Wideband measurement system and wideband characteristic measurement method

Abstract

A broadband measurement system and a broadband characteristic measurement method. The broadband measurement system includes a signal measurer and a signal converter. The signal measuring device is used to send a measurement signal belonging to a first frequency domain from its measurement port. The first port of the signal converter is used to connect to the first measurement port of the signal measuring device, and its third port is used to connect to the second measurement port of the signal measuring device. The first passive mixer of the signal converter is coupled between the first port and the second port and configured to be bidirectional, and its second passive mixer is coupled between the third port and the fourth port and configured to be bidirectional, and is used to respectively convert the signals received from the first and third ports to a second frequency domain and output them from the second and fourth ports respectively, and respectively convert the signals received from the second and fourth ports to the first frequency domain and output them from the first and third ports respectively.

Description

Technical Field

[0001] The present invention relates to a measurement technology, and in particular, to a broadband measurement system and a broadband characteristic measurement method. Background Art

[0002] As wireless communication gradually develops to the millimeter-wave frequency band, the demand for high-frequency measurement is increasing. However, many academic or industrial research institutions still only have low-frequency or mid-frequency network analyzers and cannot support high-frequency band measurement. High-frequency / broadband network analyzers are difficult to manufacture and popularize because they require many electronic devices suitable for broadband operation (such as ultra-wideband phase-locked loops, ultra-wideband switching switches). Summary of the Invention

[0003] The present invention is directed to a broadband measurement system and a broadband characteristic measurement method that enable a low-frequency network analyzer to perform high-frequency band measurement.

[0004] According to an embodiment of the present invention, the broadband measurement system includes (but is not limited to) a signal measurement device and a signal converter. The signal measurement device has a first measurement port and a second measurement port. The signal measurement device is used to send a measurement signal from the first measurement port or the second measurement port, and the frequency of the measurement signal belongs to a first frequency domain. The signal converter includes a first port, a second port, a third port, a fourth port, a first passive mixer, and a second passive mixer. The first port is used to connect to the first measurement port of the signal measurement device, and the third port is used to connect to the second measurement port of the signal measurement device. The first passive mixer is coupled between the first port and the second port and is configured to be bidirectional. The second passive mixer is coupled between the third port and the fourth port and is configured to be bidirectional.

[0005] According to an embodiment of the present invention, the broadband characteristic measurement method includes (but is not limited to) the following steps: providing the signal converter as described above. Electrically connecting the signal measurement device to one side of the signal converter. Electrically connecting a corrector to the other side of the signal converter to obtain at least one set of corrector measurement values regarding the corrector by performing a correction program. Establishing an error model based on the at least one set of corrector measurement values. Electrically connecting the signal measurement device to a device under test through the signal converter to obtain at least one set of device under test measurement values regarding the device under test. Correcting the at least one set of device under test measurement values to at least one set of device under test characteristic values according to the error model.

[0006] Based on the above, the broadband measurement system and the broadband characteristic measurement method according to the embodiments of the present invention combine the signal converter with the signal measurement device to achieve measurement in different frequency domains. Brief Description of the Drawings

[0007] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0008] Figure 1 is a component block diagram of a broadband measurement system according to an embodiment of the present invention;

[0009] Figure 2A is a circuit diagram of a passive mixer according to an embodiment of the present invention;

[0010] Figure 2B is a circuit diagram of a passive mixer according to another embodiment of the present invention. Figure 3 is a schematic diagram of a broadband measurement system according to an embodiment of the present invention;

[0011] Figure 4 is a schematic diagram of a forward error model and a reverse error model according to an embodiment of the present invention;

[0012] Figure 5A is a schematic diagram of a signal flow analysis of a forward error model according to an embodiment of the present invention;

[0013] Figure 5B is a schematic diagram of a signal analysis of a reverse error model according to an embodiment of the present invention;

[0014] Figure 6A is a schematic diagram of a simplified forward model for single-port calibration according to an embodiment of the present invention;

[0015] Figure 6B is a schematic diagram of a simplified reverse model for single-port calibration according to an embodiment of the present invention;

[0016] Figure 7A is a schematic diagram of a forward signal analysis for two-port calibration according to an embodiment of the present invention;

[0017] Figure 7B is a schematic diagram of a reverse signal analysis for two-port calibration according to an embodiment of the present invention;

[0018] Figure 8 is a flowchart of a short-open-load-thru (SOLT) calibration process according to an embodiment of the present invention;

[0019] Figure 9 is a schematic diagram of a calibration reference plane according to an embodiment of the present invention;

[0020] Figure 10 is a schematic diagram of a calibration reference plane according to an embodiment of the present invention;

[0021] Figure 11 is Figure 9 the verification result;

[0022] Figure 12 is Figure 9 and Figure 3 the measurement result of measuring the device under test;

[0023] Figure 13 is Figure 11 the partial enlarged view of;

[0024] Figure 14 is Figure 10 the measurement result of;

[0025] Figure 15 is Figure 10 the verification result of;

[0026] Figure 16 is Figure 10 and Figure 3 the measurement result of measuring the device under test;

[0027] Figure 17 is Figure 15 the partial enlarged view of;

[0028] Figure 18 It is a flowchart of a broadband characteristic measurement method according to an embodiment of the present invention.

