Measuring system for active load traction test and active load traction measuring method

Abstract

A measurement system for active load traction testing and an active load traction measurement method are described. The measurement system comprises a signal analysis module, a signal generator module, a control module and a DUT connector. The DUT connector may be connected to a device under test to receive an output signal of the device under test. The signal analysis module is connected to the DUT connector such that the signal analysis module receives a measurement signal corresponding to the output signal. The signal generator module is configured to generate a radio frequency (RF) test signal. The signal generator module is connected to the DUT connector such that the RF test signal is applied to the device under test. The signal analysis module is configured to digitize the measurement signal to obtain a digitized measurement signal. The control module is configured to control the signal generator module to generate the RF test signal based on the digitized measurement signal, based on known error parameters of an error model of the measurement system, and based on a desired reflection coefficient at a reference plane associated with the device under test.

Description

Technical Field

[0001] The present invention generally relates to a measurement system for active load-pull testing and also relates to an active load-pull measurement method. Background Art

[0002] Certain types of electronic devices under test (such as power amplifiers) need to be tested at a given impedance or within a given impedance range.

[0003] Typically, measuring instruments are constructed to measure at a specific impedance, usually 50 Ohms.

[0004] There are different techniques for adjusting the impedance. For example, the impedance presented to the device under test can be adjusted using a mechanical tuner, which is also known as the "passive load pull" technique.

[0005] As another example, the impedance presented to the device under test may be adjusted by measuring signals received from and transmitted to the device under test with two measurement receivers and by generating a signal applied to the device under test based on the measured signals, thereby presenting a desired impedance to the device under test. Summary of the Invention

[0006] Compared to usual measurement operations performed by a measuring instrument, the above-mentioned known techniques require additional hardware to be performed.

[0007] The object of the present invention is to provide a measurement system for active load-pull testing and an active load-pull measurement method having reduced hardware requirements.

[0008] According to the present invention, this problem is solved by a measurement system for active load pull testing. The measurement system includes a signal analysis module, a signal generator module, a control module and a DUT connector. The DUT connector can be connected to the device under test to receive the output signal of the device under test. The signal analysis module is connected to the DUT connector so that the signal analysis module receives a measurement signal corresponding to the output signal. The signal generator module is configured to generate a radio frequency (RF) test signal. The signal generator module is connected to the DUT connector to apply the RF test signal to the device under test. The signal analysis module is configured to digitize the measurement signal to obtain a digitized measurement signal. The control module is configured to control the signal generator module to generate the RF test signal based on the digitized measurement signal, known error parameters based on an error model of the measurement system, and an expected reflection coefficient at a reference plane associated with the device under test, wherein the error model describes the transmittance, reflectivity and / or directivity characteristics of the measurement system relative to the reference plane.

[0009] Therein and hereinafter, the term "module" is understood to describe suitable hardware, suitable software, or a combination of hardware and software that is configured to have a certain functionality.

[0010] The hardware may include, among other things, a CPU, GPU, FPGA, ASIC, or other types of electronic circuitry.

[0011] Furthermore, the term “error parameters” is understood to mean parameters of an error model, which describe the transmission, reflection and / or directivity properties of a part of the measurement arrangement comprising the reference plane.

[0012] The measuring system according to the invention is based on the idea of ​​utilizing known error parameters of an error model in order to set the required reflection coefficient at a reference plane.

[0013] For example, the known error parameters may have been determined in a previous calibration, which must be performed anyway in order to test the device under test.

[0014] Due to the use of error models, there is no need to measure the RF test signal generated by the signal generator module. Instead, it is sufficient to measure the output signal of the device under test.

[0015] In fact, the characteristics of the output signal at the reference plane can be determined based on the digitized measurement signal and based on the error model.

[0016] Furthermore, characteristics of the RF test signal transmitted at the reference plane may be determined based on the error model.

[0017] Since the characteristics of the output signal of the device under test and the RF test signal at the reference plane can be determined or more precisely calculated based on the error model, an appropriate RF test signal can be generated to present a desired reflection coefficient to the device under test at the reference plane.

