Amplitude-phase calibration method and device with variable sampling rate and measuring instrument

Abstract

The invention belongs to the technical field of electronic test and measurement, and particularly relates to a variable-sampling-rate amplitude-phase calibration method, a signal processing device and an electronic measuring instrument, and the method comprises the steps: obtaining a basic sequence; acquiring a currently configured input sampling rate of the measuring instrument, calculating a stepping variable according to a ratio of the input sampling rate to the maximum sampling rate, and calculating a sampling rate matching parameter according to the input sampling rate; generating a transition sequence according to the step variable and the coefficient window sequence; performing convolution operation on the transition sequence and the basic sequence to generate a convolution sequence, and copying and splicing the convolution sequence to generate a to-be-processed sequence; and determining an interpolation factor and an extraction factor according to the sampling rate matching parameter, performing interpolation processing on the to-be-processed sequence, and performing extraction processing after a central peak value is positioned to generate a target sequence adaptive to the input sampling rate. According to the method, the production cost and the storage pressure are greatly reduced, and meanwhile, the measurement accuracy is ensured.

Description

Technical Field

[0001] This application relates to the field of electronic test and measurement technology, and in particular to a variable sampling rate amplitude and phase calibration method, signal processing device, and electronic measuring instrument. Background Technology

[0002] With the rapid development of electronic technology and the continuous improvement of communication speed, higher requirements are being placed on signal measurement. However, the components used in actual circuits cannot be perfectly linear or ideal. Nonlinear and non-ideal circuits can cause corresponding deviations in the measured signal, thus affecting the accuracy of the measurement. Furthermore, in the use and application of some functions of test and measurement instruments, the sampling rates of analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) vary, making it difficult to cover all data points with a single intermediate frequency calibration coefficient. Matching calibration for each sampling rate and generating and storing the data would result in a large data volume and significant time consumption, substantially increasing hardware and production / testing costs.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art.

[0004] Application content In view of at least one of the above technical problems, this application provides a variable sampling rate amplitude and phase calibration method, a signal processing device, and an electronic measuring instrument.

[0005] Firstly, a variable sampling rate amplitude and phase calibration method is provided, applied in a measuring instrument, the measuring instrument including a variable sampling rate digital signal processor, the method comprising: Obtain the base sequence, which is the amplitude and phase calibration coefficient obtained by testing the measuring instrument at the maximum sampling rate; Obtain the input sampling rate currently configured on the measuring instrument, calculate the step variable based on the ratio of the input sampling rate to the maximum sampling rate, and calculate the sampling rate matching parameter based on the input sampling rate; A transition sequence is generated based on the step variable and the coefficient window sequence, which is pre-stored. The transition sequence and the base sequence are convolved to generate a convolution sequence, and the convolution sequence is copied and concatenated to generate the sequence to be processed. Based on the sampling rate matching parameters, the interpolation factor and extraction factor are determined, the sequence to be processed is interpolated, and after the center peak is located, extraction is performed to generate a target sequence that matches the input sampling rate. The target sequence definition is loaded into the digital signal processor, and the amplitude and phase of the intermediate frequency signal after passing through the digital signal processor are calibrated.

[0006] This method eliminates the need to store bulky calibration tables for every possible sampling rate. With only one factory calibration, it can generate high-precision calibration parameters in real time when the user uses any sampling rate, greatly reducing production costs and storage pressure while ensuring measurement accuracy.

[0007] In some possible implementations, the step variable is calculated using the following formula: , where X step S is a step variable. in S is the input sampling rate. max Maximum sampling rate; The sampling rate matching parameter is calculated using the following formula: E mult As the sampling rate matching parameter, ROUNDUP(Sin / 100kHz,0) is a function of S... in Round up to 100kHz and retain 0 decimal places.

[0008] In some possible implementations, the transition sequence is generated, including: Determine if n equals 44; If not, proceed. ; Based on the step variable, the first intermediate variable is calculated using the following formula: , where X step_x [n] is the first intermediate variable, X step For step variables; The second intermediate variable is calculated based on the first intermediate variable using the following formula: , where X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The third intermediate variable is calculated using the following formula, based on the second and first intermediate variables: Among them, X step_3x [n] is the third intermediate variable, X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The transition sequence is calculated using the following formula, based on the third intermediate variable and the coefficient window sequence: , where X step_4x [n] is the transition sequence, X step_3x [n] is the third intermediate variable, X c [n] represents the coefficient window sequence; Re-execute the check if n equals 44; if not, execute... The first intermediate variable, the second intermediate variable, the third intermediate variable, and the transition sequence are calculated sequentially; if so, convolution operations are performed to generate a convolution sequence.

