Accessory Devices

Abstract

The accessory device has a test port, an instrument port connected to a measuring instrument having an operating bandwidth, and one or more configurable signal paths connectable between the test port and the instrument port for converting signals from the test port having a first frequency range to signals having a second frequency range different from the first frequency range. The test and measurement system includes a test and measurement instrument having an operating bandwidth and an accessory device. The accessory device has a first instrument port for connecting the accessory device to the test and measurement instrument, a test port for connecting the accessory device to a device under test, and one or more configurable signal paths connectable between the test port and the instrument port for downconverting signals from the test port having the first frequency range to signals having a second frequency range lower than the first frequency range.

Description

[Technical Field]

[0001] This application is a continuation-in-part of and claims priority to U.S. Provisional Application No. 62 / 936,339, filed November 15, 2019.

[0002] The present disclosure relates to a test and measurement device Accessory devices used with Test and measurement equipment, especially in a wideband environment Accessory devices used with Regarding. [Background technology]

[0003] Wireless communication standards are rapidly advancing in terms of instantaneous bandwidth, allowing for faster and faster data transfer rates. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2009 / 0002213 [Patent Document 2] US Patent Application Publication No. 2012 / 0020397 [Patent Document 3] US Patent Application Publication No. 2011 / 0002472 [Non-patent literature]

[0005] [Non-Patent Document 1] "Arbitrary waveform generator" introduction site, especially introducing the AWG series, Tektronix, [online], [Retrieved July 15, 2022], Internet<https: / / jp.tek.com / arbitrary-waveform-generator> Summary of the Invention [Problem to be solved by the invention]

[0006] With each rollout of new standards, such as 3G, 4G, and 5G, bandwidth and data rates increase dramatically, making it difficult for traditional test equipment to keep up. One testing approach is to use real-time oscilloscopes and software to provide very wideband spectrum analysis, but the cost of this solution is high because the oscilloscopes provide bandwidths from DC to the upper end of the RF band being analyzed, with very high sample rates.

[0007] Another solution is to use a spectrum analyzer, but spectrum analyzers typically have a tunable center frequency, a relatively narrow operating bandwidth, a low sample rate, and are expensive.

[0008] SUMMARY OF THE INVENTION Embodiments of the disclosed apparatus and methods address shortcomings in the prior art. [Brief explanation of the drawings]

[0009] [Figure 1] Figure 1 shows a system diagram of test and measurement equipment and accessories. [Figure 2] Figure 2 shows a graphical representation of frequency and bandwidth. [Figure 3] Figure 3 shows a circuit diagram of a signal down converter for test and measurement equipment. [Figure 4] Figure 4 shows a circuit diagram of a combined signal down-converter and signal up-converter for a test and measurement instrument. [Figure 5] Figure 5 shows a block diagram of the DC bias tee source and load. [Figure 6] FIG. 6 illustrates an embodiment of a diplexer that can be used with an accessor for test and measurement equipment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Test and measurement equipment such as oscilloscopes and spectrum analyzers are struggling to keep up with the increasing bandwidth of wireless communications while keeping costs down. Using real-time oscilloscopes and software to provide wideband spectrum analysis covers bandwidths from DC to the upper end of the RF spectrum, which can be costly.

[0011] Another solution is to use a high-precision, low-speed oscilloscope in combination with a down-converter in front of it to expand the frequency range. Down-converter / oscilloscope systems, available in single-channel or multi-channel configurations, offer the cost-performance advantages of high precision, low cost, and the ability to expand performance in the future.

[0012] The present embodiment provides a cost-effective approach by using a block downconverter in front of a slow, low-bandwidth real-time oscilloscope or other test and measurement device (also referred to herein as an instrument). This instrument only needs to be fast enough to capture the desired RF bandwidth plus some margin for filter skirts. The trade-off for low cost is the complexity of building, controlling, and calibrating the combined downconverter and oscilloscope system. Conventional solutions, such as spectrum analyzers, tend to have a single channel with a digitizer that has a sample rate 10 to 100 times slower than the proposed solution.