[0018] In other words, by generating an RF test signal based on the digitized measurement signal, the known error parameters of the error model, and the expected reflection coefficient at the reference plane, a desired impedance can be presented to the device under test, i.e., a desired reflection coefficient is set at the reference plane.

[0019] Therefore, the measurement system according to the present invention requires fewer hardware components to perform active load-pull measurements.

[0020] In fact, in the signal analysis module, one measurement receiver is sufficient to set the desired reflection coefficient at the reference plane.

[0021] It should be noted that, of course, the measurement system may comprise more than one measurement receiver. However, this is not necessary for the measurement system according to the invention.

[0022] Furthermore, it is worth noting that the measurement system may still include a passive load-pull tuner, wherein the passive load-pull tuner may be interconnected between the device under test and the DUT connector, or may be disposed between the DUT connector and the signal analysis module.

[0023] Typically, the reference plane may correspond to the plane at which the device under test is connected to the DUT connector.

[0024] The cable can be connected to the DUT connector, with the reference plane located at the end of the cable facing away from the DUT connector. Thus, the error model describes the transmission, reflection, and / or directivity characteristics of a portion of the measurement system, including the DUT connector, the cable, and the reference plane. This improves the accuracy of calibration and / or subsequent measurements of the device under test by accounting for the connections within the measurement system, i.e., the cable, in the error model.

[0025] According to one aspect of the present invention, the RF test signal is a modulated signal. Therefore, the measurement system according to the present invention is also suitable for modulation S-parameter measurement.

[0026] Therein and hereinafter, the term "modulated signal" is understood to mean a signal having an amplitude, frequency and / or phase that varies over time. In other words, the modulated signal is not a pure continuous wave (CW) signal.

[0027] For example, the modulation signal may be a frequency swept signal, wherein the frequency of the CW signal is adjusted according to a predefined periodic function, such as a sawtooth function.

[0028] In an embodiment of the present invention, the error model is an n-term error model, in particular a 4-term error model or an 8-term error model. Therefore, the error model includes n error parameters that need to be determined in order to calibrate the measurement system, that is, the error terms include a total of n error parameters.

[0029] Therein, n is an integer greater than 1, in particular equal to or greater than 4.

[0030] For example, a 4-term error model can describe a single port.

[0031] As another example, an 8-term error model can describe two ports, particularly where one of the two ports is a driving port (i.e., forwarding a signal to an external electronic device, such as a device under test), and the other of the two ports is a receiving port (i.e., receiving a signal from an external electronic device, such as a device under test).

[0032] However, it will be appreciated that any other suitable error model may be used.

[0033] According to another aspect of the present invention, the error model is a two-port error model, wherein one port of the error model can be associated with the signal generator module and / or the signal analysis module, and the other port of the error model can be associated with the reference plane. The error model describes the transmission, reflection, and / or directivity characteristics within the portion of the measurement system modeled by the error model (i.e., the portion of the measurement system between the signal generator module and / or the signal analysis module and the reference plane).

[0034] In another embodiment of the invention, the error parameters are indicative of transmittance, reflectance and / or directivity properties of the measurement system obtained by calibration measurements performed by the signal generator module. In other words, the error terms of the error model are determined using the signal generator module as a calibration source.

[0035] In fact, any suitable calibration technique can be used to determine the error parameters. For example, a set of different calibration standards can be connected to the DUT connector in series at the reference plane, and a corresponding measurement can be performed for each different calibration standard.

[0036] In a specific example, the set of calibration standards may include an "open" calibration standard, a "short" calibration standard, and a "matched" calibration standard (also known as a "loaded" calibration standard). Thus, the calibration method used may be OSM-calibration, which is also known as SOL-calibration.

[0037] Another aspect of the present invention provides that the measurement system further includes an amplifier module, wherein the amplifier module is disposed downstream of the signal generator module and upstream of the DUT connector, and wherein the amplifier module is configured to amplify the RF test signal. In other words, the amplifier module is located between the signal generator module and the DUT connector.

