Determining interference in communication channel

Abstract

The invention relates to determining interference in a communication channel. An exemplary system is configured to measure power based on a first signal in a first frequency band. The first signal includes an interference component of a second signal in a second frequency band adjacent to the first frequency band. The system includes a low pass filter (LPF) having a fixed frequency. The system includes a circuit configured to perform operations including: using a local oscillator to change a frequency to shift a center frequency of the first signal into an LPF; obtaining a measure of the power of the interfering component at a window in the first frequency band, wherein the attenuation of the LPF is at or above a predefined value; and determining a power of the interference component in the first frequency band based on the measurement in order to reduce an aliasing component in the first signal caused by the LPF.

Description

Technical Field

[0001] This specification describes exemplary implementations of techniques for identifying interference in communication channels. Background Technology

[0002] The test system is configured to test the operation of the equipment. The equipment tested by the test system is called the device under test (DUT). A DUT that transmits wireless signals (such as radio frequency (RF) signals) can be configured to transmit signals in a predefined communication channel or frequency band. The RF signals transmitted by the DUT in the communication channel may cause interference in one or more adjacent communication channels. Summary of the Invention

[0003] An exemplary method is used to measure power based on a first signal in a first frequency band. The first signal includes an interference component of a second signal in a second frequency band adjacent to the first frequency band. The first signal may be subjected to aliasing components from a low-pass filter (LPF). An exemplary implementation of the method uses a fixed LPF that has high attenuation in some portions of its stopband. By changing the down-conversion frequency using a local oscillator (LO), the same portions of the radio frequency (RF) signal will be attenuated differently by the LPF. A portion of the aliasing component will be attenuated by the high attenuation in the stopband. By combining multiple measurements at different frequencies, the contribution of the aliasing component to the first signal can be reduced, removed, or eliminated.

[0004] The method may include: using a low-frequency (LO) to change the frequency to shift the center frequency of the first signal into the low-frequency (LPF); obtaining a measurement of the power of the interfering component at a window in the first frequency band, wherein the attenuation of the LPF is at or above a predefined value; and determining the power of the interfering component in the first frequency band based on the measurement to reduce aliasing components in the first signal caused by the LPF. The method may include one or more of the following features (alone or in combination).

[0005] Obtaining this measurement when the attenuation of the LPF is at or above a predefined value removes all or some of the signal power of the aliasing component from the determined power of the interfering component. Obtaining this measurement may include the following operations: obtaining the bandwidth of a window; placing a digital baseband at the center of the first frequency band; placing the window based on an offset relative to the center of the digital baseband, wherein placing the window includes shifting frequencies within the first frequency band; measuring the power of the interfering component within the window; and repeating the placement and measurement operations for different values ​​of the offset to obtain the measurement. A vector signal analyzer (VSA) can be used to perform the measurement.

[0006] The offset Δf can be defined as follows:

[0007]

[0008] Where f is the center frequency of the digital baseband, and This refers to the frequency at which the LPF attenuation is at or above this predefined value. Setting this offset can include changing the frequency at each repetition. The value can be changed each time it is repeated. The value of is such that the window covers all frequencies in the first frequency band.

[0009] The bandwidth of this window can be set based on at least one of the target performance or the target test time. Determining this power may include summing the measurements.

[0010] The second signal in the second frequency band can be generated by the device under test (DUT). The method may include comparing the power of the interference component with a predefined threshold to test the DUT. This measurement can be performed by a vector signal analyzer (VSA) configured to measure a signal smaller than the sum of the first and second frequency bands.

[0011] This predefined value can be the minimum of multiple attenuation values ​​produced by the LPF. In the Z-plane of the LPF, this predefined value can be zero.

[0012] An exemplary system is configured to measure power based on a first signal in a first frequency band. The first signal includes an interfering component of a second signal in a second frequency band adjacent to the first frequency band. The system includes an LPF (Local Frequency Filter) having a fixed frequency response. The system includes circuitry configured to perform operations including: using a LO (Local Frequency Adapter) to change a frequency to shift the center frequency of the first signal into the LPF; obtaining a measurement of the power of the interfering component at a window in the first frequency band, wherein the attenuation of the LPF is at or above a predefined value; and determining the power of the interfering component in the first frequency band based on the measurement to reduce aliasing components in the first signal caused by the LPF. The system may include one or more of the following features (alone or in combination).