[0009] In some possible implementations, the sequence to be processed is generated, including: The convolutional sequence generated by convolving the transition sequence with the base sequence is copied three times and concatenated end to end to form the sequence to be processed.

[0010] In some possible implementations, the interpolation factor and decimation factor are calculated, including: Based on the sampling rate matching parameter, the first divisor and the second divisor are calculated by determining whether the parameter can be divided by a preset set of bases. The interpolation factor is calculated using the following formula based on the first divisor, the second divisor, and the input sampling rate: Where int_factor is the interpolation factor, S in E is the input sampling rate. div1 E is the first divisor. div2 It is the second divisor; The extraction factor is calculated using the following formula based on the first and second divisors: Where ext_factor is the interpolation factor, E div1 E is the first divisor. div2 It is the second divisor.

[0011] In some possible implementations, interpolation is performed on the sequence to be processed, including filling the adjacent data points of the sequence with int_factor-1 zero values, where int_factor is the interpolation factor.

[0012] In some possible implementations, the central peak is located, including: Find the first peak among the first 85 data points in the interpolated sequence; Using the first peak as a marker, search for the second peak. The second peak satisfies the amplitude condition: 0.75×int_peak < int_peak2≤1.25×int_peak, where int_perk is the first peak and int_perk2 is the second peak. The second peak is defined as the center point of the target sequence.

[0013] In some possible implementations, the target sequence is generated, including: Based on the location of the second peak, one data point is taken every ext_factor-1 data points and stored in the latter half of the target sequence, where ext_factor is the interpolation factor. By utilizing the symmetry of the sequence, the data from the second half of the target sequence is assigned to the corresponding values ​​from the first half, thus generating the target sequence.

[0014] Secondly, a signal processing apparatus is provided, comprising: The digital signal processor is configured to operate at a variable sampling rate; The memory stores the amplitude and phase calibration coefficients measured at the maximum sampling rate; The processor is configured to execute an amplitude-phase calibration method to generate a target sequence at the current sampling rate and to calibrate the signal using that target sequence.

[0015] Thirdly, an electronic measuring instrument is provided, including a signal processing device.

[0016] The present application will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in 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.

[0018] Figure 1 A flowchart of the amplitude and phase calibration method provided in the embodiments of this application; Figure 2 This is a schematic diagram showing the frequency domains of the original sequence and the target sequence. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0020] In related technologies, the components used in actual circuits cannot be perfectly linear or ideal. Nonlinear and non-ideal circuits can cause corresponding deviations in the measured signal, thus affecting the accuracy of the measurement. Furthermore, in the use and application of some functions of test and measurement instruments, the sampling rates of analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) vary. This makes it difficult to cover all possible needs with a single intermediate frequency calibration coefficient. Matching calibrations to various sampling rates and generating and storing the data would result in a large data volume and significant time consumption, substantially increasing hardware and production / testing costs.

[0021] Figure 1 A flowchart illustrating the amplitude and phase calibration method provided in this application embodiment. Figure 1 As shown, this embodiment provides a variable sampling rate amplitude and phase calibration method, applied in a measuring instrument. The measuring instrument includes a variable sampling rate digital signal processor, and the method includes: Step S100: Obtain the basic sequence, which is the amplitude and phase calibration coefficient obtained by testing the measuring instrument at the maximum sampling rate; In step S100, the maximum sampling rate of the measuring instrument is set to 250MHz. A standard signal is input through a precision source, and the amplitude and phase error under this condition is tested and calculated, generating a set of amplitude and phase calibration coefficients with a length of n=43. The amplitude and phase calibration coefficients are then stored in memory.

[0022] Step S200: Obtain the input sampling rate currently configured on the measuring instrument, calculate the step variable based on the ratio of the input sampling rate to the maximum sampling rate, and calculate the sampling rate matching parameter based on the input sampling rate; In step S200, when the user configures the measuring instrument to an arbitrary sampling rate, i.e., the user inputs the sampling rate through the measuring instrument, the step variable and sampling rate matching parameter can be calculated based on the input sampling rate. Specifically, the step variable is calculated using the following formula: , where X step S is a step variable. in S is the input sampling rate. max This represents the maximum sampling rate.

[0023] The sampling rate matching parameter is calculated using the following formula: E mult For the sampling rate matching parameter, ROUNDUP(S) in / 100kHz,0) is a function of S in Round up to 100kHz and retain 0 decimal places.