[0038] To achieve the desired reflection coefficient at the reference plane, the RF test signal's signal level may need to exceed the maximum output level of the signal generator module. This means the maximum output level of the signal generator may not be sufficient. The amplifier module amplifies the RF test signal to the necessary signal level to achieve the desired reflection coefficient at the reference plane toward the device under test.

[0039] In fact, the amplifier module can be provided separately from the signal generator module.For example, the amplifier module can be integrated on a separate integrated circuit board, such as on a card, which can be inserted into the measuring instrument including the signal generator module.

[0040] In other words, by inserting the integrated circuit board including the amplifier module, the measuring instrument can be retrofitted with the amplifier module.

[0041] In particular, the control module is configured to set the amplification factor to be applied by the amplifier module based on the digitized measurement signal, based on known error parameters and / or based on a desired reflection coefficient. More precisely, the amplification factor can be set so that the desired reflection coefficient is presented to the device under test at the reference plane.

[0042] In an embodiment of the present invention, the measurement system further includes a switch module, wherein the switch module is configured to selectively couple the amplifier module to the signal path between the signal generator module and the DUT connector, or to bypass the amplifier module. Therefore, if the maximum output level of the signal generator module is sufficient to present a desired reflection coefficient to the device under test, the switch module can bypass the amplifier module. If the maximum output level of the signal generator module is insufficient to present the desired reflection coefficient to the device under test, the amplifier module can be coupled to the signal path between the signal generator module and the DUT connector via the switch module.

[0043] According to one aspect of the present invention, the measurement system further includes a directional coupling unit, wherein the directional coupling unit is connected to the DUT connector, the signal analysis module, and the signal generator module. The directional coupling unit is configured to forward an RF test signal from the signal generator module to the DUT connector, such that the RF test signal is applied to the device under test at the reference plane. Furthermore, the directional coupling unit is configured to forward an output signal of the device under test from the DUT connector to the signal analysis module.

[0044] In fact, the directional coupling unit may include an electrical connection connecting the DUT connector and the signal analysis module, or an electrical connection connecting the DUT connector and the signal generator module.

[0045] More precisely, the directional coupling unit can include an electrical connection connecting the DUT connector and the signal analysis module, while providing electromagnetic coupling between the DUT connector and the signal generator module (but no electrical connection between the DUT connector and the signal generator module). In this configuration, the signal-to-noise ratio (SNR) of the measured signal is enhanced because the direct electrical connection generally causes less attenuation than electromagnetic coupling.

[0046] Alternatively, the directional coupling unit can include an electrical connection connecting the DUT connector and the signal generator module, while providing electromagnetic coupling between the DUT connector and the signal analysis module (but no electrical connection between the DUT connector and the information analysis module). In this configuration, the SNR of the RF test signal transmitted to the reference plane is enhanced because the direct electrical connection generally causes less attenuation than electromagnetic coupling.

[0047] Another aspect of the present invention provides a directional coupling unit that is switchable between two operating modes, wherein the directional coupling unit includes an electrical connection connecting the DUT connector and the signal analysis module in a first operating mode, and wherein the directional coupling unit includes an electrical connection connecting the DUT connector and the signal generator module in a second operating mode. Thus, the measurement system can switch between different operating modes, providing a high signal-to-noise ratio (SNR) for the measurement signal or RF test signal.

[0048] In an embodiment of the present invention, the measurement system further comprises an input module, wherein the input module is configured to receive user input regarding the desired reflection coefficient. Therefore, the user can set the desired reflection coefficient via the input module.

[0049] The input module may comprise a user interface, in particular a graphical user interface, and appropriate input means, such as a keyboard, a computer mouse, buttons, a touch-sensitive display or any other suitable type of input means.

[0050] In a specific example, the input module can be a network module configured to receive user input via a network, in particular via a local area network, a wide area network and / or via the Internet. For example, the input module can receive user input as Standard Commands for Programmable Instruments (SCPI).

[0051] The input module may also be configured to forward user input regarding the desired reflection coefficient to the control module.

