each step are not necessarily implemented in the same step. It should be understood that the order of implementation of each stage can be adjusted and interchanged without violating the inventive concept, such that the step embodiments of the present invention described herein can be implemented in an order other than that described herein. Furthermore, the terms "including," "having," and any variations thereof, as used herein, are intended to cover non-exclusive inclusions. Unless otherwise expressly specified or limited, the terms "disposed," "arranged," "installed," "connected," and "connected" should be interpreted broadly, for example, to mean fixed, removable, or integral; mechanical or electrical; direct or indirect through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this case based on specific circumstances and in conjunction with prior art.

[0043] In phase noise measurement, spectrum analysis methods are generally limited by the RBW (resolution bandwidth), making it impossible to directly measure low-frequency phase noise. Lowering the RBW (e.g., to 1Hz, 10Hz) prevents the spectrum data from covering the high-frequency region (1M, 10M). Therefore, spectrum analysis methods typically use an RBW above 1kHz, and then calculate low-frequency phase noise using normalization.

[0044] To this end, the present invention designs an iterative algorithm based on spectrum analysis to be used with an ADC chip to directly measure the frequency of interest in phase noise measurement, while also improving measurement precision while still ensuring accuracy.

[0045] For this reason, Figure 1 As shown, the present invention provides a phase noise measurement method based on spectrum analysis, and its exemplary steps include:

[0046] Step S100 determines the resolution bandwidth (RBW) according to the maximum data length (S) that can be processed currently and the operating frequency (F) of the ADC chip.

[0047] Specifically, in order to calculate the most appropriate RBW based on F and S, first divide F by S to get , which is the minimum RBW at the ADC operating frequency, and then use Calculate log10 and round up the result to get P. That is, when the working frequency of the ADC chip is F, the most suitable RBW is 10 to the power of P multiplied by a, where a is the frequency adjustment parameter in Hz and a > 0.

[0048] The example pseudo-code is as follows:

[0049] = F / S

[0050] P = ceil(log10(F / S))

[0051] RBW = a *

[0052] Step S200 iteratively calculates according to the preset iteration condition N, including: under the current condition and the ADC working frequency ; Set the working frequency of the ADC chip to , read data to establish the frequency data table FFTList, and obtain the index value SI corresponding to the input signal frequency point therein; when it is judged that the length of the phase noise point data in FFTList coincides with RBW, record the phase noise point data in the first range of SI in the phase noise table, jump out of the loop, otherwise record the phase noise point data in the second range of SI in the phase noise table and continue the iterative calculation.

[0053] Specifically, first set the phase noise table PhaseNoiseList to record the phase noise point data. At the same time, set the phase noise index table PhaseNoiseIndexList to record the data index index, measurement frequency freq, and resolution bandwidth rbw corresponding to the phase noise point data value in the phase noise table PhaseNoiseList. The data information in PhaseNoiseIndexList does not have to correspond one-to-one with PhaseNoiseList, and only important information needs to be recorded.

[0054] Then add a value to PhaseNoiseList for placeholder (it will be replaced in the subsequent process), start the iterative process, the iteration condition is N, the initial condition is N = 0, the termination condition is N < P, and N is incremented by 1 each time. The process is as follows:

[0055] Step S201 calculates the RBW under the current condition, defined as = a * ;

[0056] Step S202 calculates the ADC working frequency under the current condition, defined as = * S;

[0057] Step S203 sets the ADC chip operating frequency to (By setting the clock chip or clock device associated with the ADC, the unit is Hz); read data from the ADC chip, named DataList, the length of DataList is S; perform Fourier transform on DataList to obtain the frequency data table FFTList, the length of FFTList is half of DataList, defined as FS; then search the input signal frequency point in FFTList (that is, the point with the largest value in the frequency data), and obtain the index value of the input signal frequency point (the index value starts with 0, the same below), defined as SI (that is, SignalIndex).

[0058] Each data point after the index SignalIndex represents a , that is, FFTList[SignalIndex+1] is the frequency Phase noise point data, FFTList[SignalIndex+100] is the frequency *Phase noise data at 100 points.

[0059] Step S204 calculates the phase noise data length in FFTList, which is defined as PNDataLength, where PNDataLength = FS-SI-1; where FS is half of the maximum data length S that can be processed currently.

[0060] Step S205 determines whether PNDataLength coincides with RBW. :

[0061] 1) If PNDataLength* RBW is considered to be overlapping.

[0062] At this time, you need to record the data information of interest and add it to PhaseNoiseIndexList. This step is a small loop. The loop variable is defined as t, and the starting condition is t= , the termination condition is t≤RBW, each cycle t is multiplied by 10 (index is the length of PhaseNoiseList+t+1, freq is *t, rbw is ). Then record the phase noise point data of the first range of SI in FFTList to the phase noise table and jump out of the loop. The first range is index SignalIndex+1 to SignalIndex+1+RBW / .

