Abstract: Responses of voltage and current probes are characterized or corrected. A voltage probe method includes measuring output of the voltage probe and a first output of a through, in response to an input signal applied to the through, with the voltage probe connected, measuring a second output of the through with the voltage probe disconnected, and characterizing the response of the voltage probe using the output of the voltage probe and the first and/or second outputs. A current probe method includes measuring output current of the current probe and first output current of a through, in response to an input signal applied to the through with the current probe connected in series, measuring second output current of the through with the current probe disconnected, and characterizing the response of the current probe using the output current of the current probe and the first and/or second output currents of the through.

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 stimulus signal to the impairment network; estimating an impairment transfer function corresponding to the impairment based on the applied stimulus signal; and correcting the measured electrical signal using the impairment transfer function to determine the electrical signal output from the DUT.

Abstract: A method is provided for extending dynamic range of a receiver. The method includes receiving a known input signal at the receiver, detecting a first output signal in response to the known input signal, and determining a correction function based on the first output signal and the known input signal for compensating for non-linear distortion introduced by the receiver. The method further includes receiving an unknown input signal at the receiver, detecting a second output signal in response to the unknown input signal, and applying the correction function to the second output signal in a time domain to recover the unknown input signal.

Abstract: A real-time spectrum analyzer for measuring time domain data of an input signal includes an ADC, a resampler and a density histogram memory unit. The ADC has a first sample rate and is configured to acquire and digitize the input signal at the first sample rate to provide first samples. The resampler has a second sample rate and is configured to acquire the first samples at the second sample rate to provide second samples grouped in sample sets, where the second sample rate is selected so that each sample set includes an integer number of second samples per an integer number of periods at a frequency of interest of the input signal. The density histogram memory unit is configured to store at least a portion of the second samples output by the resampler for generating a continuous real-time gap-free density histogram corresponding to the time domain data.

Abstract: A method of operating a data processing system having a touch enabled display screen to alter the value of a specified variable in the data processing system is disclosed. A value control is provided on the display screen to alter the variable. The value control has an increment tap region, a decrement tap region, and a drag region. The data processing system recognizes gestures in these regions and changes the variable in response to the gestures by an amount that is determined by the gesture. The drag gesture is characterized by a drag direction and a drag length, the drag direction depending on whether the drag gesture is performed toward the increment or decrement tap regions. The value control is advantageous for small display screens.

Abstract: Filterbank windowing and Fourier transformation are used to distinguish sub-bands of interest from other sub-bands of an input signal. The sub-bands of interest are selected and then subjected to additional windowing and Fourier transformation.

Abstract: A printed circuit board (PCB) includes a stack of core layers disposed one over another, and electrically conductive interconnects extending vertically in the stack. Each of the core layers includes a substrate having opposite major surfaces, an electrically conductive active trace extending along at least one of the major surfaces, and an indicium. The stack also has an exposed edge where the indicia of the layers are together revealed. The indicia provide identifying and/or fiducial information about the PCB.

Abstract: An electrical signal is processed by digitizing the electrical signal to produce a stream of digitized data in the time domain, wherein the stream has an original frequency spectrum, transmitting the stream to N signal paths (N>1), and down-converting and filtering the stream in each of the N signal paths to produce N streams of digitized data in the time domain, wherein the N streams have N frequency spectra, respectively, and the N frequency spectra cover N different portions of the original frequency spectrum, respectively.

Abstract: A test system measures parameters of a device under test (DUT), including a transistor. The test system includes a first voltage source unit for supplying a gate voltage; a second voltage source unit for supplying one of a drain voltage or a source voltage, the second voltage source having a current measurement device for detecting one of a drain current or a source current flowing through the transistor, respectively; a feedback unit for outputting a feedback current, based on the one of the drain or source currents; and an error amplifier for outputting a feedback control signal, based on comparison of the feedback current and a target current value. The first voltage source unit adjusts the gate voltage based on the feedback control signal so that the one of the drain or source currents converges to match the target current value.

Abstract: A method of operating a data processing system running a visual programming language program development system to represent an instrument having a plurality of controls disposed in a layout pattern relative to one another in a visual program. The instrument block that corresponds to the instrument includes a GUI control panel display having a plurality of virtual controls and a connection region. Each virtual control causing the instrument to execute a function that alters the physical state of the instrument. The connection region is associated with the GUI control panel display. The connection region has a pin that is associated with one of the virtual controls and provides a programming interface for connections to other pins in the visual program. The association between the one of the virtual controls and the pin is provided in response to user input during a design phase of the program.

Abstract: An electromagnetic interference (EMI) signal is processed by digitizing the EMI signal, generating a plurality of overlapping time records from the digitized EMI signal, applying a window function to the plurality of overlapping time records to produce a plurality of modified time records, wherein the window function has a substantially flat top, and performing a fast Fourier transform (FFT) on each of the modified time records to produce a plurality of corresponding amplitude envelopes.

