Method for generating simulation file of imt equivalent model of two-stage frequency converter

Abstract

The application discloses an IMT equivalent model simulation file generation method of a two-stage frequency converter, and comprises the following steps: constructing an IMT O-Type equivalent test model of a two-stage frequency converter to test intermodulation products, and recording the frequencies of the RF port and the IF port of the two-stage frequency converter during the test; calculating the sum / difference frequencies of the equivalent LO port; filling the frequencies of the IF port and the sum / difference frequencies of the equivalent LO port into an input test table; performing frequency scanning on the input test table to obtain an intermodulation product table; performing normalization processing on the data in the intermodulation product table to obtain an intermodulation test table; and writing the intermodulation test table into an IMT table; and importing the IMT table into an IMT O-Type model file. The local oscillator information of the two LO ports of the two-stage frequency converter is equivalently converted into the local oscillator information of one LO port, so that the obtained data conforms to the IMT-O-Type data model format and can be recognized by ADS simulation software.

Description

Technical Field

[0001] This invention relates to the field of radio frequency circuit simulation technology, specifically to a method for generating simulation files of IMT equivalent models of two-stage frequency converters. Background Technology

[0002] Test results for frequency converters are typically stored as IMT-O-Type data model files, which can be imported into simulation software for analysis. However, the IMT-O-Type data model only supports test data for single-stage frequency converters, meaning it can only store test data from one LO port. The local oscillator frequency (LO) of a single-stage frequency converter is a known signal directly provided by an external source. For two-stage frequency converters, which have two LO ports, the local oscillator information from both ports cannot be simultaneously input into the IMT-O-Type data model file. Therefore, a method is needed to equivalently replace the two local oscillator signals of a two-stage frequency converter with a single LO signal, enabling the IMT-O-Type data model file to store the test information of the two-stage frequency converter and import it into simulation software such as ADS. Summary of the Invention

[0003] The purpose of this invention is to provide a method for generating an IMT equivalent model simulation file for a two-stage frequency converter. By converting the local oscillator information of the two LO ports of the two-stage frequency converter into the local oscillator information of one LO port, and since the frequencies of the RF port and IF port of the frequency converter can be recorded, the equivalent local oscillator information of the LO port can be calculated using the frequencies of the RF port and IF port, so that the obtained data conforms to the IMT-O-Type data model format and can be recognized by the ADS simulation software.

[0004] On the one hand, this application provides a method for generating an IMT equivalent model simulation file for a two-stage frequency converter, including the following steps:

[0005] S1. Construct an equivalent test model for a two-stage mixer IMT O-Type;

[0006] S2. Perform intermodulation product testing according to the equivalent test model, and record the frequencies of the RF port and IF port of the secondary mixer during the test;

[0007] S3. Calculate the sum / difference frequency of the equivalent LO port based on the frequencies of the RF port and IF port of the secondary mixer, and fill in the frequency of the IF port and the sum / difference frequency of the equivalent LO port into the input test table;

[0008] S4. Perform frequency scanning on the input test table to obtain the intermodulation product table, normalize the data in the intermodulation product table to obtain the intermodulation test table, and write the intermodulation test table into the IMT table.

[0009] S5. Import the IMT table into the IMT O-Type model file.

[0010] Further, step S3 calculates the sum / difference frequency of the equivalent LO port. The calculation process is as follows: add / subtract the frequency of the IF port from the frequency of the RF port.

[0011] LO = RF ± IF.

[0012] Furthermore, the process of frequency scanning of the input test table is as follows:

[0013] The frequencies of the input test table are scanned, and the scan results are written into the sum and difference frequency product table.

[0014] Adjust the center frequency of the spectrum analyzer according to the frequency of the sum and difference frequency product table, and under fixed bandwidth, read the maximum power value and fill it into the intermodulation product table.

[0015] Furthermore, the frequency of the input test table is scanned, including scanning the frequency of the equivalent LO port and the frequency of the IF port by 0x, 1x, 2x and 3x, and the scan results are filled into the corresponding positions in the sum and difference frequency product table.

[0016] Furthermore, the fixed bandwidth ranges from 5 to 10 MHz.

[0017] Furthermore, the normalization process is as follows:

[0018] The average value of the sum / difference power at the LO port in the intermodulation product table is taken to obtain the average value of the left and right sidebands;

[0019] Using the IF power of 1 scan in the intermodulation product table as the reference point power, calculate the absolute values ​​of the power of other frequency points in the intermodulation product table relative to the reference point power, and write the calculation results into the corresponding position in the intermodulation test table.

[0020] Furthermore, during the normalization process, when the frequency power is 0, the value entered into the intermodulation test table is the default value.

[0021] Furthermore, before writing the cross-computation test table into the IMT table in step S5, the data in the cross-computation test table are approximated and rounded to one decimal place before being filled into the IMT table.

