Eliminating the effects of instability in the measurement system

Abstract

The present invention provides a measurement system and method that eliminates the influence of instability in the measurement system while measuring at least one S-parameter of a device under test. [Solution] The method includes identifying the location of instability in the time domain of the measurement system, first determining the characteristics of the measurement system, determining the change in the characteristics of the measurement system while connected to the device under test (DUT), and compensating for the determined change in the characteristics of the measurement system while connected to the DUT by removing the effect of the determined change on the measurement of at least one S-parameter of the DUT.

Description

[Background technology]

[0001] A vector network analyzer (VNA) is used to analyze the frequency range. It is used to measure radio frequency (RF) signals in the region. NA (Numerical Analysis) is particularly important due to the nature of ratio measurement, and is used for devices under test (DUT). This enables accurate and stable measurement of the S-parameters of ). The UT consists of a VNA, a test cable, and optional components such as adapters, connectors, and switches. It connects to a VNA system equipped with a connection device. However, some users D uses extremely high accuracy that surpasses the stability provided by conventional VNA systems. I would like to characterize UT.

[0002] Various conventional calibration techniques have been used to improve the accuracy of S-parameter measurements using VNA systems. These calibration techniques have been developed for this purpose. However, these calibration techniques only improve accuracy during the initial calibration. No. Therefore, the characteristics of the VNA system, for example, the test cable and connection device If the calibration changes due to environmental fluctuations, the altered characteristics will affect the accuracy of subsequent measurements. This can reduce the stability of the VNA system after the characteristics have changed. The motor needs to be recalibrated.

[0003] However, recalibration requires removing the VNA system from the DUT and connecting it to a calibration reference. This requires a lot of effort and can be difficult and time-consuming. As a result, the test cable and It is necessary to move other connections, which can cause instability in the VNA system. Other conventional calibration techniques are easier to implement and can avoid instability in a different way. However, it requires special hardware, and this hardware may not be available. They can also be expensive to purchase. One example of such recalibration techniques is Keysight T CalPod calibration refresh module available from echnologies, Inc. This is provided by CalPod. However, this technique is not available in CalPod. The VNA measurement system needs to include additional hardware specific to it, and this hardware A is expensive and requires complex additional initial calibration. Furthermore, recalibration requires DU T must be electrically disconnected.

[0004] The exemplary embodiments are best understood by reading them in conjunction with the attached drawings, as described below. It is important to emphasize that various features are not necessarily depicted to scale. In reality, To clarify the considerations, dimensions may be arbitrarily enlarged or reduced. Applicable and practical In any practical use, the same reference number points to the same element. [Brief explanation of the drawing]

[0005] [Figure 1] This is a simplified block diagram showing a typical embodiment of a measurement system that eliminates the influence of instability when measuring at least one S-parameter of a device under test (DUT). [Figure 2] This is a simplified flowchart illustrating a method for eliminating the effects of system instability used to measure at least one S-parameter of a DUT, according to a typical embodiment. [Figure 3A] This graph shows the DUT's return loss response without removing the effects of measurement system instability. [Figure 3B]This graph shows the return loss response of the DUT with the effects of measurement system instability removed, according to a typical embodiment. [Modes for carrying out the invention]

[0006] The following detailed description, for illustrative purposes only and without limitation, illustrates one embodiment of this teaching. To ensure a complete understanding, a representative embodiment disclosing specific details is described. To avoid obscuring the description of typical embodiments, known systems and devices Descriptions of materials, operation methods, and manufacturing methods may be omitted. Nevertheless, Systems, devices, materials, and methods within the scope of the vendor's understanding are within the scope of this instruction. , may be used according to representative embodiments. The terms used herein are This is intended solely to describe specific embodiments and is not intended to limit them. It should be understood that the defined terms, in addition to their scientific and technical meaning, are important. This has meaning that is generally understood and accepted in the technical field of this instruction.

[0007] In order to describe various elements or components, the first, second, third, Terms such as these may be used, but these elements or components are not defined by these terms. It should be understood that these terms should not be limited. These terms refer to a certain element or component. It is used solely to distinguish it from other elements or components. Therefore, it is discussed below. The first element or component may be modified without departing from the teachings of this disclosure to form the second element or component. These can be called elements.

