Electromagnetic interference analysis methods and apparatus for chips, electronic equipment

Abstract

This application relates to the field of chip design technology, providing a method, apparatus, and electronic device for electromagnetic interference (EMI) analysis of chips. The method includes: loading an excitation signal onto a simulation module during chip design verification, causing the simulation module to generate an output signal based on the chip's circuit structure; performing time-frequency analysis on the output signal to obtain its spectral information; and determining whether the chip meets predetermined EMI requirements based on the spectral information. This application enables EMI analysis during the chip design phase, which helps reduce EMI problems and thus lowers the design cost of electronic products. Furthermore, this application can modify the chip design based on the spectral information and a periodic code extracted from the time-domain information, thereby ensuring the chip meets predetermined EMI requirements.

Description

[0001] This application is a divisional application of application number "202211373429.6", filed on "November 4, 2022", entitled "Method and apparatus for electromagnetic interference analysis of chips and electronic equipment". Technical Field

[0002] This application relates to the field of chip design technology, and in particular to methods and apparatus for analyzing electromagnetic interference in chips, as well as electronic equipment. Background Technology

[0003] Each country has its own limits on electromagnetic interference (EMI) for electronic products, and only electronic products that meet these limits can be sold locally. Therefore, chips in electronic products need to undergo EMI analysis before being released to the market.

[0004] In existing technologies, chips are typically installed after the circuit board design is completed, followed by electromagnetic interference (EMI) testing. If EMI problems are found, they are then addressed at the board or system level. The earlier EMI issues are considered and resolved, the lower the cost, the better the results, and the lower the overall cost. Chips, especially high-speed digital chips, are often the source of EMI. Identifying and analyzing EMI problems early in the chip design process and suppressing them can significantly reduce product design costs and delivery cycles, while also improving product reliability.

[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0006] The limitations of existing electromagnetic interference (EMI) analysis are that EMI problems can only be detected after chip manufacturing is completed, and cannot be detected during the chip design stage. Therefore, EMI problems often need to be solved at the board level or system level, which increases product costs. For example, adding grounding, shielding, and filtering methods increases costs. In addition, severe EMI problems may cause board washing, which delays product delivery and further increases costs.

[0007] To address at least the aforementioned technical problems or similar technical issues, embodiments of this application provide an electromagnetic interference (EMI) analysis method, apparatus, and electronic device for chips. In this EMI analysis method, during the chip design phase, an excitation signal is input to the chip's simulation module to generate an output signal. Time-frequency analysis is then performed on this output signal, and the results are used to determine whether the chip meets predetermined EMI requirements. Therefore, EMI analysis can be performed during the chip design phase, which helps reduce EMI problems during chip design and thus lowers the design cost of electronic products.

[0008] This application provides a method for analyzing electromagnetic interference (EMI) of a chip, the method comprising:

[0009] An excitation signal is input to the simulation module during chip design verification, causing the simulation module to generate an output signal based on the circuit structure of the chip;

[0010] Perform time-frequency analysis on the output signal to obtain the spectrum information of the output signal; and

[0011] Based on the spectrum information, determine whether the chip meets the predetermined electromagnetic interference (EMI) requirements.

[0012] This application also provides an electromagnetic interference analysis device for a chip, the device comprising:

[0013] An excitation signal input unit inputs an excitation signal to the simulation module of the chip, causing the simulation module to generate an output signal based on the circuit structure of the chip;

[0014] A time-frequency analysis unit performs time-frequency analysis on the output signal to obtain the spectrum information of the output signal; and

[0015] The judgment unit determines whether the chip meets the predetermined electromagnetic interference (EMI) requirements based on the spectrum information.

[0016] The beneficial effects of the embodiments of this application are that electromagnetic interference analysis can be performed during the chip design stage, which helps to reduce electromagnetic interference problems during the chip design stage, thereby reducing the design cost of electronic products.

[0017] Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of this application can be adopted. It should be understood that the embodiments of this application are not limited in scope. Within the scope of the appended claims, embodiments of this application include many changes, modifications, and equivalents.

