Clock signal sinusoidal jitter calculation method, computer device and readable storage medium

Abstract

The application provides a clock signal sinusoidal jitter calculation method, a computer device and a readable storage medium. The method comprises the following steps: obtaining frequency spectrum information of a to-be-tested clock signal injected with a sinusoidal jitter signal; identifying a plurality of target frequency points in the frequency spectrum information of the to-be-tested clock signal with a period of the sinusoidal jitter signal as a time interval, and determining amplitudes of the to-be-tested clock signal at the target frequency points; determining orders of the target frequency points according to the amplitudes of the to-be-tested clock signal at the target frequency points, and calculating an amplitude of the sinusoidal jitter signal by using the amplitudes corresponding to the target frequency points of each order based on a preset target function. The application also provides a computer device and a readable storage medium for implementing the above method. The application can reduce the amplitude calculation cost of the sinusoidal jitter signal and improve the accuracy of the amplitude calculation of the sinusoidal jitter signal.

Description

Technical Field

[0001] This invention relates to the technical field of clock data processing, specifically to a method for calculating the sinusoidal jitter of a clock signal, and a computer device and computer-readable storage medium for implementing this method. Background Technology

[0002] In high-speed serial communication systems, clock signals often contain various jitter signals. Common jitter signals include periodic jitter signals, among which sinusoidal jitter signals are a common type of periodic jitter signal.

[0003] During chip testing, it is often necessary to test the chip's ability to eliminate jitter signals in the clock signal. To do this, a sinusoidal jitter signal needs to be added to the clock signal being tested. Therefore, the clock signal with the injected sinusoidal jitter signal needs to be detected to determine whether the injected sinusoidal jitter signal meets the preset requirements.

[0004] Currently, the common methods for detecting sinusoidal jitter signals in clock signals mainly include the following:

[0005] First, a real-time oscilloscope is used to acquire the clock signal waveform, and the time interval error is statistically analyzed. The calculated change in the time interval error is the amplitude of the sinusoidal jitter signal, and the frequency of the time interval error change is the frequency of the sinusoidal jitter signal. While this detection method offers high accuracy, it requires a high sampling depth to capture sufficient trend data when measuring low-frequency, high-amplitude sinusoidal jitter signals, and the testing time is relatively slow. Furthermore, real-time oscilloscopes and accompanying analysis software that meet the corresponding testing requirements are expensive, and testers need extensive training to master the relevant testing techniques.

[0006] Second, using a sampling oscilloscope to directly measure the period jitter of the clock signal is acceptable in scenarios involving the measurement of high-frequency, small-amplitude sinusoidal jitter signals. However, since it can only be used when the built-in clock recovery lock is engaged, if the clock recovery bandwidth is too high, it will track low-frequency jitter, resulting in the inability to measure the sinusoidal jitter signal. If the clock recovery bandwidth is too low, it will be unable to lock the sinusoidal jitter signal being measured. Furthermore, the instruments used are relatively expensive.

[0007] Third, a phase noise meter is used to count the spurious signal energy within the clock signal integration range, calculate the jitter value corresponding to each spur, and then calculate the amplitude of the sinusoidal jitter signal. However, since this method can only analyze the jitter amplitude of each independent spur, it performs reasonably well in measuring high-frequency, small-amplitude sinusoidal jitter signals. But when measuring low-frequency, large-amplitude sinusoidal jitter signals, due to the large number of spurious components, long time intervals, and dispersed energy, the integration range needs to be set very large, making it impossible to accurately measure the amplitude of the sinusoidal jitter signal.

[0008] Overall, current methods for calculating sinusoidal jitter are based on time-domain analysis. Both data analysis and data collection require the acquisition of actual waveforms, which generally suffers from problems such as high software costs and insufficient accuracy in analyzing low-frequency signals. Summary of the Invention

[0009] The primary objective of this invention is to provide a method for calculating the sinusoidal jitter of a clock signal that is both computationally cost-effective and highly accurate.

[0010] A second objective of the present invention is to provide a computer device for implementing the above-described clock signal sine jitter calculation method.

[0011] A third objective of this invention is to provide a readable storage medium for implementing the above-described clock signal sine jitter calculation method.