[0008] The terms used herein are intended solely to describe specific embodiments. It is not intended to be limiting. When used in this specification and the appended claims the singular forms of the terms "a", "an", "the" and "said" include both the singular and plural forms, unless the context clearly dictates otherwise. Further, the terms "comprises", "comprising" and / or similar terms, when used in this specification, specify the presence of the recited features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or groups thereof. When used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. Unless otherwise stated, when an element or component is said to be "connected to", "coupled to" or "adjacent to" another element or component, it can be directly connected or coupled to the

[0009] said other element or component, or there may be intervening elements or components. That is, these terms and similar terms include cases where one or more intermediate elements or components may be utilized to connect two elements or components. However, when an element or component is said to be "directly connected to" another element or component, this includes only cases where the two elements or components are connected to each other without using any intermediate or intervening element or component.

[0010] ​​​Therefore, this disclosure does not include various aspects, embodiments and / or specific features or sub-features thereof. Through one or more of the components, one of the advantages specifically mentioned below The purpose is to clarify the above. This is for explanatory purposes and is not limited, but this instruction To fully understand one embodiment, an exemplary implementation disclosing specific details... The state is described. However, it deviates from the specific details disclosed herein. However, other embodiments not inconsistent with this disclosure are still within the scope of the appended claims. Furthermore, in order to avoid obscuring the description of exemplary embodiments, well-known apparatus and methods are described. The terminology may be omitted. Such methods and apparatus are within the scope of this disclosure.

[0011] Various embodiments address the uncertainty of the measurement system while measuring the device under test (DUT). This concerns methods and systems for eliminating qualitative influences. The measurement system includes measuring instruments and... It includes a connection circuit for connecting measuring instruments to the DUT. The measuring instruments are, for example, vector nets. It can be used as a reflectometer such as a network analyzer (VNA) or network analyzer. This embodiment does not require disconnecting the DUT or repeating the initial calibration step. To re-establish effective calibration of the measuring surface of measuring instruments, thereby improving the operation of the measuring system. We guarantee that the characteristics will not be affected by changes caused by environmental fluctuations and other factors.

[0012] According to a typical embodiment, the initial characteristics of the measurement system are determined, and the measurement system is set to DUT. Connect and measure at least one S-parameter of the DUT, for example, connected to the DUT During this time, the initial characteristics of the measurement system are determined, and the measurement system while connected to the DUT is determined. A method is provided to compensate for the required changes in the initial characteristics of the unit. The measurement system's correction is enhanced. This enables highly stable measurement of the DUT. This solution is achieved in the post-calibration measurement system. The accuracy of S-parameter measurements is maintained by compensating for the changes in these parameters. Without moving the test cable of the fixed system, and without needing to connect it to the calibration standard. It can be extracted using the connected DUT. Additionally, no additional hardware is required. It will not be done.

[0013] Figure 1 shows at least one S-pattern of the device under test (DUT) according to a typical embodiment. Simplified block illustrating a measurement system that eliminates the effects of instability while measuring the lamometer. This is a diagram.

[0014] Referring to Figure 1, the measurement system 100 includes a measuring instrument 110 and a DU (Digital Access Control) for the measuring instrument 110. It includes a connection circuit 165 that connects to T160. The measuring instrument 110 is, for example, a VNA, It is possible to measure the reflectance meter, such as a network analyzer, or the S-parameter of the DUT160. It can be any other possible device. The connection circuit 165 is connected to the test cable 161. (For example, coaxial cables, waveguides, striplines, microstrips) and typical It comprises other connected devices indicated by switch 162. However, for example, Other types of connection devices such as plugs and connectors may be included. Measurement System 1 00 further comprises a processing unit 150. This processing unit is as will be apparent to those skilled in the art. It can be included in the measuring device 110, or it can be separated from the measuring device 110 and connected to a wired network. It can also be connected via a web connection or a wireless network connection. Measurement system 100 For example, to measure the S-parameters of DUT160, connect to DUT160 It is possible.