[0018] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0019] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0021] Figure 1 This is a schematic diagram of the electromagnetic interference analysis method for the chip in this application;

[0022] Figure 2 This is a schematic diagram of a method for extracting periodic codes from an output signal;

[0023] Figure 3 This is a schematic diagram of the Fourier transform result of the output signal generated by the C / A line of the graphics card's GDDR6;

[0024] Figure 4 This is a schematic diagram of the result of performing another Fourier transform on the output signal;

[0025] Figure 5 This is a schematic diagram of the electromagnetic interference analysis device for the chip in this application;

[0026] Figure 6 This is a schematic diagram of an electronic device. Detailed Implementation

[0027] Referring to the accompanying drawings, the foregoing and other features of this application will become apparent from the following description. Specific embodiments of this application are specifically disclosed in the description and drawings, illustrating partial implementations in which the principles of this application can be adopted. It should be understood that this application is not limited to the described embodiments; rather, it includes all modifications, variations, and equivalents falling within the scope of the appended claims. Various embodiments of this application are described below with reference to the accompanying drawings. These embodiments are merely exemplary and not intended to limit the scope of this application.

[0028] In the embodiments of this application, the terms "first," "second," "upper," "lower," etc., are used to distinguish different elements by their names, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the terms listed in connection with the application and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0029] In the embodiments of this application, the singular forms "a," "the," etc., including the plural forms, should be broadly understood as "a kind" or "a class" rather than limited to the meaning of "an." Furthermore, the term "the" should be understood to include both the singular and plural forms, unless the context explicitly indicates otherwise. Additionally, the term "according to" should be understood as "at least partially based on…," and the term "based on" should be understood as "at least partially based on…," unless the context explicitly indicates otherwise.

[0030] First aspect of the embodiments

[0031] An embodiment of the first aspect of this application provides a method for analyzing electromagnetic interference (EMI) of a chip.

[0032] Figure 1 This is a schematic diagram of the electromagnetic interference analysis method for the chip described in this application. For example... Figure 1 As shown, the analytical method includes:

[0033] Operation 101: Input an excitation signal to the simulation module during chip design verification, so that the simulation module generates an output signal based on the circuit structure of the chip;

[0034] Operation 102: Perform time-frequency analysis on the output signal to obtain its spectrum information; and

[0035] Operation 103: Determine whether the chip meets the predetermined electromagnetic interference requirements based on the spectrum information.

[0036] According to the embodiment of the first aspect, during the chip design and verification phase, an excitation signal is input to the chip's simulation module to generate an output signal. Time-frequency analysis is then performed on this output signal, and the chip's compliance with predetermined electromagnetic interference requirements is determined based on the results of the time-frequency analysis. Therefore, electromagnetic interference analysis can be performed during the chip design phase, which helps reduce electromagnetic interference problems during chip design and thus lowers the design cost of electronic products.

[0037] In this application, the chip simulation module can be implemented by circuit simulation software, which can simulate the chip's operation based on its internal circuit structure. Examples of circuit simulation software include Proteus, PSIM, or Multisim, and other similar software may also be used.

[0038] In operation 101, an excitation signal can be input to the chip interface in the chip's simulation module to analyze the electromagnetic interference caused by that interface. For example, operation 101 can be implemented by loading the corresponding excitation and acquiring data, and then transmitting the data through the register-transfer level (RTL).

[0039] In chips, especially high-speed digital chips, the types of interfaces are constantly increasing, and the data transmission rates of interfaces are also getting higher and higher. Therefore, the interfaces for input excitation signals can be determined based on their data transmission rates. For example, for newly added interfaces with higher data transmission rates in a chip, excitation signals can be input to analyze the electromagnetic interference (EMI) caused by that interface; similarly, if chip upgrades lead to increased data transmission rates for some existing interfaces, these interfaces can also be used as targets for EMI analysis, and excitation signals can be input to these interfaces.

[0040] In operation 101, a data excitation signal can be applied to the interface according to the actual application scenario. This excitation signal may include at least one of the following excitation signals:

[0041] The chip has a built-in self-test stimulus signal, which is set for certain predetermined functions of the chip; a periodic stimulus signal, which can be used to directly simulate the logic bit changes under the worst-case scenario in electromagnetic interference test scenarios; and a random state data stream stimulus signal, which can be used to simulate the logic bit changes of the chip's output signal under random states in daily use scenarios.

[0042] In operation 101, any one of the above-mentioned excitation signals can be input, or any two can be input sequentially. Alternatively, all three excitation signals can be input sequentially, thereby enabling simulation of the output signals corresponding to the interface in various operating modes. Furthermore, this application is not limited to this; the input excitation signals can also be of other types.