[0013] Obtaining this measurement when the attenuation of the LPF is at or above a predefined value removes all or some of the signal power of the aliasing component from the determined power of the interfering component. Obtaining this measurement may include the following operations: obtaining the bandwidth of the window; placing the digital baseband at the center of the first frequency band; placing the window based on an offset relative to the center of the digital baseband, wherein placing the window includes shifting the frequency in the first frequency band; measuring the power of the interfering component in the window; and repeating the placement and measurement for different values ​​of the offset to obtain the measurement.

[0014] At least a portion of the circuit may be located in the VSA. At least a portion of the circuit may include one or more processing devices and a memory storing instructions executable by the one or more processing devices. At least a portion of the circuit may include one or more solid-state electronic devices.

[0015] The offset Δf can be as follows:

[0016]

[0017] Where f is the center frequency of the digital baseband, and This refers to the frequency at which the LPF attenuation is at or above this predefined value. Setting this offset can include changing the frequency at each repetition. The value can be changed each time it is repeated. The value of is such that the window covers all frequencies in the first frequency band.

[0018] The bandwidth of this window can be set based on at least one of the target resolution or the target test time. Determining this power may include summing the measurements.

[0019] The second signal in the second frequency band can be generated by the DUT. The system may include test equipment configured to compare the power of the interference component with a predefined threshold to test the DUT.

[0020] This predefined value can be the minimum of multiple attenuation values ​​produced by the LPF. In the Z-plane of the LPF, this predefined value can be zero.

[0021] Any two or more of the features described in this specification (including the content section) may be combined to form specific embodiments not specifically described in this specification.

[0022] At least a portion of the devices, systems, circuits, and processes described in this specification can be configured or controlled by executing instructions stored on one or more non-transitory machine-readable storage media on one or more processing devices. Examples of non-transitory machine-readable storage media include read-only memory, optical disc drives, memory disk drives, and random access memory. At least a portion of the devices, systems, circuits, and processes described in this specification can be configured or controlled using a computing system comprising one or more processing devices and a memory storing instructions, which can be executed by the one or more processing devices to perform various control operations. The devices, systems, circuits, and processes described in this specification can be configured, for example, by design, construction, configuration, arrangement, placement, programming, operation, activation, deactivation, and / or control.

[0023] The accompanying drawings and the following detailed description illustrate one or more specific embodiments. Other features and advantages will become apparent from the details, the drawings, and the claims. Attached Figure Description

[0024] Figure 1 This is a block diagram of an exemplary test system component, including a control system and an exemplary vector signal analyzer.

[0025] Figure 2 This is a diagram illustrating an exemplary channel and an adjacent channel on which the device under test (DUT) transmits signals, and which contains interference and aliasing caused by measurements in the exemplary channel.

[0026] Figure 3 This is a diagram illustrating exemplary signal power measurements in adjacent channels caused by interference and aliasing from signals transmitted from the DUT.

[0027] Figure 4 This is a diagram illustrating an exemplary frequency response of an exemplary low-pass filter that can be part of a vector signal analyzer.

[0028] Figure 5 This is a diagram illustrating exemplary operations included in an exemplary process for determining interference in a channel, which remove, reduce, or minimize aliasing from the determined interference.

[0029] Figure 6 This is a diagram illustrating an exemplary channel, adjacent channels, and a sliding window. The DUT transmits a signal on the exemplary channel, the adjacent channel contains interference and aliasing, and the sliding window allows for the measurement of signal power or a measurement based on signal power.

[0030] Figure 7 It is shown Figure 6 A diagram of an exemplary channel, wherein the position of the sliding window in the channel is relative to... Figure 6 The positions within are different.

[0031] Figure 8 This is a drawing illustrating an exemplary determination of signal power obtained using existing technology and the systems and processes described herein.

[0032] Figure 9 This is another drawing illustrating an exemplary determination of signal power obtained using existing technology and the systems and processes described herein.

[0033] Similar reference numerals in different figures indicate similar elements. Detailed Implementation

[0034] This document describes examples of systems and processes for determining the power of interfering signals in a frequency band. Interfering signals, also known as interference components, are generated by device signals in adjacent frequency bands. That is, interfering signals are artifacts or components of device signals, and therefore can be referred to as interference components. Frequency bands define different communication channels (“channels”) through which signals can be transmitted between the device under test (DUT) and the test system. Therefore, the terms “frequency band” and “channel” are used interchangeably.