[0013] FIG. 1 shows a block diagram of a test and measurement system 10 connected to a device under test (DUT) 12. An accessory device 14 is located between the DUT 12 and a measurement instrument 16. The accessory device 14 includes at least one downconverter 18 that receives signals from the DUT across the RF spectrum and then downconverts them to a lower frequency band for analysis by the measurement instrument 16. The test and measurement instrument 16 may be an oscilloscope, including a digital oscilloscope, and will generally have a higher operating bandwidth than other measurement instruments, particularly spectrum analyzers. For example, the test and measurement instrument 16 may have an operating bandwidth of at least 2, 3, 4, 5, 6, 7, or 8 GHz. In some embodiments, the test and measurement instrument 16 may be a wideband digitizer.

[0014] Accessory device 14 may include at least one additional down-converter (e.g., 20) that provides its output to a different channel on instrument 16 or that provides its output to a different instrument. Accessory device 14 may also include an up-converter 22 that receives a signal from a device, such as a waveform generator on the instrument or an external device, and provides an up-converted signal to DUT 12 via an output port. Those skilled in the art will appreciate that in alternative embodiments, accessory device 14 may include one or more up-converting signal paths, instead of down-converting signal paths 18, 20, to selectively up-convert signals from DUT 12 and provide the up-converted signals to instrument 16.

[0015] The accessory device 14 may connect to several other accessory devices (e.g., 25 and 27). The connection 28 between the accessory device 14 and the instrument 16 may include one or more cables over which multiple signals can travel. If the connection is a cable, the accessory device 14 may reside at the input end of the cable to minimize cable loss. Alternatively, the accessory device 14 may connect to the instrument 16 by attaching directly to the instrument. Many instruments employ standard input connectors, such as BNC or N-type connectors, for each input channel of the instrument. The accessory device 14 may be configured to connect to one or more of these standard connectors. Many instruments also employ custom electromechanical input connectors, such as the Tektronix FlexChannel® probe interface. The accessory device 14 may be configured to connect to one or more of these custom connector types. In some embodiments, the accessory device may be housed in a test measurement probe, such as in a probe head, and connected to the instrument by a probe cable. The accessory device 14 may also receive power from the instrument 16.

[0016] The instrument 16 typically includes at least one processor 24, at least one memory 26, and a user interface (U / I) 29. The processor may also include a programmatic interface. In some embodiments, a number of user-selectable switches may receive commands from the instrument, along with other settings such as down-converter frequency, as shown in FIG. 3. ofA user may select frequency ranges, switch settings, and other operating parameters through the user interface, and may provide control commands to the accessory device 14 through the control interface. As described in more detail below, the meter may control the operation of the accessory device to achieve specific performance parameters for the meter components, or may specify performance parameters for the combination of the accessory device and the meter as a system. The accessory device may send calibration information to the meter so that the meter can adjust for any errors introduced by the accessory.

[0017] 2 illustrates the bandwidth and frequency ranges of accessory device 14 and instrument 16 operating together. The instrument has a wide operating bandwidth, such as from 500 MHz to 8 GHz. A user can select one of multiple configurable signal paths within the accessory device to select a first frequency. range In Figure 2, the first frequency selected can be selected. range The center of the signal is shown as "BW", which is within a first frequency range and has a bandwidth of the first frequency BW. Typically, the first frequency BW and the second frequency BW are the same. By selecting one of multiple configurable signal paths within the accessory device, the user can convert the first frequency range to a second frequency range, where the second frequency range is within the wide operating bandwidth of the instrument 16. The user can use the accessory device to convert the second frequency to optimize performance within the second frequency range. range can be centered, where parameters that may be optimized include EVM, distortion, image suppression, and spurious signals.

[0018] 3 illustrates an embodiment of an accessory device having multiple configurable signal paths including down-converters (e.g., 18, 20 in FIG. 1). The circuit elements and frequency specifications used herein are provided for illustrative purposes only and are not intended to limit the scope of the embodiments to such specifics. Accessory device 14 may include a down-converter module 30 having multiple configurable down-conversion signal paths and an interface module 32 for delivering power frequency reference signals to a meter.

[0019] An embodiment of down converter 30 may have three paths between the input from device under test 12 and the output to instrument 16. Accessory 14 may have multiple input ports, including a test port 35 that receives an input signal from the DUT and a reference port 36 that receives an input signal from a calibration or reference signal source to enable calibration of the accessory module. Switch S6 selects between the two input terminals. Attenuator 34 may be comprised of a variety of controllable attenuators, including a voltage-controlled attenuator, a current-controlled attenuator, or a digital step attenuator.