[0043] In operation 101, when the simulation module of the chip is given an input excitation signal, the simulation module can generate an output signal and output it from the chip's output terminal. This chip can be, for example, a controller, a graphics processor, or a cache, etc., and this application does not impose any limitations on this. The output signal can be a digital waveform pulse with varying amplitudes at different times, and this digital waveform pulse may contain signal distortions introduced at the circuit level, such as overcharge, undershoot, and jitter.

[0044] In operation 102, time-frequency analysis is performed on the output signal generated in operation 101 to obtain the spectral information of the output signal. This time-frequency analysis is, for example, a Fourier transform, thereby converting the time-domain output signal into the frequency domain. The spectral information of the output signal includes, for example, the power spectral density (PSD) in the frequency domain, which represents the power density of the signal at different frequency points. Furthermore, the spectral information can also be other information reflecting the degree of electromagnetic interference; this application is not limited to power spectral density.

[0045] In operation 103, the spectrum information generated in operation 102 is analyzed to determine whether the chip meets the predetermined electromagnetic interference (EMI) requirements. For example, the power spectral density in the frequency domain obtained by operation 102 can be analyzed to determine whether there are discrete peak frequency radiation points. If there are no discrete peak frequency radiation points, the chip is judged to meet the predetermined electromagnetic interference requirements. If there are discrete peak frequency radiation points, the discrete peak frequency radiation points can be further analyzed. For example, the amplitude (i.e., power density) of the discrete peak frequency radiation points can be compared with the spectrum information of the output signal of the previous generation chip. If the amplitude is lower than or equal to the amplitude of the same frequency radiation point in the spectrum information of the output signal of the previous generation chip, the chip is judged to meet the predetermined electromagnetic interference requirements. Otherwise, the chip is judged not to meet the predetermined electromagnetic interference requirements. Alternatively, the amplitude (i.e., power density) of the discrete peak frequency radiation points can be compared with a preset threshold. If the amplitude is lower than or equal to the preset threshold, the chip is judged to meet the predetermined electromagnetic interference requirements. Otherwise, the chip is judged not to meet the predetermined electromagnetic interference requirements.

[0046] In at least one embodiment, such as Figure 1 As shown, the electromagnetic interference analysis method for this chip also includes:

[0047] Operation 104: If it is determined that the chip does not meet the predetermined electromagnetic interference requirements, extract the periodic bit pattern from the output signal.

[0048] In digital chips, periodic bit patterns in digital signals can generate electromagnetic interference with high power density. Therefore, in operation 104 of this application, periodic bit patterns are extracted from the output signal to identify the main factors generating electromagnetic interference in the output signal.

[0049] A code pattern refers to the combination of data bits in a signal. For example, if the data bits (i.e., the data stream) in a signal are 01010101, where 0 and 1 appear periodically, then this signal has a periodic code pattern. Another example is a signal with data bits of xy01xy01xy01xy01, where x is either 0 or 1, y is either 0 or 1, and xy01 appears periodically; therefore, this signal also has a periodic code pattern. Yet another example is a signal with data bits of 001000101110, where there is no periodic code stream, therefore, this signal does not have a periodic code pattern.

[0050] In at least one embodiment, such as Figure 1 As shown, the electromagnetic interference analysis method for this chip also includes:

[0051] Operation 105: Based on the extracted periodic code pattern, modify the design scheme of the chip.

[0052] In operation 105, the factors in the chip design that cause the periodic code pattern extracted in operation 104 can be determined. For example, for this periodic code pattern, the discrete peak frequency radiation points obtained in operation 102 and / or the operating protocols of the interfaces involved in operation 101 can be combined to determine which periodic code pattern(s) is the cause of electromagnetic interference. In one specific embodiment, a database can be constructed that stores the correspondence between different periodic code patterns, discrete peak frequency radiation points, and / or interface operating protocols. Based on this correspondence, the periodic code pattern causing electromagnetic interference can be determined.

[0053] In operation 105, after identifying the periodic code pattern causing electromagnetic interference, the chip design can be modified to disrupt the periodic characteristics of the code pattern. The chip design includes: the chip's interface operating protocol, and / or the chip's circuit structure, and / or the chip's clock characteristics, etc.

[0054] In operation 105, modifying the chip design may include at least one of the following methods: modifying the circuit structure or interface operating protocol to prevent or destroy periodic patterns, such as flipping bits in the signal promptly after detecting the appearance of a periodic pattern causing electromagnetic interference, thereby destroying the periodicity of the pattern; scrambling a certain length of output signal to make it exhibit white noise characteristics in the frequency domain, wherein the scrambling method can refer to relevant technologies; and performing spectral spreading processing on the chip's reference clock based on spread spectrum clock (SSC) technology, so that the spectral energy of the output signal is not concentrated on certain peaks. In one specific embodiment, a database can be constructed to store the correspondence between different periodic patterns, different interfaces, and the modification methods of the chip design. Based on this correspondence, it is possible to determine what modifications to the chip design.