[0015] The measuring instrument 110 of the measuring system 100 is a representative first port 101 to the mth port. Multiple ports on the measurement surface 105 that receive RF measurement signals, as indicated by 102 Prepare. Here, m is a positive integer representing the total number of ports on the measuring instrument 110. In this example, the first port 101 measures the S-parameter of the DUT 160 on the DUT measurement surface 106. For the purpose of measuring the signal strength, one port of the DUT160 is connected via connection circuit 165. It appears to be connected. However, the DUT160 has multiple ports. It is understood that this is possible (for example, a 2-port device), and in this case, the measuring instrument At least one additional port of 110 (for example, port 102 of the mth) To be connected to the corresponding additional port of the DUT160 performing the measurement, Yes. Eliminate the effects of instability in the measurement system 100 while measuring DUT160. The process described herein for this purpose involves the other ports of the measuring instrument 110 and the DUT The same applies to each of the connection circuits between 160 and the other device.

[0016] The first port 101 and the second port 102 receive radio frequencies (RF) from the DUT160. ) This is the input to the corresponding channel (not shown) that receives and measures the measurement signal. As is known to those skilled in the art, for example, dual couplers, dual mixers and It also features a dual analog-to-digital converter (ADC). The digitized measurement signal can be provided to the processing unit 150. For example, T150 indicates the instability of the measurement system 100 while measuring DUT160. Perform additional processing, including removing the effects.

[0017] In the illustrated embodiment, the processing unit 150 includes a processor device 155 and a memory 1 It includes 56, interface 157, and display 158. Processor device Chair 155, along with memory 156, measures the DUT 160 while the measurement system 1 At least a portion of the method for eliminating the effects of 00 instability is implemented and discussed below in Figure 2. Configure to execute and / or control all or part of the steps of the process shown. This is possible. In various embodiments, the processor device 155 is hardware, software Wear, firmware, wiring logic circuits, or any combination thereof One or more computer processors that use digital signal processors (DSPs) (Gital signal processor), Central Processing Unit (CPU), Graphics processing unit (GPU), remote application Application Program Interface (API), Field-programmable gate array (FPGA), Application-specific integrated circuits (ASICs), or These combinations may be included. Processor device 155 is specified herein Computer-readable code that enables the execution of various functions (e.g., software) The processing memory that stores the software module, software engine, etc. You can prepare for it.

[0018] The processing memory and any other memory (and database) described herein are , various types of random access memory (RAM), read-on This can be read-only memory (ROM) and / or other storage media. These include flash memory and electrically programmable read-only memory (EPROM). (electrically programmable read-only memory), electrically erasable programmable read Read-only memory (EEPROM: electrically erasable and programmable read-only memory) (ory), Compact Disk Read-On Memory (CD-ROM: compact disk read onl (y memory), digital versatile disk (DVD), register, Latch, flip-flop, hard disk, removable disk, tape, floppy Blu-ray Disc, or Universal Serial Bus (USB:univer SAL serial bus) driver, or any other form of storage medium known in the art This includes bodies. These are tangible and non-transient (compared to, for example, transient propagating signals). The memory may be volatile or non-volatile, without departing from the scope of this instruction. Secure and / or encrypted, unsecure and / or encrypted It can be treated as if it does not exist. As mentioned above, memory 156 is distributed across the network Processing memory and multiple memory and databases, including connected memory and databases. Represents one or more memory and databases, including a database.

[0019] Interface 157 is provided by processor device 155 and / or memory 156 Provide the outputted information and data to the user and / or the information and data entered by the user Includes a user interface and / or network interface for receiving data. This is possible. In other words, interface 157 allows the user to input data and to control or operate the manner of the process for measuring periodic RF signals in the frequency domain. This enables the processor device 155 to control or operate the user's actions. It also makes it possible to display. Interface 157 is a port, disk drive, wireless amplifier. It may include one or more of the following: a tenor, or other types of receiver circuit mechanisms. Face 157 is used for, for example, mice, keyboards, trackballs, joysticks. Microphone, video camera, touchpad, touchscreen, microphone One or more devices such as voice or gesture recognition devices that capture sound or gestures by a phone or video camera. - Further interfaces can be connected.