[0020] When switch S6 is configured to receive the input signal from the DUT, the settings of the other switches determine which path the input signal takes to undergo downconversion. As shown, at least two paths perform downconversion, with an additional path, shown from switch S4 to switch S5, providing a bypass. The upper path, beginning with tunable filter 38, processes signals from 37 to 50 GHz in this embodiment. The tunable filter used here may consist of any of a variety of tunable filters, including voltage-controlled tunable filters, current-controlled tunable filters, and digital step filters. From filter 38, the signal passes to a buffer or low-noise amplifier (LNA) 40 and then to a frequency mixer 42. In embodiments where the buffer is an LNA, it may be fixed in the signal path, switchable in and out of the signal path, or an LNA with adjustable gain. The frequency mixer receives the filtered signal and a local oscillator signal, FLO1. The mixer creates an output signal having a particular frequency range, which is then low-pass or band-pass filtered at 44.

[0021] Switches S1 and S3 are synchronously selected, so that when S1 selects the upper path in the diagram, S3 feeds the output signal of the upper path to high-pass filter 46 and buffer 48. Filter 50 selects which frequency band reaches its output terminal. DC filter 52 provides a DC output. This allows signals between accessory devices and instruments to be transmitted all over a single cable. Extra output ports 56 and 58 allow instruments other than those shown in Figure 1 to receive the down-converted signal. The 10 MHz reference signal, passing through buffer 60 and band-pass filter 64, the DC signal, passing through low-pass filter 62, and the down-converted signal, passing through high-pass filter 66, all pass through the same cable.

[0022] These filters on the power / frequency / signal distribution circuitry block all DC bias and frequency reference signals supplied from the signal distribution module to the downconverters, while allowing the converted signals from the downconverters to pass through the signal distribution module to the instrument. This allows multiple signals to be combined on a single cable, reducing weight and cost while providing a simpler cable interface for downconverter / instrument users. Without this filtering, the 10 MHz reference signal would be distributed to each downconverter by coaxial cable, and each downconverter would have an independent power cable and a separate output coaxial cable.

[0023] The 10 MHz reference signal is also provided to bandpass filter 54, which passes the reference signal through buffer 68 to PLL 72. Local oscillator 70 is controlled by PLL 72, and local oscillator 74 is controlled by PLL 76. The output signals from these oscillators pass through frequency multipliers 78 and 80, which provide input signals FLO1 and FLO2 to mixers 42 and 82, respectively. Frequency multipliers 78 and 80 multiply the input frequency to provide an output frequency f out =f input *N (or M) and provide amplification and filtering functions to select the desired output frequency and output power level required by the mixer. The frequency multiplier may be configured as odd harmonic generators x1, x3, x5, x7 etc., even harmonic generators x2, x4, x6, combination generators x1, x2, x3, x4... xN etc.

[0024] Returning to the left side of the diagram, mixer 82 mixes the input signal from the center signal path if switches S1 and S4 are set to provide the input signal along this path. The input signal passes through variable filter 84 and buffer 86 and is mixed with signal FLO2 in mixer 82. It then undergoes low-pass or band-pass filtering in filter 88 and then proceeds to the output path similar to the upper signal path described above, with switch S3 set to select the center path.

[0025] The switch settings, PLL controls, variable filters, variable attenuators and other controllable components used will receive their setting and control instructions from the controller 90 through control interface signals from the instrument 16. The control interface may consist of a standard interface such as micro USB.

[0026] 1, accessory device 14 may include one or more down-converters 18, 20. Accessory device 14 may also optionally include an up-converter that can receive input signals from a local oscillator and waveform generator on or external to instrument 16 and provide a high frequency signal to the DUT. Figure 4 shows one embodiment of a combined down-converter / up-converter accessory device.

[0027] The downconverter circuit at the top of the figure is similar to the circuit of FIG. 3, but adds an upconverter. In the upconverter, the output signal of oscillator 70 passes through bandpass filter 100 and enters PLL 102. In either this circuit or the downconverter of FIG. 3, the output signal of PLL 76 of the downconverter may be coupled to an output line via local oscillator 74 to provide local oscillator output signal 92. Similarly, the output signal of PLL 102 may be coupled to an output line via local oscillator 103 to provide second local oscillator output signal 104. As noted above, accessory devices may control the instrument. The local oscillator may be adjustable. Adjusting the oscillator may adjust the performance of the test and measurement instrument, such as the performance parameters of one or more analog-to-digital converters in the test and measurement instrument. The oscillator may also generate a specific output signal.