[0022] The beneficial effects of this invention are as follows:

[0023] Since simulation software such as ADS typically uses IMT-O-Type data model files for inverter simulation, and these files only store the local oscillator information of one LO port, this application converts the local oscillator information of the two LO ports of a secondary inverter into the local oscillator information of one LO port. Using the testable and recordable frequencies of the inverter's RF and IF ports, the local oscillator information of the LO port after conversion to a single LO port is calculated based on these frequencies. This ensures that the obtained data conforms to the IMT-O-Type data model format and can be recognized by the ADS simulation software. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the method for generating the IMT equivalent model simulation file of the two-stage frequency converter of the present invention;

[0025] Figure 2 This is a schematic diagram of the equivalent single-stage frequency converter of the two-stage frequency converter of the present invention;

[0026] Figure 3 This is a test scenario for the IMT equivalent model provided in the embodiments of the present invention;

[0027] Figure 4 This is a schematic diagram of the calibration of the IMT equivalent test model provided in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of IMT O-Type model file storage provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0031] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0032] Furthermore, for clarity and brevity, descriptions of well-known structures, functions, and configurations may have been omitted. Those skilled in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of this disclosure.

[0033] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0034] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0035] Example 1

[0036] like Figure 1 As shown, this application provides a method for generating an IMT equivalent model simulation file for a two-stage frequency converter, including the following steps:

[0037] S1. Construct an equivalent test model for a two-stage mixer IMT O-Type;

[0038] S2. Perform intermodulation product testing according to the equivalent test model, and record the frequencies of the RF port and IF port of the secondary mixer during the test;

[0039] S3. Calculate the sum / difference frequency of the equivalent LO port based on the frequencies of the RF port and IF port of the secondary mixer, and fill in the frequency of the IF port and the sum / difference frequency of the equivalent LO port into the input test table;

[0040] S4. Perform frequency scanning on the input test table to obtain the intermodulation product table, normalize the data in the intermodulation product table to obtain the intermodulation test table, and write the intermodulation test table into the IMT table.

[0041] S5. Import the IMT table into the IMT O-Type model file.

[0042] It is understandable that, such as Figure 2 As shown, the differences between a two-stage inverter IMT-O-Type and a one-stage inverter are:

[0043] Since the IMT-O-Type data model only supports single-stage frequency conversion, the local oscillator information of the second-stage frequency conversion needs to undergo equivalent transformation to conform to the IMT-O-Type data model format and be recognized by the ADS simulation software. The single-stage frequency conversion local oscillator frequency LO is the local oscillator signal directly provided by an external source and is known; the second-stage local oscillator frequencies are LO1 and LO2, but the model can only support one LO information, therefore the equivalent LO frequency is RF±IF (± values ​​are determined based on the characteristics of the mixer itself). The remaining steps are the same as for the single-stage mixer. In one specific implementation, the process of generating simulation files from model building and testing to import is as follows:

[0044] The first step is to construct an IMT O-Type test model. The equivalent test model for a two-stage mixer IMT is as follows: Figure 3 As shown, two signal fins are used to excite the RF and LO ports of the mixer, respectively. The LO ports of the two-stage mixer include ports LO1 and LO2. A spectrum analyzer is used to read the amplitudes of the harmonics and intermodulation products at the intermediate frequency output of the mixer and compare them with the amplitudes of the target intermediate frequency products to obtain an intermodulation product table.

[0045] Before testing the intermodulation products of the constructed model, the test platform and spectrum analyzer are calibrated for frequency response amplitude using a signal source and power meter. Simultaneously, the output cables and spectrum analyzer also need to be calibrated. Specifically, the input power amplitude calibration uses a power meter to calibrate the frequency response curves of the signal source and cables on the RF and LO signal reference planes. The calibration process is as follows: Figure 4 As shown.

[0046] The second step is to test the constructed IMT O-Type test model:

[0047] 1. Set test parameters:

[0048] Inverter type (upward / downward inverter)

[0049] Operating modes (fixed local oscillator / fixed intermediate frequency)

[0050] Sig signal frequency, power, and step size

[0051] LO signal frequency, power, step size

[0052] Sig mixer product order M, LO mixer product order N, maximum intermodulation product order, IMT file name (naming convention: device name_RFx_Lox_temperature).

[0053] The storage location can be customized via a specific storage path.

[0054] 2. Signal source power calibration

[0055] Sig-terminal power calibration

[0056] LO power calibration

[0057] 3. IF channel frequency response calibration

[0058] Storage power compensation file

[0059] 4. Cross-conversion product testing

[0060] 4.1 Under a certain excitation, record the frequencies of the RF port and IF port of the two-stage mixer during the test. Add / subtract the frequency of the IF port to the frequency of the RF port to calculate the sum / difference frequency of the LO port, i.e., LO = RF ± IF.

[0061] 4.2. Enter the frequency of the IF port and the sum / difference frequency of the equivalent LO port into the input test table; scan the frequency of the input test table at 0x, 1x, 2x, and 3x magnification, and enter the scan results into the corresponding positions in the sum / difference frequency product table. For each sum / difference frequency, adjust the center frequency of the spectrum analyzer according to the frequency in the sum / difference frequency product table, and under a fixed bandwidth (5-10MHz), read the maximum power value and enter it into the intermodulation product table for storage.

