Frequency converter calibration method suitable for multi-channel calibration

Abstract

The invention discloses a frequency converter calibration method suitable for multi-channel calibration, and belongs to the technical field of testing. According to the invention, the direct connection error term is calculated by referring to the receiver error term, the limitation that the power calibration port is fixed as the input port in the calibration measurement process is canceled, and the acquisition of the full N port error term and the receiver error term is not influenced; after the multi-port vector network analyzer applies the new calibration technology, a single-port error term for frequency converter calibration can be easily obtained only based on full-N-port calibration covering radio frequency and intermediate frequency, then a straight-through error term for frequency converter calibration can be obtained through calculation by using the single-port error term and a reference receiver error term, and the calibration precision of the frequency converter is improved. And finally, residual receiver error terms are calculated, and solving of all error coefficients is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of testing, and in particular relates to a frequency converter calibration method suitable for multi-channel calibration. Background Art

[0002] The frequency converter is the most common frequency conversion device, which can convert an input frequency from one frequency band to a higher or lower frequency band. This feature makes the frequency converter important in the field of radio frequency applications, and its main applications include wireless communication systems, radar reception and transmission, etc.

[0003] Existing solutions use traditional systems to test inverters, which contain a large number of RF devices. Compared with using a vector network analyzer, traditional testing methods are slow, complicated to operate, and less accurate.

[0004] The existing technology is mainly a frequency converter calibration method with a fixed power calibration port. The disadvantages of the fixed power calibration port calibration method mainly include two aspects: first, when a single channel performs frequency converter calibration, the input port needs to be fixed as the power calibration port, and other ports cannot be selected for power calibration to achieve frequency converter calibration; second, there will be redundant power calibration measurement steps when calibrating multiple channels, and each step requires a manual physical connection, which is time-consuming and labor-intensive. Summary of the invention

[0005] In view of the above technical problems existing in the prior art, the present invention proposes a frequency converter calibration method suitable for multi-channel calibration, which has a reasonable design, overcomes the shortcomings of the prior art, and has good effects.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A frequency converter calibration method suitable for multi-channel calibration comprises the following steps:

[0008] Step 1: Calculate all error terms corresponding to all N-port calibrations combining multiple channel frequencies;

[0009] Step 2: Separate all error terms corresponding to the RF frequency from the results of step 1;

[0010] Step 3: Separate all error terms corresponding to the intermediate frequency from the results of step 1;

[0011] Step 4: Calculate the twelve error terms for the inverter calibration.

[0012] Preferably, step 4 specifically includes the following steps:

[0013] Step 4.1: Calculate the single-port error term for the three input ports, i.e., the source ports:

[0014]

[0015] Where: i represents the source port, ED ii represents the directional error term at the source port, ES ii represents the source mismatch error term on the source port, ER ii represents the reflection tracking error term at the source port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, All are step 2 error terms;

[0016] Step 4.2: Calculate the single-port error term for the three output ports, i.e., the receiving ports:

[0017]

[0018] Where: j represents the receiving port, ED jj represents the directional error term at the receiving port, ES jj represents the source mismatch error term at the receiving port, ER jj represents the reflection tracking error term at the receiving port, represents the directional error term corresponding to the intermediate frequency on the receiving port, represents the source mismatch error term corresponding to the intermediate frequency on the receiving port, represents the reflection tracking error term corresponding to the intermediate frequency at the receiving port, All are the error terms of step 3;

[0019] Step 4.3: Calculate the reference receiver tracking error term at the input port, i.e., the source port:

[0020]

[0021] Where: i represents the source port, RR ii represents the reference receiver tracking error term at the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, is the error term in step 2;

[0022] Step 4.4: Calculate the load mismatch error term for the input port, i.e., the source port, and the output port, i.e., the receiving port:

[0023]

[0024] Where: i represents the source port, j represents the receiving port, EL jirepresents the load matching error term from the source port to the receiving port, It represents the load matching error term corresponding to the intermediate frequency from the source port to the receiving port, EL ij represents the load matching error term from the receiving port to the source port, It represents the load matching error term corresponding to the RF frequency from the receiving port to the source receiving port. is the error term in step 2, is the error term in step 3;

[0025] Step 4.5: Calculate the transmission tracking error term of the input port, i.e., the source port, and the output port, i.e., the receiving port:

[0026]

[0027] Where: i represents the source port, j represents the receiving port, ET ji represents the transmission tracking error term from the receiving port to the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, represents the reference receiver tracking error term corresponding to the intermediate frequency at the source port, It represents the transmission tracking error term corresponding to the intermediate frequency from the source port to the receiving port, ET ij represents the transmission tracking error term from the source port to the receiving port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, represents the directional error term corresponding to the intermediate frequency at the source port, represents the source mismatch error term corresponding to the intermediate frequency on the source port, represents the reflection tracking error term corresponding to the intermediate frequency at the source port;