[0035] The DUT can be any type of electronic device, such as, but not limited to, a radio frequency (RF) transceiver configured to implement wireless communication functions such as cellular, WiFi, Bluetooth, or GPS (Global Positioning System) functions.

[0036] The systems and processes described herein can use a vector signal analyzer (VSA) to obtain measurements of the power of interference components in a channel or measurements based on the power of interference components in a channel. An exemplary VSA can be configured to measure the amplitude and phase of a signal at frequencies within the VSA's bandwidth.

[0037] Figure 1 Exemplary components that may be included in an exemplary VSA 10 are shown, which may be used to implement at least a portion of the systems and processes described herein. This component implements a direct downconversion receiver configured to demodulate RF signals using synchronization detection driven by a local oscillator (LO).

[0038] An exemplary VSA 10 includes: an antenna 11 that receives an RF signal from a channel; a band-selective filter 14 that selects a signal in a predefined channel or frequency band; a low-noise amplifier (LNA) 15 that amplifies the selected signal; a mixer 16 having a frequency driven by the frequency of the VSA LO; a low-pass filter (LPF) 17; an amplifier 19; and an analog-to-digital converter (ADC) 20. In some specific implementations, the measurements described herein can be performed without using an antenna. For example, a wired (e.g., coaxial) connection can be used instead of an antenna configured to receive RF signals.

[0039] When using a VSA to test a DUT, the VSA obtains out-of-band (or channel) power measurements to ensure that the DUT's interference to adjacent channels is limited to specifications. Such tests can include, for example, spectrum emission shielding tests, adjacent channel leakage tests, and occupied bandwidth tests.

[0040] As the bandwidth of the DUT signal increases, the required bandwidth of the VSA may need to increase. For cheaper test instruments with a VSA that can only cover one channel, an exemplary approach to measuring out-of-band signals generated by the DUT is to shift the VSARF center frequency to an adjacent channel and measure only the adjacent channel, for example, by placing the DUT signal outside the bandwidth of the VSA.

[0041] However, due to the limited performance of the LPF 17 in the VSA, a portion of the equipment covered by the LPF is converted to the VSA digital baseband as spurious signal power (referred to as aliasing or aliasing component) in the channel adjacent to the channel containing the DUT signal. Figure 2 This phenomenon is illustrated.

[0042] More specifically, Figure 2 Two adjacent channels (bands) 22 and 23 are shown. These two adjacent channels may have equal or substantially equal bandwidths (e.g., a difference of ±5% or ±10% in some examples). The DUT signal 11 is mostly located in channel 23. Interference signal / component 24 is located in channel 22. The interference signal / component may be caused, for example, by power leakage from the DUT signal 11 to channel 22.

[0043] The digital baseband center 26 of VSA 10 is marked as 0. Figure 2 In the example shown, [-f s / 2,f s [ / 2] is the available baseband range of LPF 17, where f s This is the center frequency of the DUT signal 11, as described below. The bandwidth 27 of the LPF 17 covers channel 22. However, as... Figure 2 As shown, LPF 17 is imperfect, and therefore its bandwidth 27 also covers a portion 30 of channel 23. This causes the power from DUT signal 11 to be reflected 31 back into channel 22 as aliasing component 32. In some specific implementations, aliasing assumes in-phase / quadrature sampling (I / Q) within the VSA. The aliasing component disrupts the measurement of interference component 24 in channel 22 obtained by VSA 10, or disrupts measurements based on that interference component. The systems and processes described herein are configured to determine the power of interference components in channel 22 in order to remove, reduce, and / or minimize the signal power of the aliasing component in the determined power of the interference components.

[0044] For example, refer to Figure 1 and Figure 2 According to sampling theory, for the received RF signal x(t) (such as the DUT signal) and LPF With a sampling rate f sAfter ADC 20, the characteristics of the digital signal IQ (in-phase, quadrature) sample y(n) are as follows:

[0045]

[0046] The baseband frequency domain signal Y(f) is defined as follows.

[0047]

[0048] The DUT signal 11X(f) in channel 23 is f s Centered on, and Centered at f=0, it has a cutoff frequency f s / 2.

