Abstract: MIMO test systems and methods are provided that eliminate the need for a wired connection between the test system and the antenna ports of the DUT, thereby eliminating the need to open up the housing of the DUT and risk damaging or destroying it. The MIMO test systems and methods also eliminate the need for an anechoic chamber, thereby eliminating the cost and space requirements associated therewith. A suitable non-anechoic, electromagnetically-shielded chamber can be used in the test system that is much less expensive and that has a much smaller spatial footprint than a typical anechoic chamber used in MIMO test systems.

Abstract: Network analysis employs a band-limited multi-tone test signal having a tunable center frequency to test a device under test (DUT). A hybrid network analyzer includes a test signal source to provide the band-limited multi-tone test signal, and a local oscillator (LO) source to provide a tunable LO signal configured to track the tunable center frequency of the band-limited multi-tone test signal. The hybrid network analyzer further includes a receiver to convert into an intermediate frequency (IF) signal using the tunable LO signal one or both of the band-limited multi-tone test signal and a response signal from a device under test (DUT) produced in response to the band-limited multi-tone test signal. The test signal source is further configured to provide a tunable single-tone test signal and a broadband multi-tone test signal to test the DUT in various modes.

Abstract: A method for operating a data processing system having a touch enabled display screen that displays a plurality of waveforms to alter the display of one of the waveforms without altering the display of the remaining waveforms is disclosed. The method includes determining a selected waveform in response to a user touching the display screen in a first location thereby defining a touch area that determines the selected waveform. An operation that is to be performed on the selected waveform is then defined by a gesture on the screen. The selected waveform is determined by a touch area that is defined by the user touching the screen. If more than one waveform is defined by the touch area, the possible waveforms are sequentially selected until the correct one is presented to the user in response to the user repeating the touching that defines the touch area.

Abstract: A three-dimensional interconnect structure having a top surface, a first coaxial conductor, and a shielded chamber is disclosed. The first coaxial conductor is filled with a solid dielectric medium. The first coaxial conductor has a segment that runs parallel to the top surface and a segment connects the first coaxial conductor to the top surface. Conductive pads on the top surface are adapted to receive a signal and couple that signal to the first coaxial conductor at the top surface. The shielded chamber contains a device connecting two conductors that are part of the three-dimensional interconnect structure to one another in that chamber. The shielded chamber is filled with the solid dielectric medium. The structure is a solid block composed of a mixture of metal structures interspersed with the solid dielectric medium.

Abstract: The modular electronic instrumentation platform chassis is for use with a plurality of instrumentation modules and includes a frame defining a module area and a non-module area. The module area includes a plurality of slots open to a front of the frame and configured to receive instrumentation modules therein. A front panel may be carried by the front of the frame adjacent the plurality of slots. A chassis power unit is configured to provide power to the plurality of instrumentation modules received in the slots. A reference clock unit carried by the frame in the non-module area and is configured to provide a low phase-noise reference clock for the plurality of instrumentation modules received in the slots.

Abstract: A power sensor applies respective first and second currents having substantially equal magnitudes to a reference detector and a measurement detector that are thermally coupled to each other. The power sensor senses an input signal with the measurement detector, and it adjusts the respective magnitudes of the first and second currents by substantially equal amounts to correspondingly adjust a measurement characteristic of the measurement detector.

Abstract: A system and method sequentially measure the amplitude and phase of a signal in each of two or more noncontiguous spectrum segments (e.g., harmonics) which each include two or more portions which together span the spectrum segment, using a local oscillator (LO) signal whose frequency and phase change for each measurement. The measured phase of the signal for at least one of the portions in each spectrum segment is adjusted to account for the change of phase in the LO signal from measurement of one portion to another, using phases of one or more pilot tones measured in each portion. The phase-adjusted measurements of the output signal in the various portions are stitched together to determine the amplitude and phase of the output signal across the spectrum segment. The phase relationships between the spectrum segments are determined from phases of comb teeth of a comb signal measured in each spectrum segment.