[0028] Step 4.6: Calculate the crosstalk error term at the input port, i.e., the source port, and the output port, i.e., the receiving port:

[0029]

[0030] Where: i represents the source port, j represents the receiving port, EX ji represents the crosstalk error term from the source port to the receiving port, It represents the crosstalk error term corresponding to the RF frequency from the source port to the receiving port, EX ij represents the crosstalk error term from the receiving port to the source port, It represents the crosstalk error term corresponding to the intermediate frequency from the receiving port to the source receiving port, is the error term in step 2, is the error term in step 3;

[0031] Step 4.7: Calculate the remaining receiver error term:

[0032]

[0033] BT jj =ET ji ·RR ii

[0034] BT ii =ET ij ·RR jj

[0035] Where: i represents the source port, j represents the receiving port, RR jj represents the reference receiver tracking error term at the receiving port, BT jj represents the measured receiver transmission tracking error term at the receiving port, BT ii represents the measured receiver transmission tracking error term at the source port.

[0036] Beneficial technical effects brought by the present invention:

[0037] The present invention can realize high-precision calibration of the frequency converter according to the new multi-channel calibration technology without reducing the accuracy; it eliminates the restriction that the power calibration port is fixed as the input port during the frequency converter calibration measurement process, and does not affect the acquisition of the full N-port error term and the receiver error term. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the signal flow graph of the error model;

[0039] Figure 2 It is the signal flow chart of the reverse error model. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] Derivation of inverter calibration error terms

[0042] Multi-channel calibration may include

[0043] Step 1: Calculate all error terms corresponding to the full N-port calibration combining multiple channel frequencies;

[0044] Step 2: Separate all error terms corresponding to the radio frequency (RF) frequency from the results of step 1;

[0045] Step 3: Separate all error terms corresponding to the intermediate frequency (IF) frequency from the result of step 1;

[0046] Step 4: If Figure 1 and Figure 2 As shown, the twelve error terms for inverter calibration are calculated as follows:

[0047] 1. Calculate the single-port error term for the three input (source) ports:

[0048]

[0049] Where: i represents the source port, ED ii represents the directional error term at the source port, ES ii represents the source mismatch error term on the source port, ER ii represents the reflection tracking error term at the source port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, are all error terms in step 2.

[0050] 2. Calculate the single-port error terms for the three output (receive) ports:

[0051]

[0052] Where: j represents the receiving port, ED jj represents the directional error term at the receiving port, ES jj represents the source mismatch error term at the receiving port, ER jj represents the reflection tracking error term at the receiving port, represents the directional error term corresponding to the intermediate frequency on the receiving port, represents the source mismatch error term corresponding to the intermediate frequency on the receiving port, represents the reflection tracking error term corresponding to the intermediate frequency at the receiving port, They are all error terms in step 3.

[0053] 3. Calculate the input (source) port reference receiver tracking error term:

[0054]

[0055] Where: i represents the source port, RR ii represents the reference receiver tracking error term at the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, is the error term in step 2.

[0056] 4. Calculate the input (source) and output (receive) port load mismatch error terms:

[0057]

[0058] Where: i represents the source port, j represents the receiving port, EL ji represents the load matching error term from the source port to the receiving port, It represents the load matching error term corresponding to the intermediate frequency from the source port to the receiving port, EL ij represents the load matching error term from the receiving port to the source port, It represents the load matching error term corresponding to the RF frequency from the receiving port to the source receiving port. is the error term in step 2, is the error term in step three.

[0059] 5. Calculate the input (source) and output (receive) port transmission tracking error terms:

[0060]

[0061] Where: i represents the source port, j represents the receiving port, ET ji represents the transmission tracking error term from the receiving port to the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, represents the reference receiver tracking error term corresponding to the intermediate frequency at the source port, It represents the transmission tracking error term corresponding to the intermediate frequency from the source port to the receiving port, ET ij represents the transmission tracking error term from the source port to the receiving port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, represents the directional error term corresponding to the intermediate frequency at the source port, represents the source mismatch error term corresponding to the intermediate frequency on the source port, represents the reflection tracking error term corresponding to the intermediate frequency at the source port.

[0062] 6. Calculate the input (source) and output (receive) port crosstalk error terms:

[0063]

[0064] Where: i represents the source port, j represents the receiving port, EX ji represents the crosstalk error term from the source port to the receiving port, It represents the crosstalk error term corresponding to the RF frequency from the source port to the receiving port, EX ij represents the crosstalk error term from the receiving port to the source port, It represents the crosstalk error term corresponding to the intermediate frequency from the receiving port to the source receiving port, is the error term in step 2, is the error term in step three.

[0065] 7. Calculate the remaining receiver error term:

[0066]

[0067] BT jj =ET ji ·RR ii

[0068] BT ii =ET ij ·RR jj

[0069] Where: i represents the source port, j represents the receiving port, RR jj represents the reference receiver tracking error term at the receiving port, BT jj represents the measured receiver transmission tracking error term at the receiving port, BT ii represents the measured receiver transmission tracking error term at the source port.