[0020] Display 158 is, for example, a computer monitor, television, or LCD display (L CD (liquid crystal display), Organic light-emitting diode (OLED: organic light emitter) Cathode ray tubes (C) RT: Cathode Ray Tube) Monitor such as a display, or an electronic whiteboard. This is possible. The display 158 and / or processor device 155 have one or more displays. It can be equipped with a display interface, in which case the display 158 is, A graphical user interface for displaying information on the system and receiving information from users. It can provide a graphical user interface (GUI).

[0021] In one embodiment, in the DUT interface of the measurement system 100 or DU Initial calibration can be performed before the T interface. This is obvious to those skilled in the art. As shown, it is connected to a calibration reference (not shown) via the test cable 161 and switch 162. Standards performed using one or more of the first port 101 to the mth port 102 This is a type of calibration. For example, initial calibration can be factory calibration. Factory calibration is a test calibration. This is done before the cable, i.e., without the test cable, but if there is no factory calibration, the initial Period calibration can be performed at the DUT interface. Test calibration can also be performed, for example, at the DU interface. Measurement surface 105, i.e., the connected DUT, for measuring the S-parameters of T160. This is performed at the DUT interface with the 160. Test calibration is performed, for example, at a narrower frequency. Several ranges, wider frequency ranges, different power levels and / or different points, etc. This is performed across specific test stimulus conditions, which may differ from the initial calibration stimulus conditions. The calibration can be performed before or at the same time as the test calibration. Furthermore, the DUT test stimulus (e.g., frequency range, number of points) is used to determine the duration of the subject's instability. Sufficient to calculate a time-domain response with sufficient range and resolution to determine the target position In such cases, the test calibration can be the same as the initial calibration. The test initialization is performed under initial calibration and test calibration conditions. In another embodiment, D The initial calibration of the UT interface can be omitted without deviating from the scope of this instruction. In this case, uncalibrated measurements are used.

[0022] Following calibration, the measurement system 100 performs measurements of one or more S-parameters, etc., on the DUT 16. It is used to measure 0. However, the measuring system 100 is used for ambient temperature and The measurement system 100 performs measurements as a result of changing test conditions such as changes in pressure. This includes various instabilities that can change in between. These instabilities include, for example, ambient temperature, ambient pressure, and test results. Measuring instruments that respond to changing test conditions such as the movement of cable 161 and / or external vibrations. Frequency drift and impedance drift in 110 (reflectometer), test cable 16 Drift and instability in 1, and / or, for example, RF switches, adapters and cords Variation errors in other components within the connection circuit 165, such as connectors, which change over time. This is a characteristic of the measurement system 100. Instability is a characteristic of the measurement by the measurement system 100. This affects accuracy. For example, from the DUT160 measured by the measurement system 100 Return loss (S 11 The response will change due to instability in the measurement system 100. It looks like it.

[0023] The instability of the measurement system 100 is detected by the processing unit 150 in the time domain. It is identified at the target location and has a corresponding physical location. Figure 1 shows the measurement system 100. The instability in the example shown is between the first port 101 and DUT 160, curves 171 and 172. , as shown by 173 and 174. In detail, the first port 101 is The introduced instability is shown by curve 171, and the instability introduced by switch 162 Stability is shown by curve 172, and instability introduced by test cable 161. These are shown by curves 173 and 174. The temporal positions of these instabilities are as follows: Test cables, switches, adapters, and connectors, etc., that are known to have tolerance errors. This can be determined based on the physical position of the components and / or by measuring the DUT160. This can be determined in the time-domain trace of the response. For example, the temporal instability The position is the frequency response S 11 Using time-domain conversion of the measurement, time-domain conversion caused by instability This can be determined by looking for changes in the race. The points where instability occurs... To verify this, we will examine the time-domain response in front of the DUT160 over a long period of time. This is possible. In some cases, the DUT160 can be measured over several days or weeks. However, even observations of a few minutes or a few hours may be sufficient to determine the location of the instability. There are also others.