Abstract: A test apparatus includes a vibratory body that shakes a device under testing (DUT), a pedestal dedicated to support the DUT and disposed on the vibratory body, and a clamping mechanism operative to selectively clamp the pedestal to the vibratory body and release the pedestal from the vibratory body. The vibratory body and the pedestal define a cavity in which the clamping mechanism is disposed. The clamping mechanism includes a clamp ring and at least one locking element carried by the clamp ring so as to be displaceable in a radial direction relative to the clamp ring, at least one tang facing the at least one locking element in the radial direction, and a piston slidable in an axial direction relative to the clamp ring between a first position at which the pedestal is free from vibratory body and a second position at which the locking element is compressed between the piston and the tang.

Abstract: A method for optimizing loop gain of an atomic force microscope (AFM) apparatus includes determining a change in gain of the physical system and adjusting a controller frequency response of the controller in an AFM loop to compensate for the determined change in gain. The AFM loop has a corresponding loop response that includes the product of the controller frequency response and a physical system response of the physical system.

Abstract: A current sensing circuit for sensing current in a DUT includes first and second input terminals; a shunt resistor connected to the first input terminal; a shunt resistor sensing circuit that amplifies voltage between terminals of the shunt resistor; a low pass filter coupled to an output of the shunt resistor sensing circuit; a current transformer having a primary winding connected between a terminal of the shunt resistor and the second input terminal; a current transformer sensing circuit connected to a secondary winding of the current transformer and configured to amplify current from the secondary winding; and an adder configured to add outputs of the low pass filter and the first current transformer sensing circuit. The current transformer sensing circuit includes a first transimpedance amplifier and a first input resistor. The current transformer has a low frequency-side cutoff frequency equal to a cutoff frequency of the low pass filter.

Abstract: Disclosed is a voltage-current characteristic generator that includes: a voltage source; a current source; a selector for selecting and outputting the output of either the voltage source or the current source; a sensing portion, connected to an output of the selector, for outputting the output of the selector and for sensing, and feeding back, the voltage and current of the output; and a controller for receiving the voltage and current detected by the sensing portion and for setting the subsequent outputs in the voltage source and the current source, wherein, in addition to setting the subsequent outputs, the controller evaluates an operating mode wherein the subsequent output from the selector is to be from either the voltage source or the current source.

Abstract: An atomic force microscope (AFM) comprises a physical system and a controller comprising a plurality of digital filters and configured to control the physical system. The AFM is tuned by performing automatic loop shaping on a loop response defined by a frequency response of the physical system and a frequency response of the controller, and adjusting a gain of the controller according to a peak in a magnitude of the loop response.

Abstract: A radio frequency (RF) measurement system acting as a spectrum analyzer and a method of operating the same eliminates image signals from a detected input RF spectrum. The method includes determining at least three local oscillator (LO) frequencies; determining LO offsets between the LO frequencies; and mixing the LO frequencies with the input RF spectrum to provide corresponding intermediate frequency (IF) signals having an IF bandwidth, where at least one of the IF signals has the input RF spectrum mixed to a different portion of the IF bandwidth than at least one other of the IF signals, providing overlapping coverage. The method further includes acquiring ADC time records for the IF signals; performing Fourier transforms (FTs) on the ADC time records to provide IF spectrums; and detecting RF responses from the IF spectrums to determine an RF response trace corresponding to the input RF spectrum.

Abstract: A high-voltage active measurement probe is for a measurement instrument such as an oscilloscope. The high voltage active measurement probe includes an input terminal configured to receive an input signal from a device under test (DUT), a first output terminal configured to transmit a first output signal to the measurement instrument for measurement and display of peak voltages, and a second output terminal configured to transmit a second output signal to the measurement instrument for high sensitivity measurement and display of low level voltages. A first probe signal path is between the input terminal and the first output terminal, and a second probe signal path between the input terminal and the second output terminal. A first amplifier is in the first probe signal path between the input terminal and the first output terminal, and a second amplifier is in the second probe signal path between the input terminal and the second output terminal.