[0024] For example, assuming an input sampling rate of 125MHz and a maximum sampling rate set to 250MHz, the step variable is 125 / 250 = 0.5. The sampling rate matching parameter is E. mult =ROUNDUP(125 / 100,0)=1250.

[0025] Step S300: Generate a transition sequence based on the step variable and the coefficient window sequence, wherein the coefficient window sequence is pre-stored; In step S300, in order to achieve high-precision frequency domain transformation, this embodiment constructs a transition sequence based on the Sinc function.

[0026] Specifically, the transition sequence is generated, including: Determine if n is equal to 44, where n is a variable and its value range corresponds to the sequence length; If not, proceed. ; Based on the step variable, the first intermediate variable is calculated using the following formula: , where X step_x [n] is the first intermediate variable, X step For step variables; The second intermediate variable is calculated based on the first intermediate variable using the following formula: , where X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The third intermediate variable is calculated using the following formula, based on the second and first intermediate variables: Among them, X step_3x [n] is the third intermediate variable, X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The transition sequence is calculated using the following formula, based on the third intermediate variable and the coefficient window sequence: , where X step_4x [n] is the transition sequence, X step_3x [n] is the third intermediate variable, X c [n] represents the coefficient window sequence; Re-execute the check if n equals 44; if not, execute... The first intermediate variable, the second intermediate variable, the third intermediate variable, and the transition sequence are calculated sequentially; if so, convolution operations are performed to generate a convolution sequence.

[0027] It is understandable that the above steps for generating the transition sequence utilize the step variable in step S200, and then generate the transition sequence through the first intermediate variable, the second intermediate variable, and the third intermediate variable.

[0028] Step S400: Perform convolution operation between the transition sequence and the base sequence to generate a convolution sequence, and copy and concatenate the convolution sequence to generate the sequence to be processed; specifically, generating the sequence to be processed includes: continuously copying the convolution sequence generated by convolving the transition sequence and the base sequence three times and concatenating the beginning and end to form the sequence to be processed.

[0029] In step S400, to fuse the base sequence and provide sufficient resampled data length, the generated transition sequence is convolved with the base sequence to obtain a convolutional sequence with a length of approximately 85 bits. Then, the convolutional sequence is copied three times and concatenated end-to-end to generate a sequence to be processed with a length of approximately 255 bits. This is done to avoid edge effects caused by subsequent interpolation filtering.

[0030] Step S500: Based on the sampling rate matching parameters, determine the interpolation factor and extraction factor, perform interpolation processing on the sequence to be processed, and perform extraction processing after locating the center peak to generate a target sequence that matches the input sampling rate. In step S500, the sampling rate is transformed through interpolation, alignment, and decimation.

[0031] First, calculating the interpolation factor and the extraction factor includes: Based on the sampling rate matching parameter, the first divisor and the second divisor are calculated by determining whether the parameter can be divided by a preset set of bases. The interpolation factor is calculated using the following formula based on the first divisor, the second divisor, and the input sampling rate: Where int_factor is the interpolation factor, S in E is the input sampling rate. div1 E is the first divisor. div2 It is the second divisor; The extraction factor is calculated using the following formula based on the first and second divisors: Where ext_factor is the interpolation factor, E div1 E is the first divisor. div2 It is the second divisor.

[0032] Based on the sampling rate matching parameter, the first and second divisors are calculated by determining whether the parameter is divisible by a preset set of bases. It can be understood that, firstly, the first divisor is determined, and then E is judged... mult Is it divisible by 2? If so, determine if it is divisible by 4 (if so, then E). div1 =4, otherwise E div1 =2); if not divisible by 2, then E div1 =1. Then, determine the second divisor and judge E. multIf divisible by 5, then check if divisible by 25, 125, and 625 in that order. Set E based on the largest divisible number. div2 For example, E mult If E is divisible by 125 but not by 625, then E div2 =125.

[0033] Secondly, the interpolation process for the sequence to be processed includes: interpolating the sequence by multiplying the interpolation factor. Specifically, int_factor-1 zero values ​​are filled between adjacent data points in the sequence to be processed, where int_factor is the interpolation factor. The interpolated sequence is then passed through a low-pass filter to increase the waveform density while preserving the original waveform shape.