[0049] Consider an example where the DUT signal 11 is centered on the right side of the VSA bandwidth, and assume that the LPF 17 has a 1 / 2 attenuation in an in-band region such as channel 23. This leads to the following simplified version of equation (2) above.

[0050]

[0051] The equation shows that the determined (e.g., measured) power of the interference component in channel 22 adjacent to channel 23, where the DUT signal 11 is transmitted, includes DUT-adjacent channel interference X(f)24 from DUT channel 23 and aliasing components.

[0052] Figure 3 It shows the VSA (e.g.) Figure 1 10) of the measures taken against adjacent channels (e.g.) Figure 2 The DUT signal in 22) (e.g.) Figure 2 Exemplary interfering components (e.g., in 11) Figure 2 The power spectral density (PSD) (in dBm / RBW) and frequency (in Hertz (Hz)) of 24) are measured. 36. In this example, this is achieved by combining / stitching together multiple VSA captures performed at different RF frequencies. Figure 3 In this example, the VSA is centered at 200 MHz to the left, 0 MHz to the center, and 200 MHz to the right of the DUT signal channel (e.g., 23). The exemplary VSA has a sampling rate of 240 MHz but a flatness of 200 MHz. This is why it's stitched at 200 MHz. The mathematics here describes the frequency range that the discrete signal (IQ sample) can be observed. Narrow bandwidth signals are used to make the effects more significant to be observed. In this example, the signal from the ADC (e.g., Figure 1The aliasing components 37 and 39 of the DUT signal at sampling rate (240MHz) are located in the left and right VSA captures. Aliasing components contribute to incorrect measurements of adjacent channel interference (e.g., leakage power) of the DUT.

[0053] In order to remove, reduce and / or minimize the aforementioned mixed components (which are denoted as...) The exemplary specific implementations of the systems and processes described herein use LPF (e.g., Figure 1 The attenuation and reduction (e.g., minimization) of the LPF frequency response in 17)

[0054] Figure 4 An exemplary frequency response 38 for an exemplary LPF 17 is shown. In this example, the "cutoff frequency" is used for the LPF, and the angular frequency ω is normalized to the "cutoff frequency" ωc, where ω / ωc is the x-axis. The cutoff frequency can be placed anywhere based on what will be optimized. Figure 4 In the example, there are three distinct filter responses, two of which have null values ​​in the stopband. The two 38b and 38c values ​​in the frequency response are shown as dashed lines. In some specific implementations, these two are not used in the process described herein.

[0055] like Figure 4 As shown, the frequency range of the discrete signal is [-f s / 2,f s / 2]41 (i.e., the Nyquist frequency), and the LPF filter has a frequency value of 40 at maximum attenuation. It can be defined as follows.

[0056]

[0057] It is the baseband frequency that causes the maximum attenuation of LPF.

[0058] For example, if in [f s -f s / 2,f s +f s If there exists any zero (s-plane) at the unit circle within [ / 2], then This will be the frequency of zero. Therefore, in order to reduce (e.g., minimize) the power P of the aliasing component with the bandwidth to be measured BW. alis For example, the "min P" below ails The LPF frequency response should be at...

[0059]

[0060] Equation (5) means that the frequency response of the LPF is fixed at a single frequency. The baseband frequency f changes within the measured bandwidth BW. However, this may not be possible. Equation (5) can be rewritten to make the baseband frequency f determine the LPF frequency response. Thus, the following equation is obtained.

[0061]

[0062] in

[0063]

[0064] Based on equation (7), for a baseband frequency f, Δf is defined as the VSA LO offset, or simply the LO offset. For any frequency f to be measured by the VSA, different LO offsets Δf can be added to adjust the center frequency of the signal entering the LPF. Shift to The value at which the reduction occurs or the minimum value is reached. Therefore, equations (6) and (7) together illustrate the characteristics of the system and process described herein; that is, the following will discuss the reduction or minimum value at which the reduction occurs. Figure 5 , Figure 6 and Figure 7 The frequency domain sliding window is described. The bandwidth (RBW) of this sliding window is a trade-off between performance and test time. For example, a narrower window bandwidth may result in more accurate power measurements, but a longer test time. Conversely, a wider window bandwidth may result in less accurate power measurements, but a shorter test time.

[0065] The adjacent channels (such as channel 22) with reduced or minimized aliasing components can be determined by summing measurements (e.g., power measurements) at each window k under BW. Figure 2 The measured power of the interfering component in )) is illustrated in equation (8) below.