[0055] The modified chip design, implemented in operation 105, will cause corresponding modifications to the chip's simulation module. The modified simulation module will then be re-inputted with an excitation signal; that is, operations 101, 102, and 103 will be performed again. If the chip still does not meet the predetermined electromagnetic interference requirements, operations 104 and 105 will be performed again. Thus, through the electromagnetic interference analysis method of this application, the chip can meet the predetermined electromagnetic interference requirements.

[0056] Figure 2 This is a schematic diagram illustrating a method for extracting periodic codes from the output signal, used to implement operation 104. For example... Figure 2 As shown, methods for extracting periodic codes from output signals include:

[0057] Operation 201: Shift the original data stream L times to generate L data streams;

[0058] Operation 202: Extract the periodic code pattern from each data stream and calculate the number of times each periodic code pattern repeats; and

[0059] Operation 203: Determine the periodic code pattern extracted from the output signal based on the number of repetitions of the periodic code pattern extracted from two or more data streams.

[0060] In operation 201, the raw data stream can be obtained by performing level judgment and symbol extraction on the time-domain waveform of the output signal within a predetermined time period, thereby generating the raw data stream. The raw data stream can be a digital signal, and each bit of the digital signal can be 0 or 1. For example, the output signal is 10110101011000110, etc.

[0061] The process involves level judgment and symbol extraction on the time-domain waveform, including, for example, calculating the average level of the time-domain waveform, determining whether the level of each sampling point in the time-domain waveform is higher than the average value, and if it is higher than or equal to the average value, then the corresponding symbol for that sampling point in the original data stream is 1; if it is lower than the average value, then the corresponding symbol for that sampling point in the original data stream is 0. This allows the generation of the original data stream.

[0062] In operation 201, the output signal within a predetermined time period is shifted L times to generate L data streams. Here, L is a natural number greater than 1. The predetermined time period is, for example, 10 seconds or 15 seconds. L is the length of the periodic code pattern, that is, the number of bits contained in the periodically occurring code pattern. For example, for the data stream 0101010101, the periodic code pattern is 01, and the length of the periodic code pattern is 2. Therefore, in operation 201, the output signal within the predetermined time period is shifted twice to generate two data streams.

[0063] In operation 201, when performing L shifts, the shifts can be performed sequentially in the same direction. The k-th shift moves the output signal within the predetermined time period k positions to the left or right, where k is a natural number and is less than or equal to L. For example, the first shift moves the output signal within the predetermined time period one position to the left or right, the second shift moves the output signal within the predetermined time period two positions to the left or right, and so on.

[0064] like Figure 2 As shown, before operation 201, the initial value of L can be set through operation 204. After operation 202, operation 205 can be used to determine whether L is greater than 1. If it is, then operation 206 is entered, the result of L-1 is assigned to L, and then operation 201 is returned. In this way, it is possible to traverse the cases where L changes from its maximum value to 1.

[0065] Furthermore, in operation 205, when the judgment is negative (i.e., L is less than or equal to 1), it means that L becomes the minimum value. That is, for each value of L from the maximum value to the minimum value, the extraction of the same code pattern in each data stream is completed respectively.

[0066] In operation 202, for each of the L data streams generated in operation 201, the periodic code pattern in that data stream is extracted, and the number of times each periodic code pattern repeats is calculated. That is, operation 202 is performed for each of the L data streams generated in operation 201.

[0067] like Figure 2 As shown, operation 202 may include the following operations:

[0068] Operation 2021: Calculate the number of occurrences of the same code pattern with an interval of n bits and a length of L in the data stream, where n is 0 or a natural number; and

[0069] Operation 2022: When the number of occurrences of the same code pattern is greater than a predetermined value (i), the same code pattern is determined to be a periodic code pattern.

[0070] In Operation 2021, for this data stream, a code pattern of length L can be extracted at n-bit intervals. When the code patterns are identical, the number of consecutive occurrences of the same code pattern is determined. Consecutive occurrences of the same code pattern mean that identical code patterns are spaced n bits apart. For example, for the code stream 01... 001 00 001 11 001 001 is the same code pattern, and there is a 2-bit interval between the same code patterns. The number of consecutive occurrences of the same code pattern is 3.