[0034] Furthermore, locating the center peak ensures phase alignment, thus guaranteeing amplitude and phase calibration accuracy. Specifically, locating the center peak includes: Find the first peak among the first 85 data points in the interpolated sequence; Using the first peak as a marker, search for the second peak. The second peak satisfies the amplitude condition: 0.75×int_peak < int_peak2≤1.25×int_peak, where int_perk is the first peak and int_perk2 is the second peak. The second peak is defined as the center point of the target sequence, thus ensuring that the phase delay of the new coefficients strictly matches the system requirements.

[0035] Finally, the target sequence is generated. Specifically, generating the target sequence includes: Based on the location of the second peak, one data point is taken every ext_factor−1 data points and stored in the second half of the target sequence, where ext_factor is the interpolation factor. By utilizing the symmetry of the sequence, the data from the second half of the target sequence is assigned to the corresponding values ​​from the first half, thus generating the target sequence.

[0036] For example, if the position corresponding to int_perk2 is Pos, then the next point is Pos+ext_factor, and so on. The latter half of the target sequence Xpro (positions 23 to 43) is filled in. Using the symmetry of the FIR filter, the values ​​of Xpro

[23] …Xpro

[43] are mirrored and the magnitude is given to Xpro[1]…Xpro

[21] .

[0037] Step S600: Load the target sequence definition into the digital signal processor and perform amplitude and phase calibration on the intermediate frequency signal processed by the digital signal processor.

[0038] Figure 2 This is a schematic diagram showing the frequency domains of the original sequence and the target sequence. (Example) Figure 2 As shown in the figure, after actual measurement and verification, at an input sampling rate of 125MHz, after the signal is compensated using the coefficients generated by this method, its frequency domain response highly coincides with the theoretical ideal calibration curve, and the error within the effective bandwidth is less than 0.1dB.

[0039] The amplitude and phase calibration method in this embodiment does not require storing a large calibration table for every possible sampling rate. Only one factory calibration is needed to generate high-precision calibration parameters in real time when the user uses any sampling rate, which greatly reduces production costs and storage pressure, while ensuring measurement accuracy.

[0040] This embodiment also provides a signal processing device, including: The digital signal processor is configured to operate at a variable sampling rate; The memory stores the amplitude and phase calibration coefficients measured at the maximum sampling rate; The processor is configured to execute an amplitude-phase calibration method to generate a target sequence at the current sampling rate and to calibrate the signal using that target sequence.

[0041] The amplitude and phase calibration method has been described in detail in the above embodiments and will not be repeated here.

[0042] This embodiment also provides an electronic measuring instrument, including a signal processing device.

[0043] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0046] The terms "coupled," "connected," or "connected" in the instruction manual include both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as a connection made through an electrically conductive medium, which may have parasitic inductance or capacitance. An indirect connection may also include connections made through other active or passive devices to achieve the same or similar functional purpose, such as connections made through circuits or components such as switches or follower circuits.

[0047] In the detailed description of this specification, reference is made to the accompanying drawings, which form a part thereof, wherein like reference numerals always denote like parts, and wherein exemplary embodiments are shown by way of example that may be implemented. It should be understood that other embodiments may be utilized, and structural or logical changes may be made, without departing from the scope of this application. Therefore, the following detailed description should not be considered limiting.

[0048] The various operations in the specification may be described sequentially as multiple discrete actions or operations in a manner most conducive to understanding the claimed subject matter. However, the order of description should not be construed as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. Various additional operations may be performed in additional embodiments and / or the described operations may be omitted.

[0049] Various components and devices may be referred to or shown in the singular (e.g., “MOS transistor”, “transistor”, “switch”, etc.) in this document, but only for the convenience of discussion, and any element referred to in the singular may include multiple such elements as taught herein.

[0050] The above are merely preferred embodiments of this application and do not constitute any limitation on this application. Any person skilled in the art can make many possible variations and modifications to the technical solution of this application, or modify it into equivalent embodiments, without departing from the scope of the technical solution of this application. Therefore, all equivalent changes made based on the shape, structure, and principle of this application without departing from the content of the technical solution of this application should be covered within the protection scope of this application.