[0028] The output signal of PLL 102 passes through one of two up-conversion paths, depending on the position of switch S11. As shown, this output signal passes through multiplier 109 to mixer 106, where it is mixed with an input signal from arbitrary waveform generator (AWG) 116 via S14 to produce a higher frequency signal. The mixer output is buffered by buffer 108, filtered by tunable filter 110, and attenuated by attenuator 112 to provide a 24-37 GHz output signal at second test port output terminal 113.

[0029] Alternatively, when switch S11 is in its other state, the output signal of PLL 102 passes through multiplier 107 and then into mixer 114. AWG 116 provides another input signal to mixer 114. AWG 116 has a bypass path defined by switches S14, S13, S12, and S10 as shown. but Furthermore GivenThe signal from AWG 116 passes through variable filter 118 and low-pass filter 120 before reaching mixer 114. Buffer 122 buffers the mixer's output signal, which is then filtered by variable filter 124. Variable attenuator 112 then attenuates the signal and provides it to output terminal 113 depending on the state of switch S8.

[0030] The up-converter may have a separate controller interface with controller 130 that receives control information 132. The controller may also receive a reference supply voltage from a reference input depending on the state of switches S6, S7, and S9. Reference block 134 may include temperature monitoring circuitry 134 that allows the controller to adjust for performance drift based on temperature. In this manner, up-converter circuitry can be added to accessory device 14.

[0031] Another potential concern is signal management of the downconverter signal using the DC signal and reference signal. This may require a termination network, such as a bias tee. Figure 5 shows an overview of termination, and Figure 6 shows a more specific embodiment. Figure 5 shows the RF signal from the DUT 12 traveling to the RF load (in this case, the instrument 16). The region between these two forms the combined signal region. In this combined signal region, the band from DC (i.e., a 0 Hz signal) to a low frequency is reserved for the DC power signal. This low frequency is user-determinable but could be, for example, 100 kHz. The band from some low frequency (100 kHz in this example) to a high RF, such as 10 GHz, is reserved for the downconverted DUT's RF or IF signal. The RF or IF component travels from the DUT to the load, while the DC component travels from right to left.

[0032] Figure 6 shows one embodiment of a diplexer. The illustrated sections work together to ensure good impedance matching at all frequencies. Section 140 is on the DUT, 142 is in the DC block of the accessory device, and 144 is in the down-converter or up-converter. Capacitor C3 is connected to the RF signal source 14. 1 The inductor in series with the RF path prevents DC from distorting this portion of the circuit. DC is filtered out by inductor L1 or other low-pass network. The capacitor in series with RF and the inductor in series with DC form a high-pass filter in the RF path and a low-pass filter in the DC path. Capacitor C2 or other high-pass filter on the right prevents DC from passing to the instrument's signal input. DC does not flow into the down-converter or RF section of the instrument. DC bias flows into the DC section of the down-converter or up-converter.

[0033] Aspects of the disclosed technology may operate on specially created hardware, firmware, digital signal processors, or specially programmed general-purpose computers, including processors that operate according to programmed instructions. The terms "controller" or "processor" herein contemplate microprocessors, microcomputers, ASICs, and dedicated hardware controllers, among others. Aspects of the disclosed technology may be implemented as computer-usable data and computer-executable instructions, such as one or more program modules, executed by one or more computers (including a monitoring module) or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., which, when executed by a processor in a computer or other device, perform particular tasks or implement particular abstract data formats. Computer-executable instructions may be stored in computer-readable storage media, such as hard disks, optical disks, removable storage media, solid-state memory, RAM, etc. Those skilled in the art will appreciate that the functionality of the program modules may be combined or distributed as desired in various embodiments. Furthermore, such functionality may be embodied in whole or in part in firmware or hardware equivalents, such as integrated circuits, field programmable gate arrays (FPGAs), etc. Certain data structures may be used to more effectively implement one or more aspects of the disclosed technology, and such data structures are considered within the scope of the computer-executable instructions and computer-usable data described herein.

[0034] The disclosed aspects may, in some cases, be implemented in hardware, firmware, software, or any combination thereof. The disclosed aspects may also be implemented as instructions carried by or stored on one or more computer-readable media, which may be read and executed by one or more processors. Such instructions may be referred to as a computer program product. As used herein, computer-readable media refers to any medium that can be accessed by a computing device. By way of example, and not limitation, computer-readable media may include computer storage media and communication media.