[0071] By setting n, the extraction range of periodic codes can be expanded, which facilitates the improvement of the chip's electromagnetic interference performance. For example, if the code pattern xy01 appears repeatedly in the data stream, where x and y are arbitrary values, this code pattern will also generate high electromagnetic radiation energy. Therefore, in operation 2021, by setting n to 2, the same code pattern 01 can be extracted, thus avoiding the omission of important codes that have a significant impact on electromagnetic radiation. As another example, when n is 3, if xyz01 appears repeatedly in the data stream, where x, y, and z are arbitrary values, in operation 2021, by setting n to 3, the same code pattern 01 can be extracted.

[0072] In Operation 2021, for a data stream, one or more identical code patterns can be extracted, and the number of consecutive occurrences of each identical code pattern can be recorded.

[0073] In operation 2022, for each of the extracted identical code patterns, it is determined whether the number of consecutive occurrences of the identical code pattern is greater than a predetermined value i, where i can be a natural number. If the determination is negative, the record information for that identical code pattern is discarded. If the determination is positive, operation 2023 is performed to record the identical code pattern and the number of times it occurs.

[0074] like Figure 2 As shown, operation 202 also includes:

[0075] Operation 2024: Determine if n is equal to 0. If not, proceed to operation 2025, assign the value of n-1 to n, and return to operation 2021 to extract the same code pattern again for the updated n. If yes, end operation 202 and proceed to the next operation, for example, to operation 205.

[0076] Furthermore, in at least one embodiment, such as Figure 2 As shown, before operation 2021, the initial value of n can be set through operation 2026, and n can be less than L.

[0077] like Figure 2 As shown, in operation 203, all the same code patterns extracted in operation 202 can be sorted in descending order of the number of repetitions, and the first T code patterns can be used as the periodic code patterns extracted from the output signal within the predetermined time period.

[0078] For example, such as Figure 2 As shown, operation 203 may include:

[0079] Operation 2031: Sort all identical code patterns extracted in operation 202 in descending order of the number of times they appear;

[0080] Operation 2032: Specify the number T of code patterns to be extracted. For example, the user can input T through an input device to specify the number T of code patterns to be extracted; and

[0081] Operation 2033: Output T code patterns. For example, extract the first T code patterns according to the order of repetition frequency obtained in operation 2031 from most to least frequent, as periodic code patterns. The extracted T periodic code patterns can be output to a display device for display.

[0082] In operation 2031, when calculating the number of times the same code pattern repeats, to prevent identical code patterns from affecting the calculation result, it can be determined whether there are identical code patterns. If multiple identical code patterns appear, the code pattern with the most recurring frequency among the multiple identical code patterns is taken as a single identical code pattern, and the other code patterns among the multiple identical code patterns are discarded. For example, the recurrence frequency of the discarded code patterns can be no longer recorded. In this way, in operation 2031, after excluding identical code patterns, the remaining identical code patterns can be sorted.

[0083] In one specific implementation, the method for determining whether there are identical code patterns is as follows: For example, M (M is a natural number) identical code patterns extracted by operation 202, perform a self-loop or self-addition on each identical code pattern and then perform a self-loop to obtain a looped code pattern. Determine whether the looped code pattern is the same as at least one other identical code pattern. If they are the same, it is determined to be an identical code pattern. For example: the kth identical code pattern is 0011, which appears 100 times; the lth identical code pattern is 0110, which appears 90 times; the mth identical code pattern is 1001, which appears 98 times. After looping through the kth identical code pattern, we get three code patterns: 0110, 1100, and 1001. Among them, 0110 is the same as the lth identical code pattern, and 1001 is the same as the mth identical code pattern. Therefore, the kth identical code pattern, the lth identical code pattern, and the mth identical code pattern are identical. Thus, we keep the kth identical code pattern with the most repetitions and discard the lth and mth identical code patterns.

[0084] In addition, Figure 2 The system can also include operation 207. In operation 207, consecutive 0 or 1 bits with a length greater than w in the output signal for the predetermined time period can be removed, thereby reducing the amount of computation.

[0085] The electromagnetic interference (EMI) analysis method of this application will be illustrated below with a specific example.