[0024] While measuring at least one S-parameter of DUT160, the measurement system 100 To eliminate the effects of instability, the processor device 155 in the processing unit 150 This executes the instructions stored in memory 156. These instructions are for the measurement system 100. First, determine at least one characteristic, and this first determined at least one characteristic The values ​​are stored in memory 156, and the measurement is performed while the DUT160 remains connected. To determine the change in at least one characteristic of stem 100 and to continue contact with DUT160 The processor compensates for the desired change in at least one characteristic while it is running. The device 155 performs the measurement. The measurement system 100 eliminates the effects of instability during measurement. Then, measure at least one S-parameter of the DUT160 using a known method.

[0025] More specifically, the characteristics of the measurement system 100 are initially determined independently of the DUT 160. This is then stored in a representative memory 156. The characteristics are, for example, the DUT of the first port 101. 160 return loss response or voltage standing wave ratio (VSWR) This can be used as a measurement of the response. This measurement can be performed in front of the DUT160 (for example, Goethe). Gating time (gating time) is the time domain portion that occurs within a span of 180. However, this is the same as what is being done to test DUT160. This is possible. The characteristics of the measurement system 100 are that the DUT160 is attached to the measurement system 100. It can be determined first, regardless of whether it has been blocked or not. In particular, the return loss response is As is clear to the vendor, for the first port 101, S 11 As shown by, the second point Regarding the (unknown) part, S 22 As shown, regarding the third port (not shown) is S 33 This is indicated by [the specified method], and the same applies to other ports.

[0026] In one embodiment, the characteristics are as described above, curves 171, 172, 173 and 1 One or more instabilities in the time domain of the measurement system 100, such as those indicated by 74. It is first determined by identifying the temporal position of the instability. The gating time span of 180 that covers the position is time-domain gating. The gate-controlled response (gated re) of the measurement system 100 is set using gate control. The response (e.g., return loss response or VSWR response) is a gate in the frequency domain. Measurements are taken over a controlled time span of 180. The gating time span of 180 is: In order to correct instability in both the measuring instrument 110 and the connecting circuit 165, the measuring instrument From inside 110 (first port 101), any point before the connection to DUT160 It extends to the gate. The measured, gate-controlled response is obtained from the first measurement system 1. This is a characteristic of 00 and is stored in the representative memory 156. In the illustrated example, the first one to be obtained is The characteristics described are: the first port 101 connected to the DUT160, the test cable 161 and Includes the instability of switch 162.

[0027] Setting a gating time span of 180 using time domain gating is It is well known to vendors. Generally, time-domain gating is used in a portion of the time domain. Select the target area of ​​the measurement system 100, and time in the selected target area. The process involves determining the regional response and removing unwanted responses outside the selected target area. This includes the following. The response in the selected target area is, for example, the inverse fast Fourier transform (IFF). This can be provided in the frequency domain by performing T). Regional gating effectively multiplies the time-domain response by a value of 1 in the target area, and the target area Outside the rear, we effectively multiply by 0, thereby isolating and gating the time-domain response. Provides a corresponding frequency-domain response free from the influence of unwanted external responses with a time span of 180. Therefore, time-domain gating is used to measure the response of the DUT160 in the measurement system 100. It isolates the instability response, and therefore, to determine the characteristics first or otherwise, DU There is no need to disconnect the T160.

[0028] After the initial characteristics of the measurement system 100 are stored, the measurement system 100 is D Changes in characteristics are required while the UT160 is physically and electrically connected. The change arises from instability within the measurement system 100. In one embodiment, the change occurs in the DUT While connected to 160, the same gating time span 180 in the frequency domain This can be determined by measuring the gate-controlled response of another measurement system 100. The measured gate-controlled response was then determined from the measurement system 100. This is a characteristic, and this response can also be stored, for example, in a typical memory 156. Next The change in characteristics is compared to the initially determined characteristics that were stored in memory. It can be determined by comparison.