[0012] To achieve the first objective of this invention, the clock signal sinusoidal jitter calculation method provided by this invention includes acquiring the spectral information of a clock signal under test injected with a sinusoidal jitter signal, identifying multiple target frequency points in the spectral information of the clock signal under test with the period of the sinusoidal jitter signal as the time interval, and determining the amplitude of the clock signal under test at each target frequency point; determining the order of each target frequency point based on the amplitude of the clock signal under test at each target frequency point, and calculating the amplitude of the sinusoidal jitter signal using the amplitude corresponding to each target frequency point based on a pre-set objective function.

[0013] As can be seen from the above scheme, this invention acquires the spectral information of the clock signal under test, identifies the order of each target frequency point, and substitutes the amplitude of each target frequency point into the objective function for calculation. The amplitude of the sinusoidal jitter signal is then calculated iteratively. The entire calculation process is based on frequency domain analysis and calculation, eliminating the need for expensive instruments or complex software.

[0014] In addition, the present invention uses a preset objective function to calculate the amplitude of the sinusoidal jitter signal based on the amplitude of each order. Through multiple iterations, the amplitude of the sinusoidal jitter signal can be calculated more accurately.

[0015] A preferred approach is to calculate the amplitude of the sinusoidal jitter signal based on the amplitude corresponding to each target frequency point using a pre-defined objective function, while also calculating the fundamental amplitude of the clock signal under test.

[0016] Therefore, it can be seen that while calculating the amplitude of the sinusoidal jitter signal, it can also calculate the basic amplitude of the clock signal under test, and judge whether the basic amplitude of the clock signal under test meets the preset requirements.

[0017] A preferred approach is to calculate the amplitude of the sinusoidal jitter signal based on the amplitude corresponding to each target frequency point using a pre-defined objective function. This includes substituting the amplitude corresponding to each target frequency point into the objective function and iteratively calculating the basic amplitude of the clock signal under test and the amplitude of the sinusoidal jitter signal.

[0018] Therefore, it is evident that by substituting the amplitudes corresponding to each target frequency point into the objective function to calculate the basic amplitude of the clock signal under test and the amplitude of the sinusoidal jitter signal, the results of iterative calculation are more accurate when there are a large number of target frequency points.

[0019] A further proposed approach is to define the objective function as follows: ,in, It is the amplitude corresponding to the nth frequency point of the clock signal under test. It is the fundamental amplitude of the clock signal under test. It is the amplitude of the sinusoidal jitter signal. It is a multi-order Bessel function.

[0020] Therefore, it can be seen that since the objective function is not complicated and the amount of calculation is small, it can quickly and accurately calculate the basic amplitude of the clock signal under test and the amplitude of the sinusoidal jitter signal.

[0021] A further approach involves obtaining the spectral information of the clock signal under test injected with a sinusoidal jitter signal, which includes: acquiring the clock signal under test, inputting the clock signal under test into a spectrum analyzer, and using the spectrum analyzer to obtain the spectral information of the clock signal under test.

[0022] A further approach is to use a spectrum analyzer as the spectrum detection instrument; when using the spectrum analyzer to detect the spectrum information of the clock signal under test, the preset parameters of the spectrum analyzer are adjusted.

[0023] Therefore, it can be seen that the spectrum information of the clock signal under test can be obtained directly through a regular spectrum analyzer without the need for complex software support, and the amplitude of the sinusoidal jitter signal can be calculated at low cost.

[0024] A further approach is to preset parameters including intermediate frequency bandwidth and / or resolution bandwidth. This allows for better adaptation to the detection requirements of clock signals at different frequencies by optimizing the intermediate frequency bandwidth and resolution bandwidth parameters.

[0025] An alternative approach is to use an oscilloscope as the spectrum testing instrument. When using an oscilloscope to test the spectrum information of the clock signal under test, the waveform acquired by the oscilloscope is then subjected to a Fourier transform to obtain the spectrum information of the clock signal under test.

[0026] Therefore, it can be seen that by using a regular oscilloscope to acquire the waveform of the clock signal under test and then performing a Fourier transform, the spectral information of the clock signal under test can be obtained. This provides a simple and quick way to obtain the spectral information of the clock signal under test.

[0027] To achieve the second objective described above, the computer device provided by the present invention includes a processor and a memory. The memory stores a computer program, and when the computer program is executed by the processor, it implements each step of the above-described clock signal sine jitter calculation method.