[0029] Explanation of reference numerals in the drawings

[0030] 1: Broadband measurement system;

[0031] 10: Signal measurement device;

[0032] 30: Signal converter;

[0033] 50: Device under test;

[0034] P11, P13: Measurement ports;

[0035] P31, P32, P33, P34: Ports;

[0036] P52, P54: Ports under test;

[0037] CG: Signal generator;

[0038] MIX1, MIX2: Passive mixers;

[0039] D1~D4, T1~T4: Switches;

[0040] LO, IF, RF: Endpoints;

[0041] CP1~CP6: Calibration reference plane;

[0042] MP1, MP2: Measurement plane;

[0043] FW: Forward error model;

[0044] RV: Reverse error model;

[0045] RF IN: Input;

[0046] S 11M 、S 21M 、S 12M 、S 22M 、S 11A 、S 21A 、S 12A 、S 22A 、S 11AT 、S 21AT 、S 12AT 、S 22AT : Parameter;

[0047] E DF 、E SF 、E RF 、E XF 、E TF 、E LF 、E DR 、E SR 、E RR 、E XR 、E TR 、E LR : Error term;

[0048] S810~S870, S1810~S1860: Steps. Detailed implementation

[0049] Now, a detailed reference will be made to the exemplary embodiments of the present invention. Examples of the exemplary embodiments are illustrated in the accompanying drawings. Whenever possible, the same component symbols are used in the drawings and the description to represent the same or similar parts.

[0050] Figure 1 is a block diagram of the components of a broadband measurement system 1 according to an embodiment of the present invention. Please refer to Figure 1 , the broadband measurement system 1 includes (but is not limited to) a signal measurement device 10 and a signal converter 30. In one embodiment, during measurement, the broadband measurement system 1 is electrically connected to a device under test (DUT) 50.

[0051] The signal measurement device 10 can be a Vector Network Analyzer (VNA) or other instruments for verifying impedance parameters (Z parameters), admittance parameters (Y parameters), hybrid parameters (h parameters / g parameters), transmission parameters (ABCD parameters), scattering parameters (S parameters), or scattering transmission parameters (T parameters). In one embodiment, the signal measurement device 10 includes measurement ports P11 and P13, and is used to send measurement signals from the measurement port P11 or the measurement port P13. That is, the signal measurement device 10 provides single-port or dual-port measurement. In one embodiment, the measurement signal belongs to the first frequency domain. For example, the first frequency domain is 0 - 8 GHz or 2 - 6 GHz, but is not limited thereto.

[0052] The signal converter 30 can be an up / down converter or other converters for adjusting the signal frequency / frequency domain. The signal converter 30 includes a signal generator CG and passive mixers MIX1 and MIX2.

[0053] The signal generator CG is coupled to the passive mixers MIX1 and MIX2, and is used to generate a reference signal. In one embodiment, the signal generator CG provides a reference signal (or frequency signal, Local Oscillator (LO) signal) to the passive mixer MIX1 or MIX2. In one embodiment, the frequency of the reference signal is related to the frequency difference between the input and output of the passive mixers MIX1 and MIX2. In some embodiments, the frequency of the reference signal can be changed according to requirements or be a fixed value.

[0054] In one embodiment, the signal converter 30 includes ports P31, P32, P33, and P34. The passive mixer MIX1 is coupled between the ports P31 and P32. The passive mixer MIX2 is coupled between the ports P33 and P34. In addition, the ports P31 and P33 are respectively used to connect the measurement ports P11 and P13 of the signal measurement device 10. The ports P32 and P34 are respectively used to connect the ports under test P52 and P54 of the device under test 50.

[0055] The passive mixers MIX1 and MIX2 can be implemented by circuits. For example, Figure 2A is the circuit diagram of a passive mixer according to an embodiment of the present invention. Please refer to Figure 2A , the passive mixer includes switches D1, D2, D3, and D4. The switches D1, D2, D3, and D4 are exemplified by diodes in the figure. The endpoint LO is used to connect to the signal generator CG. The endpoint RF is used to connect to the device under test 50. In addition, the endpoint IF is used to connect to the signal measurement device 10.