[0066]

[0067] Where k is the index of the sliding window (k is an integer ≥ 1), Δf is the VSA LO offset of window k, and where

[0068]

[0069] The following description Figure 5 , Figure 6 and Figure 7 Examples of sliding window and summation operations using the mathematical interpretation of the aforementioned equations are provided.

[0070] More specifically, Figure 5This is a flowchart illustrating exemplary operations performed by an exemplary system and included in exemplary process 45, the flowchart being used to determine adjacent channels (such as...) Figure 2 The power of the interfering component in channel 22) is used to remove, reduce, and / or minimize the signal power of the aliasing component from the determined power of the interfering component. When describing the operation of process 45, refer to... Figure 1 , Figure 2 , Figure 6 and Figure 7 .

[0071] In this example, process 45 may use circuit-controlled... Figure 1 A test system for a VSA of the type shown is used to perform the test. This circuit may include one or more computing devices, such as those described herein. Such circuitry or computing devices may or may not be part of the test instrumentation or control system. Examples of this circuitry include... Figure 1 The control system 52, an example of which may be or include one or more processing devices, examples of which are described herein.

[0072] refer to Figure 1 An exemplary test system including a VSA also includes a control system 52. The control system 52 may be configured (e.g., programmed) to communicate 54 with the VSA 10 and / or one or more test instruments including the VSA 10 or instances thereof, thereby guiding and / or controlling the testing of the DUT in the manner described herein. In some implementations, this communication 54 may be via a computer network or via a direct connection (such as a computer bus or optical medium). In some implementations, the computer network may be or include a local area network (LAN) or a wide area network (WAN).

[0073] The control system 52 may be or includes a computing system comprising one or more processing devices 56 (e.g., microprocessors) and a memory 58 for storing machine-executable instructions 60, which can be executed by the processing devices to control the operation and / or testing of the test system including the VSA, to implement at least a portion of the process 45 described below. Process 45 will be described with respect to the VSA 10 and the control system 52; however, process 45 may be executed using different hardware and other hardware described herein.

[0074] Process 45 includes (34) characterizing LPF 17 and determining the reduced or minimum frequency response of LPF 17; for example, the baseband frequency that causes the maximum attenuation of LPF. This operation can be performed by control system 52, which can be programmed using the type and properties of LPF. In some specific implementations, LPF 17 is a fixed LPF with large attenuation (e.g., null or zero) in one or more portions of its stopband.

[0075] Characterizing the LPF can include identifying where the attenuation of the LPF 17 in the stopband is at or above a predefined value. In this respect, attenuation is a reduction in the frequency response of the LPF; therefore, an increase in attenuation means an increase in the reduction of the frequency response of the LPF. In some examples, the predefined value is or includes the minimum of several values ​​that constitute the attenuation of the LPF. In some examples, the predefined value is at or above 70 dB of attenuation relative to the LPF passband.

[0076] Process 45 includes obtaining the window bandwidth RBW of the sliding window 47 (45b). Figure 6 , Figure 7 This operation can be performed by control system 52, which can be programmed using the bandwidth of adjacent channel 22, target performance, and target test time. For example, this information can be programmed into control system 52 by a test engineer before execution process 45.

[0077] It can be or include the bandwidth of the window 49 ( Figure 6 , Figure 7 The bandwidth RBW of window 47 can be set in or by the control system 52 based on target performance, target test time, or both target performance and target test time. In some implementations, the bandwidth of window 47 does not change during process 45.

[0078] The target performance and target test time can be programmed into the control system 52. For example, this information can be programmed into the control system 52 by a test engineer before execution process 45. The target test time can include the amount of time available to test each individual DUT; that is, testing for interference caused by a signal output from a DUT in channel 22 adjacent to channel 23 that transmits the DUT signal. The target performance can include the desired accuracy or resolution of the test. In this regard, a smaller bandwidth (RBW) can produce a more accurate determination of interference in adjacent channel 22 or related to that interference. However, the smaller the window bandwidth, the more measurements must be taken, leading to an increase in test time.