[0052] In another embodiment of the present invention, a measurement system includes a measurement instrument, wherein the measurement instrument includes a signal generator module, a signal analysis module and / or a DUT connector.

[0053] In fact, the measuring instrument may further include the above-mentioned directional coupling unit, the above-mentioned amplifier module and / or the above-mentioned input module.

[0054] For example, the measuring instrument may be a vector network analyzer, a signal analyzer, a spectrum analyzer, or an oscilloscope.

[0055] However, it should be understood that the measuring instrument may be configured as any other suitable type of measuring instrument.

[0056] According to the present invention, this problem is further solved by an active load-pull measurement method. The active load-pull measurement method comprises the following steps:

[0057] -Receive the output signal of the device under test;

[0058] - receiving, by the signal analysis module, a measurement signal corresponding to the output signal;

[0059] - The signal analysis module digitizes the measurement signal to obtain a digitized measurement signal;

[0060] determining, by the control module, the RF test signal to be generated based on the digitized measurement signal, known error parameters based on an error model of the measurement system, and based on an expected reflection coefficient at a reference plane associated with the device under test, wherein the error model describes transmission, reflection, and / or directivity characteristics of the measurement system relative to the reference plane;

[0061] - controlling the signal generator module by the control module to generate the determined RF test signal; and

[0062] -Apply the RF test signal to the device under test.

[0063] The above-described measurement system, in particular a measurement system according to any of the above-described variants, may be configured to perform an active load-pull measurement method.

[0064] For further advantages and features of the active load-pull measurement method, please refer to the above explanations about the measurement system, which also apply to the active load-pull measurement method and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated and better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings, in which:

[0066] - Figure 1 A first variant of the measuring system according to the invention is schematically shown;

[0067] - Figure 2 A second variant of the measuring system according to the invention is schematically shown;

[0068] - Figure 3 A flow chart showing an active load-pull measurement method according to the present invention; and

[0069] - Figure 4 Shows the description Figure 1 or Figure 2 Error model of a part of the measurement system. DETAILED DESCRIPTION

[0070] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments, wherein like numbers refer to like elements. Each embodiment described in the present disclosure is provided merely as an example or illustration and should not be construed as superior to or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise form disclosed.

[0071] For purposes of this disclosure, the phrase "at least one of A, B, and C" means, for example, (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when more than three elements are listed. In other words, the term "at least one of A and B" generally means "A and / or B," i.e., "A" alone, "B" alone, or "A and B."

[0072] Figure 1 A measurement system 10 is schematically shown that includes a measurement instrument 12 configured to perform active load-pull measurements on a device under test 14 .

[0073] exist Figure 1 In the exemplary embodiment shown, the measurement instrument 12 , which may be configured as a signal analyzer, spectrum analyzer, or oscilloscope, includes a single DUT connector 16 connected to the device under test 14 via a cable 18 .

[0074] However, it should be understood that the measuring instrument 12 may be configured as any other suitable type of measuring instrument including one or more ports, such as a vector network analyzer, a signal analyzer, a spectrum analyzer, or an oscilloscope having two or more ports.

[0075] Without limiting the generality, the following describes Figure 1 The exemplary embodiment shown.

[0076] The measuring instrument includes a signal analysis module 20 and a signal generator module 22 , each of which is connected to the DUT connector 16 .

[0077] Generally, the signal analysis module 20 is configured to digitize and analyze received signals, as will be described in more detail below.

[0078] For example, the signal analysis module 20 may be or include a vector signal analyzer.

[0079] The signal generator module 22 is configured to generate an RF test signal, as will be described in more detail below.

[0080] For example, the signal generator module 22 may be or include a vector signal generator and / or an arbitrary waveform generator.

[0081] The signal analysis module 20 and the signal generator module 22 are each connected to the DUT connector 16 via a directional coupling unit 24 .

[0082] Therein, the directional coupling unit 24 is configured to forward the output signal of the device under test 14 received by the DUT connector 16 to the signal analysis module 20 .

[0083] The directional coupling unit 24 is further configured to forward the RF test signal generated by the signal generator module 22 to the DUT connector 16 , so that the RF test signal is forwarded to the device under test 14 via the DUT connector 16 and the cable 18 .