[0028] To achieve the third objective mentioned above, the storage medium provided by the present invention stores a computer program, which, when executed by a processor, implements each step of the above-mentioned clock signal sine jitter calculation method. Attached Figure Description

[0029] Figure 1 This is a spectrum diagram of the clock signal under test in an embodiment of the clock signal sinusoidal jitter calculation method of the present invention.

[0030] Figure 2 This is a flowchart of an embodiment of the clock signal sine jitter calculation method of the present invention.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0032] The clock signal sinusoidal jitter calculation method of the present invention is used to calculate whether the amplitude of a periodic sinusoidal jitter signal injected into a clock signal meets a preset requirement, achieving high-precision calculation in a low-cost manner. The method of the present invention can be implemented on a computer device having a processor and a memory, the memory being a readable storage medium of the present invention, storing a computer program, which, when executed by the processor, comprises the various steps of the aforementioned clock signal sinusoidal jitter calculation method.

[0033] Example of clock signal sine jitter calculation method:

[0034] During chip testing, a base clock signal is first constructed. This base clock signal can be understood as a relatively ideal clock signal, i.e., a clock signal without injected sinusoidal jitter. For testing purposes, a sinusoidal jitter signal is injected into the base clock signal, thus forming the clock signal under test (DUT). Therefore, the DUT is a clock signal injected with a sinusoidal jitter signal. Since the preset values ​​of the frequency and amplitude of the base clock signal, and the preset values ​​of the frequency and amplitude of the injected sinusoidal jitter signal, this embodiment needs to analyze the actual DUT to determine whether the amplitude of the base clock signal and the amplitude of the sinusoidal jitter signal in the actual DUT are the same as the preset values, thereby determining whether the injected sinusoidal jitter signal is accurate.

[0035] Injecting a sinusoidal jitter signal into the base clock signal essentially modulates the phase of the base clock signal. The base clock signal injected with the sinusoidal jitter signal can be represented by the following formula:

[0036] (Equation 1),

[0037] Among them, It is the amplitude of the fundamental clock signal, that is, the fundamental amplitude of the clock signal under test. It is the frequency of the fundamental clock signal, that is, the fundamental frequency of the clock signal under test. It is the amplitude of the sinusoidal jitter signal, and its unit is UI, which is one time interval. It is the frequency of the sinusoidal dithering signal.

[0038] By performing a Bezier expansion on Equation 1, we obtain the following formula:

[0039] (Equation 2),

[0040] in, It is an nth-order Bessel function. Therefore, the spectrum of the clock signal under test after adding a sinusoidal jitter signal is a combination of the base clock signal frequency and a single-frequency signal of a sinusoidal jitter signal frequency that is n times the base clock signal frequency. The signal amplitude at each frequency point can be expressed by the following formula:

[0041] (Equation 3).

[0042] Therefore, the frequency diagram of the clock signal under test is as follows: Figure 1 As shown. The amplitude is largest at the 0th order frequency. Figure 1The waveform of the 0th-order frequency signal is represented by number 21. Other frequency bands are symmetrically distributed around the 0th-order frequency signal. For example, the -1st-order frequency signal 22 and the 1st-order frequency signal 25 are symmetrically distributed on either side of the 0th-order frequency signal 21; the -2nd-order frequency signal 23 and the 2nd-order frequency signal 26 are symmetrically distributed on either side of the 0th-order frequency signal 21; the -3rd-order frequency signal 24 and the 3rd-order frequency signal 27 are symmetrically distributed on either side of the 0th-order frequency signal 21, and so on. Furthermore, as the absolute value of the order increases, the amplitude of each frequency signal gradually decreases. Therefore, by measuring the amplitude of each frequency signal and combining it with Formula 3, the fundamental amplitude of the clock signal under test can be obtained. and the amplitude of the injected sinusoidal dithering signal The value of the clock signal under test is calculated based on the above principle. This embodiment calculates the fundamental amplitude of the clock signal under test. and the amplitude of the injected sinusoidal dithering signal The value of .

[0043] See Figure 2 In this embodiment, step S11 is first executed to acquire the clock signal to be tested. Specifically, the clock signal to be tested is detected by a signal acquisition circuit. Typically, the clock signal to be tested is an analog signal, and the signal acquisition circuit is a circuit that acquires analog signals.