[0056] Figure 2B is the circuit diagram of a passive mixer according to another embodiment of the present invention. Please refer toFigure 2B , different from Figure 2A , the passive mixer includes switches T1, T2, T3, and T4. The switches T1, T2, T3, and T4 are exemplified by transistors in the figure. In addition, the control terminal (e.g., the gate) of switch T1 is connected to the control terminal of switch T3, and the control terminal of switch T2 is connected to the control terminal of switch T4.

[0057] Figure 2A and Figure 2B The switched mixer circuit shown is taken as an example. However, in other embodiments, the passive mixers MIX1 and MIX may also be other switched passive mixers or other types of mixers.

[0058] The passive mixers MIX1 and MIX2 are both configured to be bidirectional. For example, the passive mixer MIX1 mixes the signal from port P31 and outputs the mixed signal via port P32, and the passive mixer MIX2 mixes the signal from port P33 and outputs the mixed signal via port P34. Also for example, the passive mixer MIX1 mixes the signal from port P32 and outputs the mixed signal via port P31, and the passive mixer MIX2 mixes the signal from port P34 and outputs the mixed signal via port P33.

[0059] In one embodiment, the passive mixer MIX1 converts the signal from port P31 to the second frequency domain and outputs it from port P32. If port P31 is connected to the measurement port P11 of the signal measurement device 10 and the measurement signal output by the signal measurement device 10 belongs to the first frequency domain, then the passive mixer MIX1 is to convert the signal from the first frequency domain to the second frequency domain. The second frequency domain can be 20 - 30 GHz or 10 - 30 GHz, but is not limited thereto.

[0060] In one embodiment, the passive mixer MIX1 converts the signal from port P32 to the first frequency domain and outputs it from port P31. If port P32 is connected to the DUT port P52 of the device under test 50 and the signal output by the device under test 50 belongs to the second frequency domain, then the passive mixer MIX1 is to convert the signal from the second frequency domain to the first frequency domain.

[0061] In one embodiment, the passive mixer MIX2 converts the signal from port P33 to the second frequency domain and outputs it from port P34. If port P33 is connected to the measurement port P13 of the signal measurement device 10 and the measurement signal output by the signal measurement device 10 belongs to the first frequency domain, then the passive mixer MIX2 is to convert the signal from the first frequency domain to the second frequency domain.

[0062] In one embodiment, the passive mixer MIX2 converts the signal from port P34 to the first frequency domain and outputs it from port P33. If port P34 is connected to the DUT port P54 of the device under test 50 and the signal output by the device under test 50 belongs to the second frequency domain, then the passive mixer MIX2 is to convert the signal from the second frequency domain to the first frequency domain.

[0063] For example, ports P31 and P33 are intermediate frequency (IF) ports, and ports P32 and P34 are radio frequency (RF) ports. That is, the signals from ports P31 and P33 are intermediate frequency signals (belonging to the first frequency domain), and the passive mixers MIX1 and MIX2 up-convert the intermediate frequency signals and output radio frequency signals (belonging to the second frequency domain) via ports P32 and P34 (that is, convert the intermediate frequency signals into high-frequency signals). Alternatively, the signals from ports P32 and P34 are radio frequency signals, and the passive mixers MIX1 and MIX2 down-convert the radio frequency signals and output intermediate frequency signals via ports P31 and P33 (that is, convert the high-frequency signals into intermediate frequency signals).

[0064] It should be noted that according to different design requirements, the ranges of the first frequency domain and the second frequency domain can still be changed, and the embodiments of the present invention do not impose any limitations.

[0065] The device under test 50 can be any type of radio frequency signal generating device, microwave signal generating device or antenna device. In one embodiment, the device under test 50 includes DUT ports P52 and P54.

[0066] Figure 3 is a schematic diagram of a broadband measurement system 1 according to an embodiment of the present invention. Please refer to Figure 3 , the ports P31 and P33 of the signal converter 30 are respectively connected to the measurement ports P11 and P13 of the signal measurement device 10, and the ports P32 and P34 of the signal converter 30 are respectively connected to the DUT ports P52 and P54 of the device under test 50.

[0067] It should be noted that before measuring the device under test 50, a calibration procedure must be performed first. For example, in the broadband measurement system 1, the measurement ports P11 and P13 of the signal measurement device 10 are respectively connected to the ports under test P52 and P54 of the device under test 50. The measurement planes are respectively located at the measurement ports P11 and P13. Generally speaking, the factor causing unexpected effects is that the systematic error is caused by defects in the signal measurement device 10 and the test setup (such as cables, connectors, or fixtures). The calibration procedure is to translate the measurement plane from the port end of the signal measurement device 10 to the port end of the device under test 50. That is, the calibration reference planes are respectively located at the ports under test P52 and P54. Thereby, the unexpected effects caused by the system can be excluded, and the characteristics of the device under test 50 (such as the characteristic values of the device under test) can be accurately measured.