[0035] "Computer storage media" means any medium that can be used to store computer-readable information. By way of example and not limitation, computer storage media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory and other memory technologies, compact disc read-only memory (CD-ROM), DVD and other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage and other magnetic storage devices, and any other volatile or nonvolatile, removable or non-removable medium implemented in any technology. "Computer storage media" excludes signals themselves and transitory forms of signal transmission.

[0036] A communication medium means any medium usable for communicating computer-readable information. By way of example, and not limitation, communication media may include coaxial cable, fiber optic cable, air, or any other medium suitable for communicating electrical, optical, radio frequency (RF), infrared, acoustic, or other types of signals.

[0037] Additionally, the description of this application refers to specific features. It should be understood that the disclosure herein includes all possible combinations of these specific features. For example, if a specific feature is disclosed in connection with a particular embodiment, that feature can also be used in connection with other embodiments, to the extent possible.

[0038] Furthermore, when this application refers to a method having two or more defined steps or processes, these defined steps or processes may be performed in any order or simultaneously, unless the circumstances do not preclude this possibility.

[0039] Although specific embodiments of the invention have been illustrated and described for purposes of illustration, it will be appreciated that various modifications can be made therein without departing from the spirit and scope of the invention. Accordingly, the invention should not be limited except as by the appended claims. Example

[0040] The following examples are provided to aid in understanding the technology disclosed in this application. Embodiments of the technology may include one or more of the examples described below, and any combination thereof.

[0041] Example 1 is an accessory device comprising: a test port; an instrument port for connecting to an instrument having a specific operating bandwidth; and one or more configurable signal paths connectable between the test port and the instrument port, the signal paths converting a signal from the test port having a first frequency range into a signal having a second frequency range different from the first frequency range, the second frequency range being within the operating bandwidth of the instrument.

[0042] Example 2 is the accessory device of example 1, wherein the one or more configurable signal paths include one or more user-selectable switches for selecting the first frequency range.

[0043] A third embodiment is the accessory device of any one of the first and second embodiments, wherein the operating bandwidth of the measuring instrument is 5 GHz or greater.

[0044] Example 4 is the accessory device of any of Examples 1 to 3, wherein at least one frequency in the first frequency range is at least twice the operating bandwidth of a channel of the instrument.

[0045] Example 5 is the accessory device of any of Examples 1 to 4, wherein at least one of the one or more configurable signal paths includes a bypass path between the test port and the instrument port.

[0046] Example 6 is an accessory device of any of Examples 1 to 5, further comprising at least one auxiliary instrument port, and at least one of the one or more configurable signal paths is connectable between the test port and the auxiliary instrument port.

[0047] Example 7 is the accessory device of any one of Examples 1 to 6, further comprising a calibration input port and a calibration signal path connectable between the calibration input port and the measurement port.

[0048] Example 8 is the accessory device of any one of Examples 1 to 7, further comprising a control interface for receiving a control command.

[0049] Example 9 is an accessory device of any of Examples 1 to 8, wherein at least one of the one or more configurable signal paths includes a down converter that down converts a signal from the test port having a first frequency range to a signal having a second frequency range that is lower than the first frequency range.

[0050] Example 10 is an accessory device of any of Examples 1 to 9, further comprising an up-converter circuit connectable between the instrument port and the second test port, the up-converter circuit being connected to a waveform generator.

[0051] Example 11 is the accessory device of Example 10, wherein the up-converter circuit has a switch that, in a first state, supplies a waveform generator signal to the second test port, and, in a second state, supplies the waveform generator signal to a mixer together with a signal from the instrument port.

[0052] Example 12 is a test and measurement system comprising a test and measurement device having a specific operating bandwidth and an accessory device, the accessory device having a first instrument port for connecting the accessory device to the test and measurement device, a test port for connecting the accessory device to a device under test, and one or more configurable signal paths connectable between the test port and the instrument port, the one or more configurable signal paths having a down converter that down converts a signal from the test port having a first frequency range to a down converted signal having a second frequency range lower than the first frequency range, the second frequency range being within the operating bandwidth of the test and measurement device.

[0053] Example 13 is the test and measurement system of Example 12, wherein the accessory device includes at least one of a variable attenuator and a variable preamplifier controlled by the test and measurement instrument.