[0070] At this point, all N-port error terms and receiver error terms have been solved.

[0071] The new frequency converter calibration technology proposed in the present invention is developed in response to the complex multi-channel calibration technology of the existing full N-port vector network analyzer. It uses a measurement and calculation method different from the existing frequency converter calibration technology, calculates the through error term by referring to the receiver error term, cancels the limitation that the power calibration port is fixed as the input port during the calibration measurement process, and does not affect the acquisition of the full N-port error term and the receiver error term.

[0072] After applying this new calibration technology to the multi-port vector network analyzer, it is only necessary to perform a full N-port calibration covering both the RF frequency and the IF frequency to easily obtain the single-port error term of the converter calibration. The single-port error term and the reference receiver error term can then be used to calculate the through error term of the converter calibration. Finally, the remaining receiver error terms are calculated to achieve the solution of all error coefficients.

[0073] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A frequency converter calibration method suitable for multi-channel calibration, characterized in that: The steps include: Step 1: Calculate all error terms corresponding to all N-port calibrations combining multiple channel frequencies; Step 2: Separate all error terms corresponding to the RF frequency from the results of step 1; Step 3: Separate all error terms corresponding to the intermediate frequency from the results of step 1; Step 4: Calculate the twelve error terms for the inverter calibration.

2. The frequency converter calibration method applicable to multi-channel calibration according to claim 1, characterized in that: Step 4 specifically includes the following steps: Step 4.1: Calculate the single-port error term for the three input ports, i.e., the source ports: Where: i represents the source port, ED ii represents the directional error term at the source port, ES ii represents the source mismatch error term on the source port, ER ii represents the reflection tracking error term at the source port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, All are step 2 error terms; Step 4.2: Calculate the single-port error term for the three output ports, i.e., the receiving ports: Where: j represents the receiving port, ED jj represents the directional error term at the receiving port, ES jj represents the source mismatch error term at the receiving port, ER jj represents the reflection tracking error term at the receiving port, represents the directional error term corresponding to the intermediate frequency on the receiving port, represents the source mismatch error term corresponding to the intermediate frequency on the receiving port, represents the reflection tracking error term corresponding to the intermediate frequency at the receiving port, All are the error terms of step 3; Step 4.3: Calculate the reference receiver tracking error term at the input port, i.e., the source port: Where: i represents the source port, RR ii represents the reference receiver tracking error term at the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, is the error term in step 2; Step 4.4: Calculate the load mismatch error term for the input port, i.e., the source port, and the output port, i.e., the receiving port: Where: i represents the source port, j represents the receiving port, EL ji represents the load matching error term from the source port to the receiving port, It represents the load matching error term corresponding to the intermediate frequency from the source port to the receiving port, EL ij represents the load matching error term from the receiving port to the source port, It represents the load matching error term corresponding to the RF frequency from the receiving port to the source receiving port. is the error term in step 2, is the error term in step 3; Step 4.5: Calculate the transmission tracking error term of the input port, i.e., the source port, and the output port, i.e., the receiving port: Where: i represents the source port, j represents the receiving port, ET ji represents the transmission tracking error term from the receiving port to the source port, represents the reference receiver tracking error term corresponding to the RF frequency at the source port, represents the reference receiver tracking error term corresponding to the intermediate frequency at the source port, It represents the transmission tracking error term corresponding to the intermediate frequency from the source port to the receiving port, ET ij represents the transmission tracking error term from the source port to the receiving port, represents the directional error term corresponding to the RF frequency at the source port, represents the source mismatch error term corresponding to the RF frequency on the source port, represents the reflection tracking error term corresponding to the RF frequency at the source port, represents the directional error term corresponding to the intermediate frequency at the source port, represents the source mismatch error term corresponding to the intermediate frequency on the source port, represents the reflection tracking error term corresponding to the intermediate frequency at the source port; Step 4.6: Calculate the crosstalk error term at the input port, i.e., the source port, and the output port, i.e., the receiving port: Where: i represents the source port, j represents the receiving port, EX ji represents the crosstalk error term from the source port to the receiving port, It represents the crosstalk error term corresponding to the RF frequency from the source port to the receiving port, EX ij represents the crosstalk error term from the receiving port to the source port, It represents the crosstalk error term corresponding to the intermediate frequency from the receiving port to the source receiving port, is the error term in step 2, is the error term in step 3; Step 4.7: Calculate the remaining receiver error term: BT jj =ET ji ·RR ii BT ii =ET ij ·RR jj Where: i represents the source port, j represents the receiving port, RR jj represents the reference receiver tracking error term at the receiving port, BT jj represents the measured receiver transmission tracking error term at the receiving port, BT ii represents the measured receiver transmission tracking error term at the source port.

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