[0068] Figure 4 It is a schematic diagram of the forward error model FW and the reverse error model RV according to an embodiment of the present invention. Please refer to Figure 4 , if the port end of the signal measurement device 10 to the port end of the device under test 50 is regarded as a two-port network, a two-port error model FW, RV of forward propagation and reverse propagation can be formed. By calibrating, the measurement planes MP1, MP2 are translated from the port end of the signal measurement device 10 to the port end of the device under test 50, and thus the true characteristics of the device under test 50 (hereinafter referred to as the characteristic values of the device under test) can be measured. That is, the calibration reference planes CP1, CP2 are located at the port end of the device under test 50. The errors caused by signal leakage in the system 1 can be classified into directivity error and crosstalk error. And various errors are further divided into forward propagation and reverse propagation, so 4 error terms can be obtained (i.e., error term E DF , E DR , E XF , E XR ). Among them, the subscript prefix D of the error term represents directivity error, and X represents crosstalk error. The subscript suffix F of the error term represents forward propagation, and R represents reverse propagation.

[0069] The errors caused by signal mismatch in the system 1 can be classified into source match error and load match error. And various errors are also divided into forward propagation and reverse propagation, so 4 error terms can be obtained (i.e., error term E SF , E SR , E LF , E LR) Among them, the subscript prefix S of the error term represents the source matching error, and L represents the load matching error.

[0070] In addition, the errors caused by the receiver frequency response in the signal measurement device 10 can be classified into Reflection Tracking Error and Transmission Tracking Error. And various errors are also divided into forward propagation and backward propagation, so four error terms can be obtained (i.e., error terms E RF 、E RR 、E TF 、E TR ). Among them, the subscript prefix R of the error term represents the reflection tracking error, and T represents the transmission tracking error.

[0071] The twelve error terms caused by the above leakage, mismatch, and frequency response can be used to analyze the two-port error model.

[0072] Specifically, Figure 5A is a schematic diagram of the signal flow analysis of the forward error model FW according to an embodiment of the present invention. Please refer to Figure 5A , Mason's rule / Mason's Gain Formula is a rule used to describe the relationship between nodes and can be used to analyze the signal flow of the two-port error model. According to the forward error model FW of forward propagation, the reflection coefficient S 11M and the transmission coefficient S 21M (i.e., the corrector measurement value) obtained by measuring the device under test 50 without correction can be obtained by the following formula:

[0073]

[0074] Figure 5B is a schematic diagram of the signal analysis of the reverse error model RV according to an embodiment of the present invention. Please refer to Figure 5B , according to the reverse error model RV of backward propagation, the reflection coefficient S 22M and the transmission coefficient S 12M (i.e., the corrector measurement value) obtained by measuring the device under test 50 without correction can be obtained by the following formula:

[0075]

[0076] Based on these four formulas (1) - (4), SOLT calibration is performed to obtain each error term. If these error terms are then substituted back into these four formulas (1) - (4), the true S-parameters (i.e., the characteristic values of the device under test) of the device under test 50 can be obtained, which are the (calibrated) parameters S 11A , S 22A , S 21A , S 12A .

[0077] Next, for the SOLT calibration procedure, single-port calibration (including short, open, and load) is first performed. At this time, the measurement port is not connected, so it is assumed in this embodiment that the parameters S 21A , S 12A are zero. Figure 6A is a schematic diagram of a simplified forward model for single-port calibration according to an embodiment of the present invention, and Figure 6B is a schematic diagram of a simplified reverse model for single-port calibration according to an embodiment of the present invention. Please refer to Figure 6A and Figure 6B , the simplified model can obtain the following formulas:

[0078]

[0079] The unconnected measurement port can be electrically connected to a calibration kit (e.g., short, open, and load calibrators) to obtain one or more sets of calibrator measurement values regarding the calibration kit by executing a calibration procedure (the calibration order of which can be changed according to requirements).

[0080] For load calibration, if the connection to the load calibrator is perfectly matched, the reflection coefficient approaches 0 (e.g., ). Substituting the condition of the reflection coefficient being zero into formulas (5) and (6), the error term E DF is equal to the reflection coefficient S 11ML measured when the load calibrator is connected but not calibrated (i.e., E DF = S 11ML ), and the error term E DR is equal to the reflection coefficient S 22ML measured when the load calibrator is connected but not calibrated (i.e., E RF = S 22ML ) (i.e., the calibrator measurement value).