[0029] Changes in characteristics can be detected without disconnecting the DUT160 from the measurement system 100, and the calibration base The instrument can be obtained without having to reconnect it to the measurement system 100. Changes in its properties can be triggered by various events. The change in characteristics is observed between operations to determine the change in characteristics, before each measurement of the DUT160. It can also be calculated periodically at intervals, and / or by the user's choice of timing. It can also be determined according to the ming. Alternatively, the change in characteristics can be determined, for example, by exceeding a predetermined threshold. In response to changes detected in the test environment, such as changes in ambient temperature and / or ambient pressure, You can also request it.

[0030] A gate system for initially determining the characteristics of the measurement system 100 by applying various measurement conditions. Another gate system is used to measure the controlled response and subsequently determine the characteristics of the measurement system 100. The controlled response can be measured. The measurement conditions include, for example, the frequency span (for example, the maximum (Also using a wider frequency span) and IF bandwidth (for example, using a lower IF bandwidth) The measurement system 100 is set to perform specific tests, such as reducing noise effects. This is a condition: The measurement conditions of DUT160 comply with the requirements for time-domain gating. The measurement conditions were matched to those used for measuring the S-parameters of the DUT160. This can be done. In this case, time-domain gating is a wind in the time domain. Using windowing, gates are generated at frequencies close to the start and end frequencies. Since the measurement results of the controlled response are distorted, the widest possible frequency range of the measuring instrument 110 is used. It is more preferable to use a pan to measure the S-parameters of the DUT160.

[0031] As another example, the measurement conditions are in the measurement channel used to perform S-parameter measurements. There is no other channel (correction channel) of the measuring instrument 110 that determines the characteristics of the measurement system 100. Applies to each channel (setup conditions, start / stop point, IF bandwidth). (Meaning) It takes time to set up, so reset the channel attributes. Rather, the measurement channel (for example, a center frequency of 1 GHz and a frequency spar of 100 MHz) (having a n) and a separate correction channel (for example, a starting frequency of 10 MHz, 26 GHz) Set up the stop frequency and the step size of 10 MHz, and these steps Switching between channels is faster. For example, measuring the S-parameters of DUT160 A wider frequency range than the measurement conditions used is set for the correction channel of the measuring instrument 110. It can be set. In relation to this, the correction channel is the initial in the software sense. Different types of points, such as the number of points or frequency span, can be used to store settings. It is a separate instance of a measurement software object that possesses certain properties.

[0032] The measurement system 100 then determines the effect of the changes on the S-parameter measurement of the DUT160. The desired change in properties is compensated for by removing the unwanted element. This can be done in various ways. This is possible. For example, compensating for a desired change in a characteristic can be done by using the desired change. Modify the error term of the initial calibration of the measurement system 100, and use the modified error term This may include correcting the measured values ​​of at least one S-parameter of the DUT160. It is possible. Another example of compensating for the requested change is to make the requested change at least one S parameter To remove from the data measurement, or to remove the desired change from at least one S-pack of the DUT This includes simply subtracting from the meter measurement. Furthermore, the calculated change is... Adjust the reference plane of the changes to obtain at least one measured S-parameter of DUT160. To match it and to compensate for the required change using the adjusted reference plane. Therefore, compensation is possible. The required change is the amplitude response of the delay offset (magnitud It is required as the response of a delay offset. The adjustment of the reference plane is done by DUT reflection track The ratio of the response (amplitude and phase) of King's (reflection tracking) can be obtained. Figure 1 This shows one port connected to DUT160 (the first port 101), but the measurement The other ports of the control device 110 are similarly connected to the other ports of the DUT 160, and the measurement system 1 00 can similarly compensate for the desired changes in the characteristics of these other connections. It is understood that this is possible.

[0033] Figure 2 shows how to measure at least one S-parameter of the DUT according to a typical embodiment. This is a simplified flowchart illustrating how to eliminate the effects of system instability used for [the purpose]. The process shown in Figure 2 is activated by the system, such as the processing unit 150 described above. This can be carried out at least partially by a processing unit capable of performing the task. That is, The memory (156) of the processing unit is controlled by the processor device (155) of the processing unit. When executed, it stores instructions that cause the processing device to perform the steps described below. It is configured in this way.