[0086] Step 1: To generate output signals that closely resemble those in actual EMI testing, it is necessary to load correct and reliable excitation signals onto the chip interface in the chip's simulation module. This ensures that the actual EMI test results are accurately reflected. The excitation signals should include at least the following three types: First, using the chip's built-in self-test pattern as the excitation signal, such as MBIST for testing memory; Second, simulating periodic bit streams like 01010101… and 001100110011 under the most extreme EMI conditions as input excitation signals. For example, the DQ line of memory can be repeatedly read and written using 0x5555, 0xAAAA, 0x3333, and 0xCCCC as excitation signals over a time period (e.g., a burst) to generate the output signal; Third, the excitation signals should cover the data stream patterns of the output signals under normal random conditions, such as allowing idle data streams, allowing full-load operation, and other random states.

[0087] Step 2: Perform Fourier transform on the output signals generated by various excitation signals respectively. If the Fourier transform result shows discrete frequency peaks, compare the discrete frequency peak information with the simulation and measurement results of the previous generation interface to determine whether the chip meets the predetermined electromagnetic interference (EMI) requirements.

[0088] For example, Figure 3 This is the Fourier transform result of the output signal generated by the C / A line of the graphics card's GDDR6, with the horizontal axis representing frequency and the vertical axis representing power density. Notably, there are peak radiation points (301-307) at the fundamental frequency and half-harmonic frequency of the C / A line. These peak radiation points have been found in actual system-level EMI measurements to cause the chip to fail to meet the predetermined electromagnetic interference requirements. Therefore, Figure 3 The Fourier transform results shown indicate that the chip does not meet the predetermined electromagnetic interference requirements.

[0089] Step 3: When it is determined in Step 2 that the chip does not meet the predetermined electromagnetic interference requirements, extract the periodic code pattern from the output signal (e.g., based on this application). Figure 1 (The extraction is performed using method 104). Combined with the peak radiation points obtained in step 2, analyze which periodic codes are responsible for the generation of the peak radiation points. For example, perform a Fourier transform on the extracted periodic codes to obtain the peak radiation points corresponding to each of these periodic codes. If the peak radiation point is related to... Figure 3 If the frequency positions of the peak radiation points are the same, then this periodic code pattern is what causes... Figure 3 The code pattern of this spike radiation point. For example, analysis revealed that it caused... Figure 3 The periodic code patterns of the peak radiation points are mainly the two types: xy11 (xyz1) and x1. Among them, xy11 causes peak radiation at the 1 / 2 harmonic frequency point, and x1 causes peak radiation of the fundamental frequency of C / A and its harmonics.

[0090] Step 4: After determining the periodic code pattern, based on the interface protocol, the reason for generating xy11 and x1 is that the C / A always sends two bits together. When in the idle state, these two bits are forced to a high level, becoming '11'. Therefore, when the interface is stimulated by an input signal, a data stream corresponding to 'read-IDLE-read-IDLE-write-IDLE…' will appear, i.e., a data stream like xy11xy11xy11… where "11" corresponds to idle. The longer the periodicity in the time domain, the higher the energy of the discrete peak radiation points in the frequency domain, ultimately causing the chip to fail to meet the predetermined electromagnetic interference (EMI) requirements.

[0091] Step 5: Based on the periodic code pattern extracted in Step 3 and the reasons determined in Step 4, the chip design can be modified as follows: Modify the chip design so that the C / A line is not pulled high 11 in the idle state. For example, in the idle state, the signals on the C / A line and other signal lines have at least two symbol elements. Specifically, in one example, the C / A line and other signal lines can be forced to remain unchanged from the previous state, i.e., from xy11 to xyyy, where the latter two y's represent the same state as the first y. In another example, in the idle state, the signals on the C / A line and other signal lines can be made to change randomly (e.g., become pseudo-random signals); and / or, the CABI-AC protocol can be adjusted. Based on the adjusted protocol, the data of the current frame can be compared with the data of the previous frame to determine the number of times the current frame needs to be flipped. If the number of times exceeds a predetermined threshold (e.g., CABI_THRESH), the data of the current frame is flipped, thereby destroying the periodicity of the output signal and improving the peak radiation of the corresponding harmonic frequency point (e.g., 1 / 2 harmonic frequency point) of the C / A. In another example, modifying the chip design can be done as follows: If a signal transmitted through a certain signal line or interface is found to have periodic symbols, where a set of periodic symbols contains T symbols, the chip design can be modified so that for that signal line or interface, W sets of random symbols are inserted every R sets of these periodic symbols. Each set of random symbols can contain S symbols, where R, S, T, and W are all natural numbers. S can be equal to T, less than T, or greater than T. The larger S is, the more significant the reduction in electromagnetic radiation; the larger W is, the more significant the reduction in electromagnetic radiation; and the smaller R is, the more significant the reduction in electromagnetic radiation.