[0081] In addition, connecting the load calibrator can also obtain the error terms E XF , E XR related to isolation. Among them, the error term E XF is equal to the transmission coefficient S 21ML measured when the load calibrator is connected but not calibrated (i.e., E XF= S 21ML ) and the error term E XR is equal to the penetration coefficient S measured when the load corrector is connected but not corrected 12ML (i.e., E XF = S 12ML )(i.e., the corrector measurement value). Since the penetration coefficient S cannot be actually measured 21ML and S 12ML , they may not be included in the formula subsequently

[0082] In one embodiment, during the process of establishing the error model, a part of the values in one or more sets of measurement values can be set according to the parameters of the corrector to establish the error model. In other words, one or more of the corrector measurement values (e.g., reflection coefficient or penetration coefficient) of a specific type of corrector (as measurement boundary conditions) can be brought into the error term to estimate the error model

[0083] In another embodiment, during the process of establishing the error model, a part of the values in one or more sets of corrector measurement values can be set according to the theoretical model to establish the error model. This theoretical model is the reflection coefficient and / or penetration coefficient of a specific corrector under ideal conditions. In other words, one or more of the ideal measurement values (e.g., reflection coefficient or penetration coefficient) of a specific type of corrector (as measurement boundary conditions) can be brought into the error term to estimate the error model

[0084] For example, for open - circuit and short - circuit corrections, forward propagation can be considered first. Solving the simultaneous equations of formulas (5) and (6) can obtain the error terms E RF and E SF (assuming that the ideal boundary conditions of the ideal model are: open - circuit: short - circuit: ):

[0085]

[0086] The reflection coefficient of an ideal open - circuit is 1, and the reflection coefficient of an ideal short - circuit is - 1. However, the actual reflection coefficient is usually not so ideal. If the ideal values are substituted into formulas (7) and (8) for calculation, the calculated results will have errors compared with the actual ones. To make the calculated results closer to the actual measurement results, the actually measured reflection coefficients of the open - circuit and short - circuit correctors after calibration (i.e., the corrector measurement values) obtained from the signal measurement device 10 can be directly substituted into the parameters S 11AO and S 11AS in formulas (7) and (8) to obtain the values of the error terms E RF and E SF

[0087] Then, considering the reverse propagation. Solving the simultaneous equations of formulas (5) and (6) can obtain the error term E​RR , E SR (assuming the ideal boundary conditions are, open circuit: short circuit: ):

[0088]

[0089] Similarly, in order to make the calculation results closer to the actual measurement results, the reflection coefficients (i.e., the corrector measurement values) of the open circuit and short circuit correctors actually measured after calibration obtained from the signal measurement device 10 can be directly substituted (as the measurement boundary conditions) into the parameters S of formulas (9) and (10) 22AO , S 22AS to obtain the error terms E RR , E SR values.

[0090] Next, for the through calibration of the two-port. Figure 7A is a schematic diagram for the forward signal analysis of two-port calibration according to an embodiment of the present invention, and Figure 7B is a schematic diagram for the reverse signal analysis of two-port calibration according to an embodiment of the present invention. Please refer to Figure 7A and Figure 7B , which assumes that the through corrector is the two-port error model of the device under test (or the device under test 50). From formulas (1) and (3) (assuming the ideal boundary conditions are, through: ) the error terms E LF , E LR can be obtained:

[0091]

[0092] The reflection coefficient of the ideal through is 0, and the reflection coefficient is 1. However, it is usually difficult for a real corrector to achieve ideal through. In order to make the calculation results closer to the actual measurement results, the reflection coefficients and transmission coefficients (i.e., the corrector measurement values) of the through corrector actually measured after calibration obtained from the signal measurement device 10 can be directly substituted (as the measurement boundary conditions) into the parameters S 11AT , S 22AT , S 21AT , S 12AT to obtain the error terms E LF , E LR values.

[0093] In addition, from formulas (2) and (4) (assuming the ideal boundary conditions are, through: ) the error terms E TF , E TR can be obtained:

[0094]

[0095] Similarly, in order to make the calculation results closer to the actual measurement results, the corrected reflection coefficient and transmission coefficient of the thru-calibrator actually measured by the signal measurement device 10 (i.e., the calibrator measurement value) (as the measurement boundary condition) can be directly substituted into the parameters S of formulas (13) and (114). 11AT 、S 22AT 、S 21AT 、S 12AT to obtain the error terms E TF 、E TR . In this way, twelve error terms can be obtained.