Abstract: A measurement instrument and associated method: receive at a measurement instrument at least one victim signal from a device under test (DUT), the victim signal including crosstalk interference from one or more aggressor signals which are not received by the measurement instrument; extract from the victim signal an ideal data pattern for the received victim signal, where the ideal data pattern does not include intersymbol interference (ISI), a noise component, or crosstalk interference to the victim signal; ascertain from the received victim signal and the ideal data pattern the ISI for the victim signal; produce a difference signal as a difference between: (1) the received victim signal; and (2) a sum of the ideal data pattern and the ISI; and ascertain from the difference signal a sum of the noise component and the crosstalk interference from one or more aggressor signals which are not received by the measurement instrument.

Abstract: A system and method sequentially measure the amplitude and phase of an output signal of a device under test in each of two or more frequency ranges which together span the output signal spectrum, using a local oscillator (LO) signal whose frequency changes for each measurement. The measured phase of the output signal is adjusted for at least one of the frequency ranges to account for a change of phase in the LO signal from measurement of one frequency range to another frequency range, including applying to the measured phase a phase offset determined by measuring the phase of a pilot tone using the LO signal before and after the frequency of the LO signal changes from measurement of one frequency range to another. The phase-adjusted measurements of the output signal in the two or more frequency ranges are stitched together to determine the amplitude and phase of the output signal across the output signal spectrum.

Abstract: Optical synthesis of frequency-tracking signals employs square-law based frequency conversion of pairs of optical signals having a predetermined, relative frequency shift to provide output signals. An optically synthesized tracking signal source includes a square-law photodetector configured to provide a first output signal having a frequency equal to a frequency difference between a first optical signal pair. Another square-law photodetector is configured to provide a second output signal having a frequency equal to a frequency difference between a second optical signal pair that is a frequency-shifted version of the first pair. The signal source further includes an optical wavemeter configured to determine one or both of the first pair frequency difference and the second pair frequency difference. The first and second output signals are tracking signals having a frequency offset determined by a relative frequency shift between the first and second pairs of optical signals.

Abstract: A method is provided for compensating for impairment of an electrical signal output from a device under test (DUT), the impairment resulting from an impairment network. The method includes measuring an impaired electrical signal received at an electronic analyzer via the impairment network; applying a coded pulse sequence to the impairment network; estimating an impairment transfer function corresponding to the impairment based on the applied pulse sequence; and correcting the measured electrical signal using the impairment transfer function to determine the electrical signal output from the DUT.

Abstract: Systems and methods for determining a capacitance on a device-under-test (“DUT”). An example implementation includes a voltage signal generator that generates a voltage signal alternating between a high voltage and a low voltage at regular time intervals. The voltage signal generator causes a DUT current to flow in the DUT. The DUT current comprises a leakage current and a capacitance measurement current in response to the voltage signal. A current signal generator receives the DUT current from the DUT. The current signal generator generates a cancellation current signal alternating between high and low values at the regular time intervals of the voltage signal such that the cancellation current signal cancels the leakage current through the DUT. A signal measurement circuit receives the capacitance measurement current remaining after the leakage current is canceled to generate an output voltage having an output voltage value used to determine a capacitance of the DUT.

Abstract: An apparatus, a signal source, and a method for operating the same are disclosed. The apparatus includes a first signal source, a port, controller, signal synthesizer, and a first timestamp register. The port is adapted to receive a first clock signal that includes a sequence of pulses at a constant clock frequency. The signal synthesizer generates an output signal in response to inputs from the controller, the output signal having a first frequency. The first timestamp register counts pulses from the first clock signal. The controller is adapted to receive a command to change the output signal frequency from the first frequency to a second frequency, the controller causing the signal synthesizer to change the output signal frequency to the second frequency and to generate a frequency change timestamp from the timestamp register indicating a time at which the output signal changed from the first frequency to the second frequency.