[0092] Step 6: For the modified chip design described in Step 5, use a Register Transfer Level (RTL) programming language (e.g., hardware description languages ​​such as VHDL / Verilog / System Verilog) to describe the circuit in the form of inter-register transfers, and then perform logic synthesis to form a new simulation module corresponding to the modified chip design. Then, return to Step 1, reload the excitation signal for the new simulation module, generate the output signal, and perform a Fourier transform on the output signal again in Step 2. Figure 4 This is a schematic diagram of the result of performing another Fourier transform on the output signal. For example... Figure 4 As shown, the peak frequencies 301a to 307a in the 0-10GHz frequency range decreased by more than 15 dB compared to 301 to 307.

[0093] According to the embodiment of the first aspect, during the chip design phase, an excitation signal is input to the chip's simulation module to generate an output signal. Time-frequency analysis is then performed on this output signal, and the chip's compliance with predetermined electromagnetic interference requirements is determined based on the results of the time-frequency analysis. Therefore, electromagnetic interference analysis can be performed during the chip design phase, which helps reduce electromagnetic interference problems during chip design and thus lowers the design cost of electronic products.

[0094] Second aspect of the embodiments

[0095] The second aspect of this application provides an electromagnetic interference analysis apparatus for a chip, which corresponds to the electromagnetic interference analysis method for a chip in the first aspect.

[0096] like Figure 5 As shown, the electromagnetic interference analysis device 500 includes:

[0097] The excitation signal input unit 501 inputs an excitation signal to the simulation module during chip design verification, so that the simulation module generates an output signal based on the circuit structure of the chip.

[0098] The time-frequency analysis unit 502 performs time-frequency analysis on the output signal to obtain the spectrum information of the output signal; and

[0099] The judgment unit 503 determines whether the chip meets the predetermined electromagnetic interference (EMI) requirements based on the spectrum information.

[0100] like Figure 5 As shown, the electromagnetic interference analysis device 500 also includes:

[0101] The periodic code extraction unit 504 extracts the periodic code from the output signal.

[0102] In at least one embodiment, the periodic code pattern extraction unit 504 extracts a periodic code pattern from the output signal, including:

[0103] The time-domain waveform of the output signal within a predetermined time period is subjected to level judgment and symbol extraction to obtain the original data stream;

[0104] The original data stream is shifted L times to generate L data streams, where L is a natural number greater than 1;

[0105] Extract the periodic code patterns from each data stream and calculate the number of times each periodic code pattern repeats; and

[0106] The periodic code pattern extracted from the output signal is determined based on the number of repetitions of the periodic code pattern extracted from the two or more data streams.

[0107] In at least one embodiment, the periodic code pattern extraction unit 504 extracts the periodic code pattern from each data stream, including:

[0108] Calculate the number of occurrences of the same code pattern with an interval of n bits and a length of L in the data stream; and

[0109] When the number of occurrences of the same code pattern is greater than a predetermined value, the same code pattern is determined to be a periodic code pattern, where n is 0 or a natural number.

[0110] like Figure 5 As shown, the electromagnetic interference analysis device 500 also includes:

[0111] The scheme modification unit 505 modifies the chip design scheme based on the periodic code pattern.

[0112] In the second aspect of the embodiment, a detailed description of each unit of the electromagnetic interference analysis device 500 can be found in the description of the corresponding steps in the first aspect of the embodiment.

[0113] Third aspect of the embodiments

[0114] A third aspect embodiment provides an electronic device having the electromagnetic interference analysis device 500 described in the second aspect embodiment.

[0115] The electronic device may be, for example, a computer, server, workstation, laptop computer, smartphone, etc.; however, the embodiments of this application are not limited thereto.

[0116] Figure 6 This is a schematic diagram of an electronic device. For example... Figure 1 As shown, the electronic device 600 may include a processor (e.g., a central processing unit, CPU) 610 and a memory 620; the memory 620 is coupled to the central processing unit 610. The memory 620 can store various types of data; it also stores an information processing program 621, and executes the program 621 under the control of the processor 610.

[0117] In some embodiments, the functionality of the electromagnetic interference analysis device 500 is integrated into the processor 610. The processor 610 is configured to implement the methods described in the embodiments of the first and third aspects.