[0096] Next, connect the signal measurer 10 to the device under test 50 to obtain one or more sets of measurement values of the device under test, and solve the simultaneous equations of formulas (1) to (4), then the true S-parameters of the device under test 50 (i.e., the characteristic values of the device under test) can be obtained:

[0097]

[0098] , where and If the foregoing error terms are respectively substituted into formulas (15) to (18), then the characteristic values of the device under test can be obtained to serve as the true characteristics of the device under test.

[0099] Figure 8 is a flowchart of a short-open-load-thru (SOLT) calibration process according to an embodiment of the present invention. Please refer to Figure 8 , switch the short, load, open, and thru calibrators (step S810) (i.e., the measurement ports are respectively connected to different calibrators), and respectively obtain one or more sets of calibrator measurement values of each calibrator (for example, the parameters S 11MS 、S 22MS 、S 11ML 、S 22ML 、S 11MO 、S 22MO 、S 11MT 、S 22MT 、S 21MT 、S 12MT ) (step S820). Set the ideal boundary condition according to the calibrator measurement value and / or the theoretical model (step S830), and then the error terms can be determined (step S840). These error terms can be used to establish an error model. On the other hand, connect the device under test 50 (step S850), and the signal measurement device 10 can obtain one or more sets of measurement values of the device under test (for example, the parameters S 11MD 、S 22MD 、S 21MD, S 12MD (Step S860). The signal measurement device 10 can correct the measured value of the device under test according to an error model based on error terms to obtain one or more sets of characteristic values of the device under test (for example, S-parameters S 11AD , S 22AD , S 21AD , S 12AD )(that is, correct the measured value of the device under test to the characteristic value of the device under test) (Step S870).

[0100] In one embodiment, the broadband measurement systems 1, 2 may further include a controller (not shown in the figure). The controller may be coupled to the signal measurement device 10 and / or the signal converter 30. In one embodiment, the controller may be configured to control the range of the second frequency domain and read measurement data (such as the corrector measurement value and / or the measured value of the device under test) from the signal measurement device 10.

[0101] In one embodiment, the controller may also be configured to obtain the one or more error models according to the corrector measurement values. The establishment of the error model can refer to the derivation of the foregoing formulas (1) to (14), which will not be elaborated herein.

[0102] In one embodiment, the controller can control the signal measurement device 10 to obtain the corrector measurement value of the corrector and / or the measured value of the device under test obtained from the device under test 50 by issuing an instruction or directly outputting data by the signal measurement device 10.

[0103] In one embodiment, the controller can correct the measured value of the device under test to the characteristic value of the device under test according to an error model based on error terms. For example, the true S-parameters are obtained according to formulas (15) to (18).

[0104] In one embodiment, the controller can switch the corrector connected to the signal measurement device 10 and / or the signal converter 30 according to the correction procedure. For example, the controller provides switches respectively connected to each corrector, and turns on the corresponding corrector connected to the signal measurement device 10 and / or the signal converter 30 according to the correction item and interrupts the connection between other correctors and the signal measurement device 10 and / or the signal converter 30, but not limited thereto.

[0105] It should be noted that the foregoing correction procedure takes SOLT as an example. In other embodiments, the correction procedure can also be SOLR (Short Open Load Reciprocal), LRM (Line Reflect Match), LRM (Line ReflectMatch), LRRM (Line Reflect Reflect Match), TRL (Thru Reflect Line) or other correction procedures.

[0106] In one embodiment, system 1 further includes a storage medium coupled to the controller. The storage medium can be a hard disk, memory, USB flash drive, database, or server. In one embodiment, the storage medium is used to store the error model and / or one or more sets of measured values of the device under test, and is readable or writable by the controller or other devices. For example, the controller stores the error model in the storage medium, or the controller reads the measured values of the device under test from the storage medium.

[0107] Based on the analysis of the foregoing error model, it can be applied to the calibration of other reference planes.

[0108] Figure 9 It is a schematic diagram of calibrating reference planes CP3 and CP4 according to an embodiment of the present invention. Please refer to Figure 9 , the calibration reference plane CP3 is located at the port P31 of the signal converter 30, and the calibration reference plane CP4 is located at the port P33 of the signal converter 30. The signal measurement device 10 can perform a calibration procedure according to the calibration reference planes CP3 and CP4 to obtain an error model.

[0109] In the calibration procedure of this embodiment, the signal measurement device 10 is electrically connected to one side of the signal converter (for example, ports P31, P33) through the measurement ports P11, P13 respectively, and one or more calibrators are electrically connected to one side of the signal converter 30 (for example, ports P32, P34) to obtain one or more sets of calibrator measurement values regarding the calibrators by performing the calibration procedure. Then, the signal measurement device 30 is electrically connected to the device under test 50 through the signal converter 10 (as Figure 9 shown) to obtain one or more sets of measured values of the device under test 50. Finally, the measured values of the device under test are corrected to one or more sets of characteristic values of the device under test according to the error model.