[0084] exist Figure 1 In the exemplary embodiment shown, directional coupling unit 24 includes an electrical connection between DUT connector 16 and signal analysis module 20 , and an electromagnetic coupling between DUT connector 16 and signal generator module 22 .

[0085] Alternatively, if Figure 2 As shown, the directional coupling unit 24 may include an electrical connection connecting the DUT connector 16 and the signal generator module 22 , and an electromagnetic coupling between the DUT connector 16 and the signal analysis module 20 .

[0086] Optionally, an amplifier module 26 may be provided between the signal generator module 22 and the directional coupling unit 24 , wherein the amplifier module 26 is configured to amplify the RF test signal generated by the signal generator module 22 with an adjustable amplification factor.

[0087] Additionally, a switch module 28 may be provided, wherein the switch module 28 is configured to selectively couple the amplifier module 26 into the signal path between the signal generator module 22 and the DUT connector 16 , or to bypass the amplifier module 26 .

[0088] In fact, the amplifier module 26 and / or the switch module 28 may be provided separately from the signal generator module 22 .

[0089] For example, the amplifier module 26 and / or the switch module 28 may be integrated on a separate integrated circuit board, such as a card, which may be inserted into the measuring instrument 12 .

[0090] Therefore, the measuring instrument 12 can be retrofitted with an amplifier module 26 and / or with a switch module 28 .

[0091] The measurement instrument 12 also includes a control module 30 connected to the signal analysis module 20 and the signal generator module 22 .

[0092] Optionally, the control module 30 may be connected to the directional coupling unit 24 , the amplifier module 26 and / or the switch module 28 .

[0093] In fact, the control module 30 can be configured to control the directional coupling unit 24 to respectively Figure 1 and Figure 2 Switches between the two operating modes shown.

[0094] exist Figure 1 In the first operating mode shown, the directional coupling unit 24 includes electrical connections between the DUT connector 16 and the signal analysis module 20 .

[0095] exist Figure 2 In the second operating mode shown, the directional coupling unit 24 includes electrical connections between the DUT connector 16 and the signal generator module 22 .

[0096] Alternatively or additionally, the control module 30 may be configured to adjust the amplification factor of the amplifier module 26 .

[0097] Alternatively or additionally, the control module 30 may be configured to control the switch module 28 to couple the amplifier module 26 into the signal path between the signal generator module 22 and the DUT connector 16 , or to bypass the amplifier module 26 .

[0098] Further functionality of the control module 30 will be described in more detail below.

[0099] The measurement instrument 12 may further include an input module 31 configured to receive user input.

[0100] For example, the input module 31 may comprise a user interface, in particular a graphical user interface, and appropriate input means, such as a keyboard, a computer mouse, buttons, a touch-sensitive display or any other suitable type of input means.

[0101] In another example, the input module 31 may be a network module configured to receive user input via a network, in particular via a local area network, a wide area network and / or via the Internet. For example, the input module 31 may receive user input as Standard Commands for Programmable Instruments (SCPI).

[0102] The input module 31 is connected to the control module 30 , so that user input received by the input module 31 is forwarded to the control module 30 .

[0103] The device under test 14 includes an output port 32 connected to the DUT connector 16 via the cable 18 .

[0104] More precisely, the device under test 14 is connected to the cable at a reference plane 34 located at the end of the cable 18 facing away from the DUT connector 16 .

[0105] Typically, the device under test 14 is configured to generate an output signal that is forwarded to the DUT connector 16 via the output port 32 and the cable 18 .

[0106] For example, the device under test 14 may be a mobile communication device, such as a smartphone or a tablet computer.

[0107] Although Figure 1 and Figure 2 In FIG. 1 , the device under test 14 is shown as a single-port device, but it should be understood that the device under test 14 can also be built as a multi-port device.

[0108] For example, the device under test 14 may be configured to receive an input signal via an input port and process the received input signal to generate an output signal.

[0109] In certain examples, the device under test 14 may be an amplifier, a mixer, a filter, or any other type of electronic multi-port device.