[0079] Process 45 includes placing the digital baseband center frequency 50 (45c) in the adjacent channel 22 by changing the LO frequency of the VSA, such as Figure 6 , Figure 7As shown. Changing the LO frequency alters the center frequency of the signal entering the LPF. By changing the down-conversion frequency of the input signal to the LPF 17, the same portion of the RF signal will be attenuated differently by the LPF. A portion of the aliasing component will be significantly attenuated by the high attenuation in the stopband.

[0080] Placing the digital baseband center frequency may include allocating the digital baseband center frequency to adjacent channels 22. This may include identifying the bandwidth of adjacent channels 22, which is -f in this case. s / 2 to f s / 2, where f s As defined above, and including the identification of the center of adjacent channel 22 based on this bandwidth. The digital baseband center frequency can be assigned to the center of adjacent channels. For example, the bandwidth of adjacent channels can be programmed into the control system 52 by the test engineer, or determined by the control system 52 as an equivalent to the known bandwidth of channel 23 on which the DUT communicates.

[0081] Also refer to Figure 6 Process 45 includes placing (45d) window 47 based on LO offset Δf62 relative to the digital baseband center frequency 50, which corresponds to the center frequency 64 of LPF 17. In this respect, for window k47 (where k is an integer ≥1), the LO offset Δf... k Alternatively, it can be changed as follows: in It is the value of the LPF frequency response with attenuation at or above a predefined value, and where The digital baseband center frequency is 50 Hz. LO offset Δf k The LO offset can be changed based on the bandwidth of adjacent channels. For example, as described below, the LO offset can be increased or decreased to move the window across channels, so that the entire channel 22 or a portion of channel 22 is covered by the window to obtain measurements at different frequencies.

[0082] Process 45 includes obtaining (45e) a measurement of the power of the signal (e.g., interfering components) in channel 22 at window 47, or a measurement based on that power. This measurement can be a direct measurement of the power or a measurement of other properties of the signal (such as its amplitude). Measurements can be performed at any location within the window, or multiple measurements can be performed across the window and processed (e.g., averaged) to obtain the power measurement. In this example, the power is the power of the interfering components generated by the DUT signal in channel 22, where aliasing components have been removed, reduced, or minimized. VSA 10 can be controlled (e.g., instructed) by control system 52 to obtain the (45e) measurement.

[0083] The value of the LO offset Δf kAs described above, it is changed (45f). For example, control system 52 can change the value of LO offset Δf. k Operations (46) 45d to 45f are repeated for different values ​​of the LO offset to obtain measurements of signal power at different frequencies covered by window 47, or measurements based on that signal power. By changing the down-conversion frequency using different values ​​of the LO offset, the same portion of the RF signal will be attenuated differently by the LPF. A portion of the aliasing component will be significantly attenuated by the high attenuation in the stopband of the LPF.

[0084] For example, such as Figure 7 As shown, the VSA LO offset value Δf k 62 is changed to shift window 47 relative to the digital baseband center frequency 50, where one or more measurements can be obtained (45e). Thus, process 45 operates by shifting or displacing the center frequency of the signal entering the LPF using the VSA LO across the frequency in channel 22, and obtaining a measurement (45e) of the power of the interference component at different frequencies in channel 22 or a measurement based on that power, where the attenuation of LPF 17 is at or above a predefined value.

[0085] In some specific implementations, operations 45d to 45f can be repeated once or multiple times until the entire portion of channel 22 is measured, where the attenuation of the LPF is at or above a predefined value, for example, where the frequency response in the Z plane of the LPF is at or substantially zero.

[0086] Process 45 includes determining (45g) the power of the signal (in this example, the interference component) in channel 22 based on measurements. The power of the signal in channel 22 can be determined by summing the measurements, as explained above with respect to Equation 8. By combining (e.g., summing) multiple measurements at different frequencies, contributions from aliasing signals can be removed, reduced, or minimized.

[0087] Because the measurement is obtained at a position where the LPF attenuation is at or above a predefined value—for example, when the frequency response of the LPF is at or substantially zero in the Z-plane of the LPF—the aliasing component is sufficiently attenuated before being aliased, and therefore is not measured. Thus, in some cases, the effect is to remove the contribution of the aliasing component from the measurement of the interference component in channel 22 generated by the DUT signal. In other cases, the effect is to reduce or minimize the contribution of the aliasing component from the measurement of the interference component in channel 22 generated by the DUT signal.