[0110] Figure 10 It is a schematic diagram of calibrating reference planes CP5 and CP6 according to an embodiment of the present invention. Please refer to Figure 10 , the calibration reference plane CP5 is located at the measurement port P52 of the port P32 of the device under test 50, and the calibration reference plane CP6 is located at the other port P54 of the port P34 of the device under test 50. The signal measurement device 10 can perform a calibration procedure according to the calibration reference planes CP3 and CP4 to obtain an error model.

[0111] In the calibration program of the present embodiment, the signal measurement device 10 is electrically connected to one side of the signal converter (e.g., ports P31, P33) through the measurement ports P11, P13 respectively, and one or more calibrators are electrically connected to one side of the signal converter 30 (e.g., one end of the connection line for connecting the ports under test P52, P54) to obtain one or more sets of calibrator measurement values regarding the calibrators by executing the calibration program. Then, the signal measurement device 10 is electrically connected to the device under test 50 (as shown in Figure 10 ) through the signal converter 30 to obtain one or more sets of measurement values of the device under test 50. Finally, the measurement values of the device under test are corrected to one or more sets of characteristic values of the device under test according to the error model.

[0112] The following will set the measurement boundary conditions for the architectures of Figure 9 and Figure 10 , substitute them into the formula, and compare the data results accordingly.

[0113] Figure 11 is Figure 9 the verification result, Figure 12 is Figure 9 and Figure 3 the measurement result of measuring the device under test 50, Figure 13 is Figure 11 the partial enlarged view. Please refer to Figures 11 to 13 , where the thick line in the figure (i.e., the original calibration) is the curve obtained by measuring with a general ultra-wideband vector network analyzer (VNA) and then shifting its spectrum, and the thin line (i.e., the proposed calibration) is the curve obtained by the system and method proposed in the present disclosure embodiment. It can be seen from the figure that the calibration proposed in the embodiment of the present invention almost overlaps with the result obtained by using the ultra-wideband vector network analyzer.

[0114] Figure 14 is Figure 10 the measurement result, Figure 15 is Figure 10 the verification result, Figure 16 is Figure 10 and Figure 3 the measurement result of measuring the device under test 50, and Figure 17 is Figure 15 the partial enlarged view. Please refer to Figures 14 to 17 , where the thick line in the figure (i.e., the original calibration) is the curve obtained by measuring with a general ultra-wideband vector network analyzer (VNA) and then shifting its spectrum, and the thin line (i.e., the proposed calibration) is the curve obtained by the system and method proposed in the present disclosure embodiment. It can be seen from the figure that the calibration proposed in the embodiment of the present invention almost overlaps with the result obtained by using the ultra-wideband vector network analyzer.

[0115] Figure 18is a flowchart of a broadband characteristic measurement method according to an embodiment of the present invention. Please refer to Figure 18 to provide a signal converter 30 as shown in Figure 1 and Figure 3 (step S1810). Electrically connect the signal measurement device 10 to one side of the signal converter 30 (for example, Figure 1 ports P11, P13 of Figure 1 )(step 1820). Electrically connect a corrector to the other side of the signal converter 30 (for example,

[0116] ports P32, P34 of

[0117] ) to obtain one or more sets of corrector measurement values regarding the corrector by performing a calibration procedure (step S1830). Establish an error model based on the corrector measurement values (step S1840). Electrically connect the signal measurement device 10 to the device under test 50 through the signal converter 30 to obtain one or more sets of measurement values of the device under test 50 (step S1850). Correct the measurement values of the device under test to one or more sets of characteristic values of the device under test according to the error model (step S1860).

[0118] In one embodiment, a calibration reference plane CP3 is set at port P31, a calibration reference plane CP4 is set at port P33, and the calibration procedure is performed according to the calibration reference planes CP3, CP4. 21A S 12A is set to zero as described above, and open circuit is set: Short circuit:

[0119] In another embodiment, in step S1840, some values of the corrector measurement values are set according to the parameters of the corrector to establish an error model. In other words, due to signal leakage or coupling effects in the corrector, or parasitic effects of components, the corrector cannot achieve a substantial open circuit or short circuit. Therefore, some correctors will provide their actual SOLT measurement values or a look-up table (LUT) of the corresponding frequencies of their non-ideal effects. In this embodiment, this look-up table is used to replace the ideal assumptions in the previous embodiment for calibration.

[0120] For a detailed description of the foregoing steps, reference can be made toFigures 1 to 10 The description thereof will not be repeated here.