[0044] Then, step S12 is executed, whereby the acquired clock signal under test is input to the spectrum detection instrument to obtain the spectrum information of the clock signal under test, such as obtaining... Figure 1 The spectrum diagram shown is illustrated. Specifically, the spectrum detection instrument can be a regular spectrum analyzer, which directly measures the amplitude of the signal at each frequency point. Furthermore, to more accurately calculate each frequency point and its amplitude, the preset parameters of the spectrum analyzer need to be adjusted. These preset parameters include the intermediate frequency bandwidth and the resolution bandwidth. Depending on the actual needs, both the intermediate frequency bandwidth and the resolution bandwidth can be adjusted simultaneously, or only one of them can be adjusted to meet the detection requirements of the clock signal under test at different frequencies.

[0045] In another embodiment, the spectrum detection instrument can be an oscilloscope. When using an oscilloscope to detect the spectrum information of the clock signal under test, firstly, the waveform acquired by the oscilloscope needs to be obtained. Then, a Fourier transform is performed on the acquired waveform to obtain the spectrum information of the clock signal under test, i.e., to obtain... Figure 1 The spectrum diagram shown is an example of this method. In this way, a regular oscilloscope can be used to obtain the waveform of the clock signal under test. The calculation of the Fourier transform of the waveform is not complex and can be performed without complex software, providing a simple and quick way to obtain the spectral information of the clock signal under test.

[0046] Next, step S13 is executed to analyze multiple target frequency points in the clock signal under test. Specifically, a signal with a very high amplitude will be generated at the target frequency point. Therefore, multiple target frequency points can be analyzed by identifying the amplitude in the spectrum. Furthermore, by identifying the point with the maximum amplitude in the spectrum as the 0th-order frequency signal, frequency points of various orders are identified sequentially to the left and right of the 0th-order frequency signal. For example, the -1st-order frequency signal and the 1st-order frequency signal are identified. Then, the -2nd-order frequency signal is identified to the left of the -1st-order frequency signal, the 2nd-order frequency signal is identified to the right of the 1st-order frequency signal, and so on.

[0047] After identifying multiple target frequencies, step S14 is executed to obtain the amplitude of the clock signal under test at each target frequency. The order of each target frequency is determined based on its amplitude. Since the 0th-order frequency signal has the largest amplitude, while the amplitudes of the -1st and 1st-order frequency signals are smaller than those of the 0th-order frequency signal, and theoretically, the frequency interval between two adjacent target frequency signals should be the frequency period of a sinusoidal jitter signal, the order of each frequency point in the spectrum can be quickly determined according to these rules. Furthermore, the amplitude of each order frequency signal is identified and denoted as... ,Right now It is the amplitude of the nth frequency point signal. For example, the amplitude of the 0th frequency point signal is denoted as A0, and the amplitude of the -1st frequency point signal is denoted as A... -1 And so on.

[0048] Finally, step S15 is executed, inputting the amplitudes corresponding to multiple target frequency signals into the objective function, and calculating the fundamental amplitude of the clock signal under test and the amplitude of the sinusoidal jitter signal. Based on the principles described above, the objective function in this embodiment is expressed by the following formula:

[0049] (Equation 4)

[0050] in, It is the amplitude corresponding to the nth frequency point of the clock signal under test. It is the fundamental amplitude of the clock signal under test. It is the amplitude of the sinusoidal jitter signal. It is a Bessel function.

[0051] By collecting amplitude values ​​at multiple target frequency points and performing iterative calculations, the fundamental amplitude of the clock signal under test can be calculated. The amplitude of the sinusoidal jitter signal For example, the `optimize.minimize` function from the Python SciPy database can be used for iterative calculations. This calculation method involves determining Formula 4 above and obtaining the amplitude of the signal at each frequency point. Then, given a set of initial parameter guesses, the algorithm iterates through multiple calculations to reduce the error between the function value obtained from the current guesses and the actual function value, ultimately obtaining the solution with the smallest error, thereby calculating the fundamental amplitude of the clock signal under test. The amplitude of the sinusoidal jitter signal .