[0088] Figure 8 It shows the use of and Figure 3The determination corresponds to an exemplary narrow-bandwidth signal spectrum determination 70 in the prior art, and an exemplary narrow-bandwidth signal spectrum determination 71 using the system and process described herein. As shown, determination 71 using the system and process described herein removes all or part of the aliasing components 72, 73 while fully or substantially preserving the initial signal spectrum characteristics. In some specific embodiments, the spikes 78 shown on the left are not removed by the process described herein.

[0089] Figure 9 An exemplary wideband signal spectrum determination 75 using prior art is illustrated, as well as an exemplary wideband signal spectrum determination 76 using the systems and processes described herein. As shown, determination 76 using the systems and processes described herein removes all or part of the aliasing components 77 while fully or substantially preserving the initial signal spectrum characteristics.

[0090] Return to reference Figure 5 To test the DUT transmitting signal 11 in channel 23, process 45 includes comparing (45g) the determined (45g) power value of the interfering component with a predefined threshold (45h). This operation can be performed by test equipment or other components of a test system configured to test the DUT. The predefined threshold can be programmed into the test system. If the power value of the interfering component is less than the predefined threshold, the DUT passes the test. If the power value of the interfering component is greater than or equal to the predefined threshold, the DUT may fail the test. The test system can report (45i) to the user whether the DUT has passed or failed the test at the user interface, etc., and / or can assign passed and failed DUTs to appropriate boxes.

[0091] The systems and processes described herein (including, but not limited to, process 45), in whole or in part, and variations thereof, may be configured and / or controlled at least in part by one or more computers using one or more computer programs tangibly embodied in one or more information carriers, such as one or more non-transitory machine-readable storage media. The computer programs may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as standalone programs or as modules, parts, subroutines, or other units suitable for a computing environment. The computer programs may be deployed to execute on a single computer, or on multiple computers distributed and interconnected at one location or across multiple locations.

[0092] Actions associated with configuring or controlling the test systems and methods described herein may be performed by one or more programmable processors that execute one or more computer programs to control or perform all or some of the operations described herein. All or part of the test systems and methods may be configured or controlled by dedicated logic circuit systems (such as FPGAs (Field-Programmable Gate Arrays) and / or ASICs (Application-Specific Integrated Circuits)) or embedded microprocessors localized to instrument hardware.

[0093] Processors suitable for executing computer programs include, for example, both general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Typically, a processor receives instructions and data from read-only memory or random access memory, or both. The components of a computer include one or more processors for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include one or more machine-readable storage media or be operatively coupled to one or more machine-readable storage media to receive data from or transfer data to, or both, such as mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks. Non-transitory machine-readable storage media suitable for embodying computer program instructions and data include all forms of non-volatile memory, including, by way of example, semiconductor memory devices such as EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), and flash memory devices; magnetic disks such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM (Optical Disc Read-Only Memory) and DVD-ROM (Digital Universal Optical Disc Read-Only Memory).

[0094] As used herein, the terms “comprises,” “comprising,” “including,” “has,” “having,” “contains,” “containing,” and any variations thereof are intended to cover non-exclusive inclusion, such that a system, technique, apparatus, structure, process, or other subject matter that includes, has, or contains elements or lists of elements described or claimed herein includes not only those elements, but may include other elements not expressly listed or other elements inherent to such systems, techniques, apparatus, structures, processes, or other subject matter described or claimed herein.

[0095] All examples described in this article are non-limiting.

[0096] In the specification and claims provided herein, the adjectives “first,” “second,” “third,” etc., do not specify priority or order unless the context otherwise requires. Rather, these adjectives are used only to distinguish the nouns they modify.

[0097] Unless the context otherwise requires, any mechanical or electrical connection herein can include a direct physical connection or an indirect physical connection including one or more intermediary devices. Unless the context otherwise requires, a connection between two conductive devices includes an electrical connection. Signals described herein are electrical signals unless the context otherwise requires.

[0098] The elements of the different embodiments described may be combined to form other embodiments not specifically described above. Elements may be omitted from the previously described system without generally adversely affecting its operation or the operation of the system. Furthermore, individual elements may be combined into one or more single elements to perform the functions described in this specification.

[0099] Other specific embodiments not specifically described in this specification are also within the scope of the following claims.