[0121] In one embodiment, when the frequency reference given by the signal converter 30 is different, the characteristics of the device under test 50 obtained after calibration may shift. Therefore, the frequency conversion value of the signal converter 30 can be controlled through the input interface provided by the controller or the signal converter 30. For example, the frequency conversion value from the first frequency domain to the second frequency domain, or the frequency conversion value from the first frequency domain to the second frequency domain. This frequency conversion value is related to the frequency of the reference signal output by the signal generator CG. Then, the signal measurement device 10 can be controlled to sweep frequencies to obtain multiple sets of corrector measurement values regarding the corrector and the frequency conversion value. For example, different frequencies are sequentially set for the reference signal (which can be several main stable frequencies or may be changed according to other requirements), and the corrector measurement values corresponding to one or more correctors are respectively obtained. The foregoing steps may be executed multiple times, but are not limited thereto.

[0122] In summary, in the broadband measurement system and the broadband characteristic measurement method according to the embodiments of the present invention, a signal converter for up-conversion or down-conversion is introduced into the system. The signal converter provides dual ports to connect the signal measurement device and provides another dual port to connect the device under test. The passive mixer is configured to be bidirectional. Thereby, a low-frequency network analyzer can be enabled to perform high-frequency measurement. And, according to the above embodiments, those of ordinary skill in the art should understand that the signal converter (dual-channel bidirectional passive up / down converter) disclosed by the present invention can be extended to a multi-channel bidirectional passive up / down converter.

[0123] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband measurement system, characterized in that, Comprising: A signal measurement device having a first measurement port and a second measurement port, the signal measurement device being configured to send a measurement signal from the first measurement port or the second measurement port, the frequency of the measurement signal belonging to a first frequency domain; A signal converter, comprising: A first port configured to connect to the first measurement port of the signal measurement device; A second port; A first passive mixer coupled between the first port and the second port and configured to be bi-directional; A third port configured to connect to the second measurement port of the signal measurement device; A fourth port; and A second passive mixer coupled between the third port and the fourth port and configured to be bi-directional, wherein the first passive mixer and the second passive mixer are configured to: Convert the signals received from the first port and the signals received from the third port to a second frequency domain and output them from the second port and the fourth port respectively; and Convert the signals received from the second port and the signals received from the fourth port to the first frequency domain and output them from the first port and the third port respectively; A controller coupled to the signal measurement device and the signal converter, the controller being configured to control the range of the second frequency domain and read measurement data from the signal measurement device; and A storage medium coupled to the controller; In a calibration procedure, the second port and the fourth port are electrically connected to a calibrator, the controller obtains a set of calibrator measurement values regarding the calibrator through the signal measurement device, and the controller further obtains an error model based on the set of calibrator measurement values and stores the error model in the storage medium.

2. The broadband measurement system according to claim 1, wherein The signal converter further includes a signal generator coupled to the first passive mixer and the second passive mixer respectively.

3. The broadband measurement system according to claim 1, wherein In a measurement procedure, the second port and / or the fourth port are electrically connected to a device under test, and the controller controls the signal measurement device to obtain at least one set of measurement values of the device under test, and based on the error model stored in the storage medium and the at least one set of measurement values of the device under test, obtains at least one set of characteristic values of the device under test.

4. A broadband characteristic measurement method, characterized in that, Comprising: Providing the signal converter according to claim 1; Electrically connecting a signal measurement device to one side of the signal converter; Electrically connecting a calibrator to the other side of the signal converter to obtain at least one set of calibrator measurement values regarding the calibrator by performing a calibration procedure; Establishing an error model based on the at least one set of calibrator measurement values; Electrically connecting the signal measurement device to a device under test through the signal converter to obtain at least one set of measurement values of the device under test; And Calibrating the at least one set of measurement values of the device under test to at least one set of characteristic values of the device under test according to the error model.

5. The broadband characteristic measurement method according to claim 4, wherein The calibration procedure is SOLT, SOLR, LRM, LRM, LRRM or TRL.

6. The broadband characteristic measurement method according to claim 4, characterized in that In the step of establishing the error model based on the at least one set of corrector measurement values, partial values in the at least one set of corrector measurement values are set according to the parameters of the corrector to establish the error model.

7. The broadband characteristic measurement method according to claim 4, wherein In the step of establishing the error model based on the at least one set of corrector measurement values, partial values of the at least one set of corrector measurement values are set according to the theoretical model to establish the error model.

8. The broadband characteristic measurement method according to claim 4, wherein In the step of using the corrector to be electrically connected to the other side of the signal converter to obtain the at least one set of corrector measurement values regarding the corrector by executing the correction program, it includes: Controlling the frequency conversion value of the signal converter; and Controlling the signal measurement device to perform frequency sweeping to obtain multiple sets of corrector measurement values regarding the corrector and the frequency conversion value.

Images