[0052] Therefore, this embodiment calculates the fundamental amplitude of the clock signal under test based on the frequency domain. The amplitude of the sinusoidal jitter signal Instead of performing analysis and calculations based on the time domain, once the spectral information of the clock signal under test is obtained, the target frequencies at each order can be obtained through simple methods, and the amplitude corresponding to each target frequency can be acquired. Then, based on the objective function, the fundamental amplitude of the clock signal under test can be quickly and accurately calculated through iterative calculation. The amplitude of the sinusoidal jitter signal Since the spectral information of the clock signal under test can be obtained using a common spectrum analyzer or oscilloscope, and the cost is no less than using expensive software, the amplitude calculation of the jitter signal is low-cost, and the fundamental amplitude of the clock signal under test can be accurately obtained through multiple iterative calculations. The amplitude of the sinusoidal jitter signal .

[0053] Computer device embodiment:

[0054] The computer device in this embodiment can be various types of computer devices, such as desktop computers, laptops, data processing servers, etc. The computer device has a processor, a memory, and a computer program stored in the memory and executable on the processor, such as an information processing program for implementing the above-described information processing method. When the processor executes the computer program, it implements each step of the above-described clock signal sine jitter calculation method.

[0055] For example, a computer program can be divided into one or more modules, one or more of which are stored in memory and executed by a processor to complete the various modules of the present invention. One or more modules can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a terminal device.

[0056] The processor referred to in this invention can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting various parts of the terminal device through various interfaces and lines.

[0057] Memory can be used to store computer programs and / or modules. The processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function, etc.; the data storage area may store data created based on the use of the mobile phone, etc. In addition, memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0058] Storage medium examples:

[0059] If a computer program stored in a computer device is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the various steps of the above-described clock signal sine jitter calculation method.

[0060] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in computer-readable media can be appropriately added to or subtracted according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0061] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of calculating sinusoidal jitter of a clock signal, characterized by, The method comprises: obtaining spectrum information of a to-be-tested clock signal injected with a sinusoidal jitter signal, identifying a plurality of target frequency points in the spectrum information of the to-be-tested clock signal with a period of the sinusoidal jitter signal as a time interval, and determining amplitudes of the to-be-tested clock signal at each target frequency point; determining orders of each target frequency point according to the amplitudes of the to-be-tested clock signal at each target frequency point, and calculating an amplitude of the sinusoidal jitter signal based on a preset target function and the amplitudes corresponding to each order target frequency point. The target function is: ， wherein, is the amplitude of the nth order frequency point of the clock signal to be measured, is the basic amplitude of the clock signal to be measured, is the amplitude of the sinusoidal jitter signal, is a multi-order Bessel function.

2. The method according to claim 1, wherein: when calculating the amplitude of the sinusoidal jitter signal based on the preset target function and the amplitudes corresponding to each order target frequency point, the basic amplitude of the to-be-tested clock signal is also calculated.

3. The method of claim 2, wherein, The method further comprises: calculating the amplitude of the sinusoidal jitter signal based on the preset target function and the amplitudes corresponding to each order target frequency point comprises: substituting the amplitudes corresponding to each order target frequency point into the target function, and iteratively calculating the basic amplitude of the to-be-tested clock signal and the amplitude of the sinusoidal jitter signal.

4. The method according to any one of claims 1 to 3, wherein: obtaining the spectrum information of the to-be-tested clock signal injected with the sinusoidal jitter signal comprises: obtaining the to-be-tested clock signal, inputting the to-be-tested clock signal into a spectrum detection instrument, and applying the spectrum detection instrument to obtain the spectrum information of the to-be-tested clock signal.

5. The method according to claim 4, wherein: the spectrum detection instrument is a spectrum analyzer; when applying the spectrum analyzer to detect the spectrum information of the to-be-tested clock signal, a preset parameter of the spectrum analyzer is adjusted.

6. The method according to claim 5, wherein: the preset parameter comprises an intermediate frequency bandwidth and / or a resolution bandwidth.

7. The method according to claim 4, wherein: the spectrum detection instrument comprises an oscilloscope; when applying the oscilloscope to detect the spectrum information of the to-be-tested clock signal, a waveform obtained by the oscilloscope is subjected to Fourier transform to obtain the spectrum information of the to-be-tested clock signal.

8. Computer means, characterized in that The method comprises a processor and a memory, the memory stores a computer program, and the computer program is executed by the processor to implement each step of the clock signal sinusoidal jitter calculation method according to any one of claims 1 to 7.

9. A readable storage medium having stored thereon a computer program, characterized in that: The computer program is executed by the processor to implement each step of the clock signal sinusoidal jitter calculation method according to any one of claims 1 to 7.

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