[0110] The measurement system 10, and in particular the measurement instrument 12, is configured to perform an active load-pull measurement method, which will be referred to hereinafter. Figure 3 Describe, Figure 3 A flow chart of the active load-pull measurement method is shown.

[0111] If calibration of the measuring instrument 12 has not yet been performed, the measuring instrument 12 is calibrated, thereby determining error parameters of the error model (step S1 ).

[0112] The error parameters may be determined using any suitable calibration technique. For example, a set of different calibration standards may be serially connected to the DUT connector at a reference plane, and corresponding measurements may be performed for each different calibration standard.

[0113] In a specific example, the set of calibration standards may include an "open" calibration standard, a "short" calibration standard, and a "matched" calibration standard (also known as a "loaded" calibration standard). Thus, the calibration method used may be OSM-calibration, which is also known as SOL-calibration.

[0114] During the calibration process, the signal generator module 22 is used as a calibration source, that is, the RF test signal used for calibration is generated by the signal generator module 22 .

[0115] Typically, the error model or more precisely the error parameters of the error model describe the reflective, transmissive and / or directivity properties of a portion of the measuring system 10 between the reference plane 34 on the one hand and the signal analysis module 20 and the signal generator module 22 on the other hand.

[0116] Figure 4 An exemplary error model is shown. In this exemplary case, the multi-port error model is a multi-port error model with four error parameters e 22 、e 33 、e 32 and e 23 The 2-port error model is a 4-term error model.

[0117] However, it will be appreciated that any other suitable multi-port error model may be used.In fact, the multi-port error model may be any suitable n-term error model comprising n error parameters.

[0118] Error term e 22 、e 33 、e 32 and e 23 The error model describes reflections of hardware components that are part of the measurement system 10 (also called “load matching”), transmission between the signal generator module 22 and the signal analysis module 20 (also called “directivity”), transmission between the reference plane 34 and the signal analysis module 20 (also called “forward tracking”), and transmission between the signal generator module 22 and the reference plane 34 (also called “reverse tracking”), respectively.

[0119] The multi-port error model can be expressed as a matrix

[0120] An output signal is received from the device under test (step S2).

[0121] exist Figure 4 In FIG. 3 , the output signal of the device under test 14 is represented as “a”, that is, the signal “a” corresponds to the output signal of the device under test 14 at the reference plane 34 .

[0122] The signal analysis module 20 receives a measurement signal corresponding to the output signal (step S3 ).

[0123] exist Figure 4 In the example, the measurement signal is represented by “b meas ”.

[0124] The output signal a is forwarded to the signal analysis module 20 via the cable 18 , the DUT connector 16 and the directional coupling unit 24 , such that the output signal changes due to the reflective, transmissive and directive properties of the cable 18 , the DUT connector 16 and the directional coupling unit 24 .

[0125] Therefore, the measurement signal b at the signal analysis module 20 is meas Typically different from the output signal a at the reference plane 34 .

[0126] Measurement signal b meas The signal is digitized by the signal analysis module 20 to obtain a digitized measurement signal (step S4).

[0127] The digitized measurement signal is then forwarded to the control module 30 .

[0128] The RF test signal a generated by the signal generator module 22meas is determined by the control module 30 based on known error parameters of the error model and based on the expected reflection coefficient Γ at the reference plane 34 (step S5).

[0129] The expected reflection coefficient Γ describes the actual reflection coefficient presented to the device under test 14 at the reference plane 34, ie, including active load pulling as described below.

[0130] It should be emphasized that the expected reflection coefficient Γ is not equal to the load matching e 22 .

[0131] The desired reflection coefficient Γ may be received from the user via the input module 31 and may be forwarded to the control module 30. In other words, the user may set the desired reflection coefficient via the input module 31.

[0132] As described below, the RF test signal a to be generated can be determined meas .

[0133] Since the error model The error parameters of are known and can therefore be calculated based on the digitized measurement signal, i.e., based on the measurement signal b meas , and based on the known error parameter e 22 、e 33 、e 32 and e 23 To determine the output signal a received from the device under test 14 at the reference plane 34 .