[0054] Example 14 is the same as Example 1 of 3 In a test and measurement system, the accessory device is either attached to the test and measurement instrument or is connected to the test and measurement instrument by a cable and the accessory device is connected to an input end of the cable.

[0055] Example 15 is the test and measurement system of any of Examples 12 to 14, wherein the accessory device is housed within the test and measurement probe.

[0056] Example 16 is a test and measurement system of any of Examples 12 to 15, wherein the accessory device further comprises a second down converter that transmits a second low-frequency signal to a second instrument port, the second low-frequency signal having a frequency that is lower than the first frequency and different from the frequency of the first low-frequency signal, and the second instrument port is connected to a different channel from the first instrument port of the test and measurement device.

[0057] Example 17 is the test and measurement system of any of Examples 12 to 16, wherein a user interface on the test and measurement device receives configuration for the accessory device.

[0058] Example 18 is the test and measurement system of any of Examples 12 to 19, wherein the accessory device receives power from the test and measurement device.

[0059] Example 19 is the test and measurement system of any of Examples 12 to 18, further comprising a local oscillator.

[0060] Example 20 is the test and measurement system of Example 19, wherein the local oscillator is adjustable.

[0061] Example 21 is the test and measurement system of Example 19, wherein the local oscillator is adjusted to adjust a performance parameter of an analog-to-digital converter in the test and measurement device.

[0062] Example 22 is the test and measurement system of Example 19, further comprising a local oscillator port configured to output a signal from the local oscillator.

[0063] Example 23 is the test and measurement system of any of Examples 12 to 22, further comprising a termination network for the device under test.

[0064] Example 24 is a test and measurement system of any of Examples 12 to 23, wherein the accessory device further comprises a power meter configured to measure the RF power of the signal from the test port and the RF power of the downconverted signal.

[0065] Example 25 is the test and measurement system of any of Examples 12 to 24, wherein the test and measurement instrument controls the accessory to achieve predetermined performance parameters for the test and measurement system.

[0066] Example 26 is the test and measurement system of any of Examples 12 to 25, wherein the accessory device is configured to transmit calibration information to the test and measurement instrument.

[0067] Example 27 is the test and measurement system of any of Examples 12 to 26, wherein the test and measurement device is either an oscilloscope or a wideband digitizer.

[0068] Although specific embodiments of the invention have been illustrated and described for purposes of illustration, it will be appreciated that various modifications can be made therein without departing from the spirit and scope of the invention. Accordingly, the invention should not be limited except as by the appended claims.

Claims

1. A test port for connecting to a device under test; an instrument port for connecting to an instrument having a particular operating bandwidth; one or more configurable signal paths connectable between the test port and the instrument port, the one or more configurable signal paths converting signals from the test port having a first frequency range to signals having a second frequency range different from the first frequency range; At least one auxiliary instrument port; Equipped with the second frequency range is within the operating bandwidth of the instrument; An accessory device, wherein at least one of the one or more configurable signal paths is connectable between the test port and the auxiliary instrument port.

2. A test port for connecting to a device under test; an instrument port for connecting to an instrument having a particular operating bandwidth; one or more configurable signal paths connectable between the test port and the instrument port, the one or more configurable signal paths converting signals from the test port having a first frequency range to signals having a second frequency range different from the first frequency range; a calibration input port; a calibration signal path connectable between the calibration input port and the measurement port; Equipped with An accessory device wherein the second frequency range is within the operating bandwidth of the instrument.

3. First and second test ports for connecting to a device under test; an instrument port for connecting to an instrument having a particular operating bandwidth; one or more configurable signal paths connectable between the first test port and the instrument port, the one or more configurable signal paths converting signals from the first test port having a first frequency range to signals having a second frequency range different from the first frequency range; an up-converter circuit connectable between the instrument port and the second test port and connected to a waveform generator; Equipped with the second frequency range is within the operating bandwidth of the instrument; The accessory device includes a switch in which the up-converter circuit provides a waveform generator signal to the second test port in a first state and provides the waveform generator signal along with the signal from the instrument port to a mixer in a second state.

4. 4. The accessory device of claim 3, wherein at least one of the one or more configurable signal paths includes a down converter that down converts a signal from the first test port having a first frequency range to a signal having a second frequency range that is lower than the first frequency range.

Images