[0063] 2) If PNDataLength* If <RBW, it is considered as non-overlapping.

[0064] At this time, the data information to be recorded and paid attention to is added to PhaseNoiseIndexList (index is the length of PhaseNoiseList + 1, freq is , rbw is ), then record the phase noise point data of the second range of SI in FFTList to the phase noise table, and enter the next iterative calculation loop. The second range is SignalIndex+1 to SignalIndex+a* / .

[0065] Step S300 sets the ADC chip operating frequency to F, reads data to establish a frequency data table NFFTList, obtains the index value NSI corresponding to the input signal frequency point, and records the phase noise point data of the measurement frequency range covered by NSI into the phase noise table.

[0066] Specifically, after a series of iterative operations are completed in step S200, the operating frequency of the ADC chip is set to F (Hz). At this time, the data is read and named NDataList. The data length is NS, which is equal to F divided by RBW. Then, Fourier transform is applied to NDataList to obtain the frequency data table NFFTList, which defines the data length as NFS, which is equal to NS divided by 2.

[0067] After that, the input signal frequency point is retrieved in NFFTList to obtain the index value NSI (i.e. NSignalIndex) corresponding to the input signal frequency point; then, according to NFFTList, RBW, and NSignalIndex, the data information of the measurement frequency range of interest is first recorded and added to PhaseNoiseIndexList. For example, if the RBW ranges to 10MHz, this step is a small loop, and the loop variable is defined as m. The starting condition is m=RBW, and the ending condition is that m is less than or equal to 10M(10*( )), each loop m is multiplied by 10 (index is the length of PhaseNoiseList + m + 1, freq is , rbw is RBW). Then extract RBW to 10MHz (10*( )) and records the phase noise data into PhaseNoiseList.

[0068] Of course, if you want to extract data information of other measurement frequency ranges of interest and add them to PhaseNoiseIndexList, then extract NSI+1 to NSI+a*(10* ) / RBW range to adjust the measurement frequency range of interest, where a is the frequency Hz adjustment parameter and a>0.

[0069] In step S400 , a corresponding value is obtained from a phase noise table according to the measurement frequency, and the corresponding phase noise PN (ie, Phase Noise) is calculated.

[0070] Specifically, the first data in PhaseNosieList is replaced with the signal data in NFFTList. Signal and fund are calculated using NFFTList. In an optional embodiment, to smooth the data and ensure data continuity, a Gaussian filter can be applied to PhaseNosieList to obtain GaussFilterList (GaussFilterList and PhaseNosieList have the same length), and the phase noise data is calculated using GaussFilterList.

[0071] Finally, calculate the formula: PN = value-10*log10(rbw)-fund to obtain the corresponding phase noise PN.

[0072] Where value is the data in GaussFilterList (or the data in PhaseNosieList if no Gaussian filtering is performed), rbw refers to the value corresponding to rbw in PhaseNoiseIndexList, fund is the fundamental signal value (unit: dBFS): fund=20-log10(signal / (2^(ADC bit number-1))), and signal is the input signal value in NFFTList.

[0073] For example, if the fundamental signal value fund is -0.01933dBFS and the frequency is 100kHz (100000Hz), the value is -124.933979. The corresponding rbw is 100, then the corresponding phase noise is PhaseNoise(100kHz) = -124.933979-10*log10(100)-(-0.01933) = -144.914649. The corresponding print information is "The phase noise at frequency 100000 (Hz) is: -144.914649".

[0074] In summary, the phase noise measurement method based on spectrum analysis provided by the present invention can obtain the expected RBW in each iteration process. Therefore, this method requires the use of an ADC chip. Under this premise, the spectrum analysis method can be applied to measure the phase noise at any frequency.

[0075] In addition, although some examples in the present invention describe phase noise measurement with frequencies of interest of 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, or up to 10 MHz, if any other frequency needs to be considered and calculated, the present invention adjusts the calculated frequency Hz by defining a, i.e., a is the frequency Hz adjustment parameter and a>0.

[0076] For example, in the algorithm, RBW= Adjust to RBW= a* , in the iterative process = , changes to =a* , and use the logarithmic base conversion formula (loga(N)=log10(N) / log10(a)). When a=5, RBW is 5*( ), in the iterative process Each time it is 5, 50, 500...

[0077] As can be seen, the conditions for each iteration are essentially changes in the RBW, starting with 1Hz, then 10Hz, 100Hz, 1kHz, and so on. Theoretically, this algorithm can cover all RBWs (1Hz, 10Hz, 100Hz, 1kHz, 10kHz, 100kHz, 1MHz, 10MHz, 100MHz, and even 1GHz). However, in reality, ADC chips perform best at a specified operating frequency (the known condition F in the algorithm). Therefore, this algorithm focuses on data at operating frequency F. During the algorithm, data at multiple input signal frequency points is obtained, and the data ultimately used for calculations should be based on the data at operating frequency F. Assuming that the ADC's RBW at operating frequency F in the algorithm is 1kHz, then, in non-extreme cases, the iteration can be exited after the first iteration completes (that is, the amount of data after the input signal index is greater than or equal to 1000).