[0134] The RF test signal b to be applied to the device under test 14 at the reference plane 34 is given by b=Γ·a, where Γ and a are known.

[0135] Since the error model The error parameters of are known, so the RF test signal a to be generated can be determined based on b = Γ·a and the error parameters based on the error model. meas .

[0136] Among them, the determined RF test signal a meas It can be a modulated signal.

[0137] The signal generator module 22 is controlled by the control module 30 to generate the determined RF test signal a meas (Step S6).

[0138] RF test signal a meas It is forwarded to the reference plane 34 via the directional coupling unit 24 , the DUT connector 16 and the cable 18 .

[0139] If the maximum output level of the signal generator module is insufficient to obtain the RF test signal b at the reference plane 34, the RF test signal a generated by the signal generator module 22 meas The signal can be amplified by the amplifier module 26 .

[0140] In particular, the control module 30 may control the amplifier module 26 to set an appropriate amplification factor.

[0141] Alternatively or additionally, the control module 30 may control the switch module 28 to couple the amplifier module 26 into the signal path between the signal generator module 22 and the DUT connector 16 .

[0142] With the generated RF test signal a meas A corresponding RF test signal b is applied to the device under test 14 at the reference plane 34 (step S7).

[0143] Therefore, a desired reflection coefficient Γ is presented to the device under test 14 at the reference plane 34 .

[0144] In other words, a desired impedance is presented to the device under test 14 at the reference plane 34 .

[0145] While the RF test signal is being applied to the device under test, further measurements may be performed on the output signal received from the device under test 14 (step S8).

[0146] Further measurements may be performed by the signal analysis module 20 .

[0147] Thus, the performance of the device under test 14 may be evaluated while presenting the device under test 14 with a desired reflection coefficient corresponding to an expected impedance.

[0148] In other words, active load-pull measurements can be performed.

[0149] Certain embodiments disclosed herein, particularly corresponding module(s) and / or unit(s), utilize circuitry (e.g., one or more circuits) to implement the standards, protocols, methods, or techniques disclosed herein, operatively couple two or more components, generate information, process information, analyze information, generate signals, encode / decode signals, convert signals, transmit and / or receive signals, control other devices, etc. Any type of circuitry may be used.

[0150] In an embodiment, the circuit system includes, among other things, one or more computing devices such as a processor (e.g., a microprocessor), a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system on a chip (SoC), or the like, or any combination thereof; and may include discrete digital or analog circuit elements or electronic devices, or a combination thereof. In an embodiment, the circuit system includes hardware circuit implementations (e.g., implementations in analog circuit systems, implementations in digital circuit systems, and the like, and combinations thereof).

[0151] In an embodiment, the circuit system includes a combination of circuits and a computer program product having software or firmware instructions stored on one or more computer-readable memories, the instructions working together to cause the apparatus to perform one or more protocols, methods, or techniques described herein. In an embodiment, the circuit system includes circuits that require software, firmware, and the like to operate, such as, for example, a microprocessor or portion of a microprocessor. In an embodiment, the circuit system includes one or more processors or portions thereof, and accompanying software, firmware, hardware, and the like.

[0152] This application may refer to quantities and numbers. Unless otherwise specified, such quantities and numbers should not be considered as limiting, but rather examples of possible quantities or numbers associated with this application. In addition, in this regard, this application may use the term "plurality" to refer to quantities or numbers. In this regard, the term "plurality" means any number greater than one, for example, two, three, four, five, etc. The terms "approximately," "approximately," "close to," etc., mean plus or minus 5% of a specified value.