[0062] 4.3 Normalize the sum and difference frequency products in the cross-modulation product table:

[0063] 4.3.1 Average the sum / difference power values ​​of the LO port in the intermodulation product table to obtain the average value of the left and right sidebands;

[0064] 4.3.2. Using the IF power of 1 scan in the intermodulation product table as the reference point power, calculate the absolute values ​​of the power of other frequency points in the intermodulation product table relative to the reference point power, and write the calculation results into the corresponding positions in the intermodulation test table. When the frequency point power is 0, the value entered into the intermodulation test table is the default value, which can be set to 99.

[0065] 4.3.3. All data from the cross-conversion test table should be approximated and rounded to one decimal place before being entered into the IMT table.

[0066] This embodiment uses the NC1713C-206AM mixer as an example. The performance characteristics of this mixer are as follows:

[0067] RF / LO band: 2GHz~6GHz

[0068] IF band: DC to 2.5GHz

[0069] Inverter loss: 8dB

[0070] RF-IF isolation: 20dB

[0071] LO-IF isolation: 25dB

[0072] Lo-RF isolation: 40dB

[0073] Local oscillator power: 0dB

[0074] Testing requirements:

[0075] IF frequency: 0.6G, 0.9G, 1.2G

[0076] IF power: -20dBm, -10dBm, -5dBm, 0dBm, 5dBm, 10dBm, 15dBm

[0077] LO: 3.9G, 0dBm

[0078] The sum and difference frequency products obtained at an ambient temperature of 25 degrees Celsius, IF = 0.9 G, -20 dBm, LO = 3.9 G, and 0 dBm input are shown in Table 1.

[0079] Table 1. Sum and Difference Frequency Products

[0080]

[0081] After recording the power according to the frequencies in the sum and difference frequency product table, the resulting intermodulation product table is shown in Table 2.

[0082] Table 2. Product Exchange List

[0083]

[0084] The average of the sum and difference frequencies of the LO ports in Table 2 is taken to obtain the average values ​​of the left and right sidebands. Then, using the power at one IF frequency of -12.2 as a reference, the absolute values ​​of the power at other frequencies relative to the reference point are calculated. Taking the left and right sideband values ​​of the power at two LO frequencies as examples (-41.7 and -47.8), the average is first calculated as (-41.7 + -47.8) / 2 = -44.75. Using -12.2 as a reference, the absolute value is |-44.75 - (-12.2)| = 32.55. The intermodulation test table obtained by this method is shown in Table 3.

[0085] Table 3 Cross-check Test Form

[0086]

[0087]

[0088] All data in Table 3 of the cross-sectional area test were rounded to one decimal place and then entered into the IMT table, as shown in Table 4:

[0089] Table 4 IMT Table

[0090]

[0091] Import the IMT table into the IMT O-Type model file according to different temperatures, such as Figure 5 As shown.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for generating simulation files of the IMT equivalent model of a two-stage frequency converter, characterized in that, Includes the following steps: S1. Construct an equivalent test model for the two-stage mixer IMT O-Type; S2. Perform intermodulation product testing according to the equivalent test model, and record the frequencies of the RF port and IF port of the secondary mixer during the test; S3. Calculate the sum / difference frequency of the equivalent LO port based on the frequencies of the RF port and IF port of the secondary mixer, and fill in the frequency of the IF port and the sum / difference frequency of the equivalent LO port into the input test table; Step S3 calculates the sum / difference frequency of the equivalent LO port. The calculation process is as follows: Add / subtract the IF port frequency from the RF port frequency: LO = RF ± IF; S4. Perform frequency scanning on the input test table to obtain the intermodulation product table, normalize the data in the intermodulation product table to obtain the intermodulation test table, and write the intermodulation test table into the IMT table. S5. Import the IMT table into the IMT O-Type model file.

2. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 1, characterized in that, The process of frequency scanning of the input test table is as follows: The frequencies of the input test table are scanned, and the scan results are written into the sum and difference frequency product table. Adjust the center frequency of the spectrum analyzer according to the frequency of the sum and difference frequency product table, and under fixed bandwidth, read the maximum power value and fill it into the intermodulation product table.

3. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 2, characterized in that, The frequency scanning of the input test table includes scanning the frequency of the equivalent LO port and the frequency of the IF port at 0x, 1x, 2x and 3x, and the scanning results are filled into the corresponding positions in the sum and difference frequency product table.

4. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 2, characterized in that, The fixed bandwidth ranges from 5 to 10 MHz.

5. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 3, characterized in that, The normalization process is as follows: The average value of the sum / difference power at the LO port in the intermodulation product table is taken to obtain the average value of the left and right sidebands; Using the IF power of 1 scan in the intermodulation product table as the reference point power, calculate the absolute values ​​of the power of other frequency points in the intermodulation product table relative to the reference point power, and write the calculation results into the corresponding position in the intermodulation test table.

6. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 5, characterized in that, During the normalization process, when the power at a frequency point is 0, the value entered into the intermodulation test table is the default value.

7. The method for generating the IMT equivalent model simulation file of a two-stage frequency converter according to claim 1, characterized in that, Before writing the cross-computation test form into the IMT table in step S5, the data in the cross-computation test form are approximated and rounded to one decimal place before being entered into the IMT table.

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