Claims

1. A variable sampling rate amplitude and phase calibration method, applied in a measuring instrument, said measuring instrument including a variable sampling rate digital signal processor, characterized in that, The method includes: Obtain a base sequence, which is an amplitude and phase calibration coefficient obtained by testing the measuring instrument at the maximum sampling rate; Obtain the input sampling rate currently configured on the measuring instrument, calculate the step variable based on the ratio of the input sampling rate to the maximum sampling rate, and calculate the sampling rate matching parameter based on the input sampling rate; A transition sequence is generated based on the step variable and the coefficient window sequence, wherein the coefficient window sequence is pre-stored. The transition sequence is convolved with the base sequence to generate a convolution sequence, and the convolution sequence is copied and concatenated to generate the sequence to be processed. Based on the sampling rate matching parameters, the interpolation factor and extraction factor are determined, the sequence to be processed is interpolated, and after the center peak is located, extraction is performed to generate a target sequence that matches the input sampling rate. The target sequence definition is loaded into the digital signal processor, and the amplitude and phase of the intermediate frequency signal processed by the digital signal processor are calibrated.

2. The amplitude and phase calibration method with variable sampling rate according to claim 1, characterized in that, The step variable is calculated using the following formula: , where X step S is a step variable. in S is the input sampling rate. max Maximum sampling rate; The sampling rate matching parameter is calculated using the following formula: E mult As the sampling rate matching parameter, ROUNDUP(Sin / 100kHz,0) is a function of S... in Round up to 100kHz and retain 0 decimal places.

3. The amplitude and phase calibration method with variable sampling rate according to claim 1, characterized in that, The generation of the transition sequence includes: Determine if n equals 44; If not, proceed. ; Based on the step variables, the first intermediate variable is calculated using the following formula: , where X step_x [n] is the first intermediate variable, X step For step variables; Based on the first intermediate variable, the second intermediate variable is calculated using the following formula: , where X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The third intermediate variable is calculated using the following formula based on the second and first intermediate variables: Among them, X step_3x [n] is the third intermediate variable, X step_2x [n] is the second intermediate variable, X step_x [n] is the first intermediate variable; The transition sequence is calculated using the following formula based on the third intermediate variable and the coefficient window sequence: , where X step_4x [n] is the transition sequence, X step_3x [n] is the third intermediate variable, X c [n] represents the coefficient window sequence; Re-execute the check if n equals 44; if not, execute... The first intermediate variable, the second intermediate variable, the third intermediate variable, and the transition sequence are calculated sequentially; if so, the convolution operation is performed to generate a convolution sequence.

4. The amplitude and phase calibration method with variable sampling rate according to claim 1, characterized in that, The generation of the sequence to be processed includes: The convolutional sequence generated by convolving the transition sequence with the base sequence is copied three times consecutively and concatenated end to end to form the sequence to be processed.

5. The amplitude and phase calibration method with variable sampling rate according to claim 1, characterized in that, The calculation of the interpolation factor and the extraction factor includes: Based on the sampling rate matching parameter, the first divisor and the second divisor are calculated by determining whether the parameter can be divided by a preset set of bases. The interpolation factor is calculated using the following formula based on the first divisor, the second divisor, and the input sampling rate: Where int_factor is the interpolation factor, S in E is the input sampling rate. div1 E is the first divisor. div2 It is the second divisor; The extraction factor is calculated using the following formula based on the first and second divisors: Where ext_factor is the interpolation factor, E div1 E is the first divisor. div2 It is the second divisor.

6. The amplitude and phase calibration method with variable sampling rate according to claim 5, characterized in that, The interpolation process for the sequence to be processed includes: The adjacent data points of the sequence to be processed are filled with int_factor-1 zero values, where int_factor is the interpolation factor.

7. The amplitude and phase calibration method with variable sampling rate according to claim 5, characterized in that, The location of the central peak includes: Find the first peak among the first 85 data points in the interpolated sequence; Using the first peak as a marker, search for the second peak. The second peak satisfies the amplitude condition: 0.75×int_peak < int_peak2≤1.25×int_peak, where int_perk is the first peak and int_perk2 is the second peak. The second peak is defined as the center point of the target sequence.

8. The amplitude and phase calibration method with variable sampling rate according to claim 7, characterized in that, The generation of the target sequence includes: Based on the position of the second peak, take one data point every ext_factor-1 data points and store it in the second half of the target sequence, where ext_factor is the interpolation factor; By utilizing the symmetry of the sequence, the data from the second half of the target sequence is assigned to the corresponding values ​​from the first half, thus generating the target sequence.

9. A signal processing apparatus, characterized in that, include: The digital signal processor is configured to operate at a variable sampling rate; The memory stores the amplitude and phase calibration coefficients measured at the maximum sampling rate; The processor is configured to perform the amplitude-phase calibration method as described in any one of claims 1 to 8 to generate a target sequence at the current sampling rate and to calibrate the signal using the target sequence.

10. An electronic measuring instrument, characterized in that: Includes the signal processing apparatus as described in claim 9.

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