Claims

1. A measurement system for active load-pull testing, wherein: The measurement system (10) includes a signal analysis module (20), a signal generator module (22), a control module (30) and a DUT connector (16). wherein the DUT connector (16) is connectable to the device under test (14) to receive an output signal of the device under test (14), wherein the signal analysis module (20) is connected to the DUT connector (16) such that the signal analysis module (20) receives a measurement signal corresponding to the output signal, The signal generator module (22) is configured to generate a radio frequency (RF) test signal. wherein the signal generator module (22) is connected to the DUT connector (16) so that the RF test signal is applied to the device under test (14), The signal analysis module (20) is configured to digitize the measurement signal to obtain a digitized measurement signal, and The control module (30) is configured to control the signal generator module (22) to generate the RF test signal based on the digitized measurement signal, known error parameters based on an error model of the measurement system (10), and based on an expected reflection coefficient at a reference plane (34) associated with the device under test (14), wherein the error model describes the transmission, reflection and / or directivity characteristics of the measurement system (10) relative to the reference plane (34).

2. The measurement system according to claim 1, wherein: The RF test signal is a modulated signal.

3. The measuring system according to any one of the preceding claims, wherein The error model is an n-term error model, in particular a 4-term error model or an 8-term error model.

4. The measuring system according to any one of the preceding claims, wherein The error model is a two-port error model.

5. The measuring system according to any one of the preceding claims, wherein The error parameters are indicative of transmissive, reflective and / or directional properties of the measurement system (10) obtained by calibration measurements performed by the signal generator module (22).

6. The measuring system according to any one of the preceding claims, wherein: The measurement system (10) further includes an amplifier module (26), wherein the amplifier module (26) is disposed downstream of the signal generator module (22) and upstream of the DUT connector (16), and wherein the amplifier module (26) is configured to amplify the RF test signal.

7. The measurement system according to claim 6, wherein: The control module (30) is configured to set an amplification factor to be applied by the amplifier module (26) based on the digitized measurement signal, based on the known error parameter and / or based on the expected reflection coefficient.

8. The measurement system according to claim 6 or 7, wherein: The measurement system (10) further includes a switch module (28), wherein the switch module (28) is configured to selectively couple the amplifier module (26) into a signal path between the signal generator module (22) and the DUT connector (16), or to bypass the amplifier module (26).

9. The measuring system according to any one of the preceding claims, wherein: The measurement system (10) further includes a directional coupling unit (24), wherein the directional coupling unit (24) is connected to the DUT connector (16), the signal analysis module (20), and the signal generator module (22).

10. The measurement system according to claim 9, wherein: The directional coupling unit (24) includes an electrical connection connecting the DUT connector (16) and the signal analysis module (20), or an electrical connection connecting the DUT connector (16) and the signal generator module (22).

11. The measurement system according to claim 9 or 10, wherein: The directional coupling unit (24) is switchable between two operating modes, wherein the directional coupling unit (24) includes an electrical connection connecting the DUT connector (16) and the signal analysis module (20) in a first operating mode, and wherein the directional coupling unit (24) includes an electrical connection connecting the DUT connector (16) and the signal generator module (22) in a second operating mode.

12. The measuring system according to any one of the preceding claims, wherein The measurement system (10) further comprises an input module (31), wherein the input module (31) is configured to receive user input regarding the desired reflection coefficient.

13. The measuring system according to any one of the preceding claims, wherein: The measurement system (10) includes a measurement instrument (12), wherein the measurement instrument (12) includes the signal generator module (22), the signal analysis module (20) and / or the DUT connector (16).

14. The measurement system according to claim 13, wherein: The measuring instrument (12) is a vector network analyzer, a signal analyzer, a spectrum analyzer or an oscilloscope.

15. An active load-pull measurement method, comprising the following steps: - receiving an output signal of the device under test (14); - receiving, by a signal analysis module (20), a measurement signal corresponding to the output signal; - The signal analysis module (20) digitizes the measurement signal to obtain a digital The measurement signal of - a control module (30) based on the digitized measurement signal, known error parameters of the error model of the measurement system (10) and parameters associated with the device under test (14); The RF test signal to be generated is determined based on an expected reflection coefficient at a reference plane (34), wherein the error model describes the transmission error of the measurement system (10) relative to the reference plane (34). radioactive, reflective and / or directional properties; - controlling the signal generator module (22) by the control module (30) to generate the determined RF test signal; and - applying the RF test signal to the device under test (14).

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