[0034] Referring to Figure 2, in block S211, the characteristics of the measurement system are first determined. The measurement system may be, for example, a VNA, network analyzer, or system analyzer. A measuring instrument capable of measuring at least one S-parameter of the DUT, and a few The system includes a connection circuit that connects the measuring instrument to the DUT, including a test cable. Determining its characteristics first is crucial for determining the temporal position of the instability of the measurement system in the time domain. Identifying and covering the identified locations of instabilities using time-domain gating Setting a gate time span and gate-controlled time in the frequency domain The gate-controlled response of the system over a span (e.g., return loss response or VS) This may include measuring the WR response. However, this was the first characteristic required of the measurement system, and this is what the measurement system remembers. It is possible.

[0035] In block S212, a change in the characteristics of the measurement system occurs when the measurement system comes into contact with the DUT. This is determined while the connection is being maintained. This change in characteristics is determined while the connection remains active. In several domains, over the same gate-controlled time span as block S211, the measurement system This is determined by measuring another gate-controlled response of the stem. The gate-controlled response is a characteristic of the measurement system obtained afterward, and is similarly stored. This can be done. Next, this change in properties is obtained by first determining the properties obtained afterwards. This is determined by comparing it with the characteristics. This change in characteristics is obtained by measuring the DUT from the measurement system. Without the need to disconnect, without the need to reconnect the calibration reference to the measurement system, and without the need to reconnect the connection cycle It can be requested without needing to include another device in the route.

[0036] In block S213, the desired change in the characteristics of the measurement system occurs when the measurement system Compensation is provided while connected to the DUT. This compensation applies to at least one of the DUTs. It is performed by removing the influence of the required changes on the measurement of the S parameter. Then the measurements made after the changes caused by instability are substantially the same as the measurements made prior to these changes, thereby compensating for changes in the test environment.

[0037] For example, from the change in the gate-controlled frequency domain response compensated by dividing by the reflection tracking term, a new compensated directivity term for DUT calibration can be found. Next, this result is subtracted from the directivity error term for DUT calibration according to Equation (1).

Equation

[0038] In Equation (1), EDF New is the compensated directivity for DUT calibration, E DF DUT is the DUT calibration directivity error term before compensation, ERF DUT is the DUT calibration reflection tracking term before compensation, and ΔS is the change in the gate-controlled S under the conditions of that calibration, assuming either an initial calibration or a factory calibration offset was used. 11_Gated 11

[0039] Figure 3A is a graph showing the return loss response of a DUT without removing the influence of measurement system instability, and Figure 3B is a graph showing the return loss response of a DUT with removing the influence of measurement system instability according to a representative embodiment.

[0040] Referring to Figure 3A, trace 311 causes instability in the measurement system ​​​​​​​​​​DUT(160) is measured by the measurement system (100) before any changes occur in the test environment. ) return loss (S 11 This is an initial signal indicating ). Therefore, this initial signal is unstable. It is not affected by gender. Trace 312, for example, in the measurement system, DUT liters measured by the measurement system after temperature changes in the test environment caused This is a subsequent signal indicating loss. As shown in the figure, the measured signal is trace 312a These instabilities are affected by undesirable fluctuations in [location].

[0041] Referring to Figure 3B, trace 321 causes instability in the measurement system. DUT(160) is measured by the measurement system (100) before any changes occur in the test environment. ) return loss (S 11 This is the initial signal indicating ). Trace 322 is used in the measurement system. The measurement system measures the temperature changes in the test environment that cause instability. This is a subsequent signal indicating the return loss of the DUT. However, the measurement system is disclosed. The effects of instability are eliminated according to the embodiment described, and as a result, trace 322 is obtained. This trace is substantially identical to the initial signal shown by trace 321. In other words, this subsequent signal is indicated by the absence of variation in trace 322. Therefore, it is not affected by the instability of the measurement system.