Claims

1. A method for measuring power based on a first signal in a first frequency band, the first signal including an interference component of a second signal in a second frequency band adjacent to the first frequency band, the method comprising: Use a local oscillator to change the frequency to shift the center frequency of the first signal into a low-pass filter (LPF); The power of the interference component at a window in the first frequency band is measured, wherein the attenuation of the LPF is at or above a predefined value; and The power of the interference component in the first frequency band is determined based on the measurement in order to reduce the aliasing component in the first signal caused by the LPF.

2. The method of claim 1, wherein obtaining the measurement when the attenuation of the LPF is at or above the predefined value removes the signal power of the aliasing component from the determined power of the interfering component.

3. The method of claim 1, wherein obtaining the measurement comprises: Obtain the bandwidth of the window; The digital baseband is placed at the center of the first frequency band; The window is positioned based on an offset relative to the center of the digital baseband, wherein positioning the window includes shifting frequencies in the first frequency band; Measure the power of the interfering component in the window; and The placement and measurement were repeated for different values ​​of the offset to obtain the measurement.

4. The method of claim 3, wherein a vector signal analyzer (VSA) is used to perform the measurement.

5. The method according to claim 2, wherein the offset Δf is defined as follows: Where f is the center frequency of the digital baseband, and It is the frequency at which the attenuation of the LPF is at or above the predefined value.

6. The method of claim 5, wherein setting the offset includes changing the offset at each repetition. value.

7. The method of claim 6, wherein the change is made during each repetition. The value of the value is such that the window covers all frequencies in the first frequency band.

8. The method of claim 3, wherein the bandwidth of the window may be set based on at least one of target performance or target test time.

9. The method of claim 1, wherein determining the power comprises summing the measurements.

10. The method of claim 1, wherein the second signal in the second frequency band is generated by the device under test (DUT); and The method further includes: The power of the interfering component is compared with a predefined threshold to test the DUT.

11. The method of claim 1, wherein the measurement is obtained by a vector signal analyzer (VSA) configured to measure a signal smaller than the sum of the first and second frequency bands.

12. The method of claim 1, wherein the predefined value is the minimum of a plurality of attenuation values ​​generated by the LPF.

13. The method of claim 1, wherein the predefined value is zero in the Z-plane of the LPF.

14. A system for measuring power based on a first signal in a first frequency band, the first signal including an interference component generated by a second signal in a second frequency band adjacent to the first frequency band, the system comprising: A low-pass filter (LPF) having a fixed frequency response; and A circuit configured to perform operations including: Use a local oscillator to change the frequency to shift the center frequency of the first signal into a low-pass filter (LPF); The power of the interference component at a window in the first frequency band is measured, wherein the attenuation of the LPF is at or above a predefined value; and The power of the interference component in the first frequency band is determined based on the measurement in order to reduce the aliasing component in the first signal caused by the LPF.

15. The system of claim 14, wherein obtaining the measurement when the attenuation of the LPF is at or above the predefined value removes the signal power of the aliasing component from the determined power of the interfering component.

16. The system of claim 14, wherein obtaining the measurement comprises: Obtain the bandwidth of the window; The digital baseband is placed at the center of the first frequency band; The window is positioned based on an offset relative to the center of the digital baseband, wherein positioning the window includes shifting frequencies in the first frequency band; Measure the power of the interfering component in the window; and The placement and measurement were repeated for different values ​​of the offset to obtain the measurement.

17. The system of claim 16, wherein at least a portion of the circuit is located in a vector signal analyzer (VSA).

18. The system of claim 16, wherein the offset Δf is defined as follows: Where f is the center frequency of the digital baseband, and It is the frequency at which the attenuation of the LPF is at or above the predefined value.

19. The system of claim 18, wherein setting the offset includes changing the offset at each repetition. value.

20. The system of claim 19, wherein the change is made during each repetition. The value of the value is such that the window covers all frequencies in the first frequency band.

21. The system of claim 16, wherein the bandwidth of the window can be set based on at least one of a target resolution or a target test time.

22. The system of claim 14, wherein determining the power comprises summing the measurements.

23. The system of claim 14, wherein the second signal in the second frequency band is generated by the device under test (DUT); and The system further includes a test setup configured to compare the power of the interference component with a predefined threshold to test the DUT.

24. The system of claim 14, wherein the predefined value is the minimum of a plurality of attenuation values ​​generated by the LPF.

25. The system of claim 14, wherein the predefined value is zero in the Z-plane of the LPF.

Images