[0118] In some embodiments, the electromagnetic interference analysis device 500 is configured separately from the processor 610. For example, the electromagnetic interference analysis device 500 can be configured as a chip connected to the processor 610, and the function of the electromagnetic interference analysis device 500 can be realized through the control of the processor 610.

[0119] In addition, such as Figure 6As shown, the electronic device 600 may also include: an input / output (I / O) device 630 and a display 640, etc.; the functions of the above components are similar to those in the prior art, and will not be described in detail here. It is worth noting that the electronic device 600 is not necessarily required to include... Figure 6 All components shown; in addition, the electronic device 600 may also include Figure 6 For components not shown, please refer to relevant technologies.

[0120] Embodiments of this application also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method in the embodiments of the first aspect.

[0121] Embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect.

[0122] Embodiments of this application also provide a computer program product, the computer program product including a computer program that, when executed by a processor, implements the method in the embodiments of the first aspect.

[0123] The acquisition, storage, use, and processing of data in the various embodiments of this application all comply with the relevant provisions of national laws and regulations.

[0124] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a fully hardware embodiment, a fully software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0125] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0126] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0127] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0128] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A periodic code pattern extraction unit, wherein the periodic code pattern extraction unit extracts a periodic code pattern from an original data stream, wherein the periodic code pattern refers to the same code pattern that appears cyclically after an interval of n bits, wherein... n is 0 or a natural number. The characteristic feature is that the periodic code pattern extraction unit extracts periodic codes from the original data stream, including: The original data stream is shifted L times to generate L data streams, where L is a natural number greater than 1; Extract the periodic code patterns from each data stream and calculate the number of times each periodic code pattern repeats; and The periodic code pattern extracted from the original data stream is determined based on the number of times the periodic code pattern is repeated from two or more of the data streams.

2. The periodic code pattern extraction unit as described in claim 1, characterized in that, Extract the periodic code pattern from each data stream, including: Calculate the number of occurrences of the same code pattern with a length of L that appears cyclically after an interval of n bits in the data stream; and When the number of occurrences of the same code pattern exceeds a predetermined value, the same code pattern is determined to be a periodic code pattern.

3. An electromagnetic interference analysis device for a chip, characterized in that, The device includes: The periodic code pattern extraction unit as described in claim 1 or 2; and The scheme modification unit modifies the chip design scheme based on the extracted periodic code pattern. The original data stream originates from the output signal generated by the simulation module in response to the excitation signal based on the circuit structure of the chip.

4. The electromagnetic interference analysis device as described in claim 3, characterized in that, Modifying the design of the chip, including: By modifying the circuit structure or the operating protocol of the interface to flip bits in the signal when the periodic code pattern causing electromagnetic interference is detected; and / or Scrambling the chip's output signal; and / or The reference clock of the chip is subjected to spectrum spreading processing.

5. A method for extracting periodic code patterns from a raw data stream, wherein the periodic code pattern refers to the same code pattern that appears cyclically after an interval of n bits, wherein... n is 0 or a natural number, characterized in that the method includes: The original data stream is shifted L times to generate L data streams, where L is a natural number greater than 1; Extract the periodic code patterns from each data stream and calculate the number of times each periodic code pattern repeats; and The periodic code pattern extracted from the original data stream is determined based on the number of times the periodic code pattern is repeated from two or more of the data streams.

6. The method as described in claim 5, characterized in that, Extract the periodic code pattern from each data stream, including: Calculate the number of occurrences of the same code pattern with a length of L that appears cyclically after an interval of n bits in the data stream; and When the number of occurrences of the same code pattern exceeds a predetermined value, the same code pattern is determined to be a periodic code pattern.

7. A method for analyzing electromagnetic interference in a chip, characterized in that, The method includes: Extracting periodic code patterns from the original data stream based on the method described in claim 5 or 6; and Based on the extracted periodic code pattern, the chip design is modified. The original data stream originates from the output signal generated by the simulation module in response to the excitation signal based on the circuit structure of the chip.

8. The electromagnetic interference analysis method as described in claim 7, characterized in that, Modifying the design of the chip, including: By modifying the circuit structure or the operating protocol of the interface to flip bits in the signal when the periodic code pattern causing electromagnetic interference is detected; and / or Scrambling the chip's output signal; and / or The reference clock of the chip is subjected to spectrum spreading processing.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method described in any one of claims 5 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method described in any one of claims 5 to 8.

11. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method described in any one of claims 5 to 8.

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