Abstract: A measurement apparatus, for example a digital oscilloscope, receives an amplitude modulated (AM) signal comprising a baseband signal, having a baseband waveform, modulating a carrier signal, and reconstructs the baseband waveform. The measurement apparatus: samples the AM signal at a sampling rate which produces a plurality of data samples for each period of the carrier signal; determines the amplitude of the baseband signal for each of a plurality of periods of the carrier signal from at least some of the plurality of data samples for each period; and reconstructs the baseband waveform from the amplitudes of the baseband signal for each of the plurality of periods of the carrier signal. The measurement apparatus may display the reconstructed baseband waveform on a display device.

Abstract: A system and method supply a test signal having a first tone at a first RF frequency and a second tone at a second RF frequency to a frequency converter; provide a local oscillator (LO) signal to the frequency converter, wherein an IF output signal of the frequency converter is supplied to an input of an intermediate frequency (IF) filter, in response to which the IF filter provides a filtered IF output signal; for each of N>1 different LO frequencies, measure the filtered IF output signal at a pair of IF frequencies corresponding to differences between the first and second RF frequencies and the LO frequency, where the measurements of the filtered IF output signal measure time-invariant phase; and ascertain N?1 values of phase dispersion D of the IF filter at N?1 corresponding IF frequencies from the N measurements of the filtered IF output signal at the N different LO frequencies.

Abstract: A direct digital synthesizer (DDS) includes a phase increment calculator that determines a phase increment for a selected frequency; a phase accumulator that accumulates the phase increment over time and provides an accumulated phase value; a converter that converts the accumulated phase value to an analog signal at the selected frequency; and a phase preset calculator that determines a phase preset value for the selected frequency. The phase accumulator resets the accumulated phase value to the phase preset value at a transition to the selected frequency in a phase coherent mode.

Abstract: A method of operating a data processing system to generate a diagram indicative of an experimental setup includes a device to be tested (DUT) and a plurality of test instruments is disclosed. The method includes detecting a first test instrument that is connected to the data processing system and determining connection points to the first test instrument. A script that specifies tests for the DUT using the plurality of test instruments and includes instructions specifying measurements to be made by the first test instrument is examined. A first connection between the DUT and the first test instrument is determined. An initial diagram on a display controlled by the data processing system is generated. The initial diagram includes a first node representing the first test instrument, a second node representing the DUT and a line representing the first connection between the first and second nodes.

Abstract: A logic analyzer and method of logic analysis: detect via one or more probes a plurality of signals associated with a double data rate (DDR) random access memory (RAM); analyze the detected signals to identify a plurality of Transactions for the DDR RAM pertaining to a plurality of Operations for the DDR RAM; select one of the plurality of Operations for the DDR RAM; identify all of the Transactions for the DDR RAM which pertain to the selected Operation; and display indications of all of the Transactions for the DDR RAM which pertain to the selected Operation together on a display window of a display device.

Abstract: An illumination system and method for operating the same is disclosed. The illumination system includes a spatial light modulator (SLM), first and second optical systems, a controller and a mask. The SLM is positioned to receive an incident light beam. The first optical system images light leaving the SLM onto the mask that blocks part of the light. The second optical system images light leaving the mask onto a sample to be illuminated. The controller causes the SLM to display an SLM pattern that generates an illumination beam and a spurious light beam from the incident light beam, the illumination beam passing through the mask, wherein the mask includes a fixed part having a plurality of openings and a moveable part that moves in relation to the fixed part and that includes an opening.

Abstract: A method of operating a data processing system running a visual programming language program development system to represent an instrument having a plurality of controls disposed in a layout pattern relative to one another in a visual program. The instrument block that corresponds to the instrument includes a GUI control panel display having a plurality of virtual controls and a connection region. Each virtual control causing the instrument to execute a function that alters the physical state of the instrument. The connection region is associated with the GUI control panel display. The connection region has a pin that is associated with one of the virtual controls and provides a programming interface for connections to other pins in the visual program. The association between the one of the virtual controls and the pin is provided in response to user input during a design phase of the program.

Abstract: An oscilloscope system includes a current probe, a processing unit and a display unit. The current probe includes a high and low gain signal paths for receiving simultaneously a signal of interest from a device under test (DUT), and to output amplified small and large current portions of the signal of interest, respectively. The processing unit receives first and second digitized data corresponding to the amplified small and large current portions output by the high and low gain signal paths, respectively, and processes the first and second digitized data for display as zoomed-in and zoomed-out waveform data, respectively. The display unit displays simultaneously a zoomed-in waveform in a first display window, based on the zoomed-in waveform data, and a zoomed-out waveform in a second display window, based on the zoomed-out waveform data, using the same time scale. The small current portion is less than a predetermined threshold.

Abstract: Disclosed is an improved real-time oscilloscope (“IRTO”) for generating a fast worst-case real-time eye diagram from an input signal. The IRTO may include signal conditioning circuitry, a digitizer, an acquisition memory, a clock and data recovery (“CDR”) module, a worst-case real-time eye diagram rendering (“WRTER”) module, and a display.