[0042] The present invention has been illustrated and described in detail in the drawings and the above description, but such explanatory drawings and The explanations should be considered illustrative or exemplary, not limiting, and this publication The documentation is not limited to the disclosed embodiments.

[0043] Aspects of the present invention can be embodied as an apparatus, method, or computer program product. Yes, it is possible. Therefore, in the embodiments of the present invention, the entire is a hardware embodiment, and the entire is a software embodiment. Embodiments of the software (including firmware, resident software, microcode, etc.), It can take the form of an embodiment that combines software and hardware aspects. These are all collectively referred to as “circuits,” “modules,” or “systems” in this specification. This may occur. Furthermore, in aspects of the present invention, computer executable code is embodied. It takes the form of a computer program product that is embodied in one or more computer-readable media. It is possible.

[0044] While typical embodiments are disclosed herein, those skilled in the art will be able to apply many of these teachings. It can be seen that various deformation forms are possible and fall within the scope of the attached patent claims. Therefore, the present invention is not limited to being within the scope of the attached claims. do not have.

Claims

1. A measurement system for measuring the S-parameters of a device under test (DUT), It has at least one port, and measures from the DUT through that at least one port A measuring machine configured to receive a constant signal and measure the S-parameters of the DUT. The vessel and The DUT is configured to be connected to at least one port of the measuring instrument. Connection circuit, A processing unit comprising a processor device and a memory for storing instructions, the When the instruction is executed by the processor device, it first determines the characteristics of the measurement system. The request and the request while the DUT is connected to the at least one port. To determine the change in the characteristics, and to determine the S-parameter of the DUT in relation to the measurement. By eliminating the effects of the changes, the DUT can be connected to at least one port. Compensating for the determined change in the aforementioned characteristics while connected and the processor The processing unit and A measurement system equipped with the following features.

2. To identify the location of the instability in the time domain of the aforementioned measurement system, Setting a gating time span that covers the identified location of the instability. 、 In the frequency domain, over the gating time span, the gate of the measurement system Measuring the controlled response as the initially desired characteristic and The processor device first determines the characteristics, according to claim 1. The measurement system described.

3. While the DUT is connected to the at least one port, in the frequency domain And over the aforementioned gating time span, another gate-controlled response of the measurement system Measuring the answer as a characteristic obtained afterward, By comparing the characteristics obtained thereafter with the characteristics obtained initially, Calculating the aforementioned changes in the characteristics and The processor device determines the change in the characteristic as described in claim 2. Measurement system.

4. Using the aforementioned changes in the initially determined characteristics, the initial measurement system Changing the error term in the calibration, The measured values ​​of the S-parameters of the DUT are corrected using the modified error term. Toto The processor device corrects the determined change as described in claim 1. Fixed system.

5. The change in the initially determined characteristic of the measurement system is determined by the DUT. To remove the S-parameters from the measured values. The processor device compensates for the determined change as described in claim 1. A measurement system.

6. The change in the initially determined characteristic of the measurement system is determined by the DUT. Subtract from the measured value of the aforementioned S-parameter. The processor device compensates for the determined change as described in claim 1. A measurement system.

7. The reference plane of the obtained change is adjusted, and the measured S-parameter of the DUT is To make them match, Compensating for the determined change using the adjusted reference surface, The required changes are determined as amplitude response and delay offset. The processor device compensates for the determined change as described in claim 1. A measurement system.

8. The processor device uses the initial calibration of the measurement system to detect the instability before the instability occurs. A measurement system according to claim 2, which identifies the marking position.

9. The processor device identifying the instability in the time domain is a calibration This includes using the time-domain response of unmeasured measurements to determine the location of the instability. The measurement system according to claim 2.

10. The device under test (D) connected to the Vector Network Analyzer (VNA) system. Influence of the instability of the VNA system on measuring at least one S-parameter of UT) A method for removing, First, determine the characteristics of the VNA system, To determine the change in the characteristics of the VNA system while it is connected to the DUT. 、 The obtained change in the measurement of at least one S-parameter of the DUT By eliminating the influence, the VNA system is connected to the DUT. To compensate for the aforementioned changes in the characteristics and Methods that include...

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