[0078] Therefore, with the solution of the present invention, the resolution bandwidth is set by the ADC chip during each iteration, allowing the resolution bandwidth to reach, for example, 1 Hz (first iteration), 10 Hz (second iteration, if necessary), 100 Hz (third iteration, if necessary), etc. This ensures that low-frequency spectrum data (e.g., 1 Hz to 100 Hz) can be obtained. Thus, in the final phase noise calculation, the input data (spectral data at the corresponding frequencies) required for the phase noise value can be directly measured.

[0079] On the other hand, corresponding to the above method, reference Figure 2As shown, the present invention also provides a phase noise measurement system based on spectrum analysis, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of the phase noise measurement method based on spectrum analysis as described in any of the above examples.

[0080] On the other hand, corresponding to the above method, the present invention also provides a computer-readable storage medium, which stores a computer program, wherein when the computer program is executed, the steps of the phase noise measurement method based on spectrum analysis as described in any of the above examples are implemented.

[0081] In summary, the spectrum analysis-based phase noise measurement method, system, and storage medium provided by the present invention cleverly design an iterative algorithm based on spectrum analysis. During each iteration, the ADC chip sets the resolution bandwidth, ensuring that the resolution bandwidth reaches the desired low-frequency region. This ensures that the required low-frequency spectrum data can be obtained for calculating the corresponding phase noise. This effectively solves the problem of traditional methods that cannot directly measure phase noise at low frequencies due to RBW limitations.

[0082] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made based on the contents of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0083] Those skilled in the art will understand that, in addition to implementing the systems, devices, units, and their respective modules provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same programs in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. by logically programming the method steps. Therefore, the systems, devices, and their respective modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0084] In addition, all or part of the steps in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a program. The program is stored in a storage medium and includes a number of instructions for causing a single-chip microcomputer, chip, or processor to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., various media that can store program code.

[0085] In addition, various implementations of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A phase noise measurement method based on spectrum analysis, the steps including: Determine the resolution bandwidth RBW according to the maximum data length S that can be processed currently and the operating frequency F of the ADC chip; Iterative calculation is performed according to the preset iteration condition N, including: Under current conditions and ADC operating frequency ; The preset iteration condition N is: The initial condition is N = 0, the termination condition is N < P, and N is incremented by 1 each time, where P = ceil(log10(F / S)); in and The calculation steps include: calculate = a* ; calculate = *S; where a is a frequency adjustment parameter in Hz and a > 0; Set the ADC chip operating frequency to , read the data to establish the frequency data table FFTList, and obtain the index value SI corresponding to the input signal frequency point; When it is judged that the data length of the phase noise points in FFTList coincides with RBW, record the phase noise point data in the first range of SI in FFTList into the phase noise table, jump out of the loop, otherwise record the phase noise point data in the second range of SI into the phase noise table and continue the iterative calculation; The first range of the index value SI is: SI+1 to SI+1+RBW / ; The second range of index value SI: SI+1 to SI+a* / ; Where a is the frequency Hz adjustment parameter and a>0; The step of determining whether the phase noise point data length of FFTList coincides with RBW includes: calculating the phase noise point data length PNDataLength = FS-SI-1; where FS is half of the maximum data length S that can be processed currently; and only when PNDataLength* ≥ RBW, it is determined that PNDataLength coincides with RBW; Set the ADC chip operating frequency to F, read the data to establish the frequency data table NFFTList, and obtain the index value NSI corresponding to the input signal frequency point; record the phase noise point data of the measurement frequency range covered by NSI in the phase noise table; the measurement frequency range covered by the index value NSI is: NSI+1 to NSI+a*(10* ) / RBW, where a is the frequency Hz adjustment parameter and a>0; Set up a phase noise index table to record the data index, measurement frequency freq, and resolution bandwidth rbw corresponding to the phase noise point data value in the phase noise table; Calculate the corresponding phase noise according to the value index of the phase noise index table, the steps including: obtain the corresponding value from the phase noise table according to the measurement frequency, and calculate the corresponding phase noise PN = value - 10*log10(rbw) - fund, where fund is the fundamental wave signal value.

2. The phase noise measurement method based on spectrum analysis according to claim 1, wherein the step of determining the resolution bandwidth RBW includes: Calculate RBW = a* , where P = ceil(log10(F / S)), a is the frequency Hz adjustment parameter and a>

0.

3. A phase noise measurement system based on spectrum analysis, comprising: Comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of the phase noise measurement method based on spectrum analysis according to any one of claims 1 to 2.

4. A computer-readable storage medium storing a computer program, wherein when the computer program is executed, the steps of the phase noise measurement method based on spectrum analysis according to any one of claims 1 to 2 are implemented.

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