Aspects of the invention include an equivalent-time sampling oscilloscope that receives a carrier signal, the carrier signal after it has been modulated with a repeating data pattern, and a pattern trigger signal that is synchronous with the data pattern. The carrier signal and the modulation are asynchronous, that is, they are not phase-locked in any way. The oscilloscope simultaneously samples the modulated carrier signal and quadrature phases of the unmodulated carrier signal at a plurality of timebase delays relative to the pattern trigger signal, and a plurality of times at each timebase delay. After collecting this information, the oscilloscope uses the quadrature samples to calculate phases of the unmodulated carrier signal that correspond to the samples of the modulated carrier signal. The oscilloscope then calculates a stationary representation of the modulated carrier signal by selecting samples of the modulated carrier signal that correspond to a carrier signal phase progression that would have been observed if the unmodulated carrier signal had been synchronous with the pattern trigger signal.

A photocurrent scanning system comprises a laser generating device, a focusing device, a displacement adjustment device, a bias supply device, and a measuring device. The laser generating device is used to emit a laser. The focusing device is used to focus the laser to a surface of a sample. The displacement adjustment device is used to place the sample and adjust a position of the sample, to make the laser focused onto different parts of the surface of the sample. The bias supply device is used to supply a voltage to the sample. The measuring device is used to measure a photocurrent signal flowing through the sample.

A test and measurement instrument including a digital down converter configured to receive a bus signal and output in-phase and quadrature-phase baseband component waveform data, a trace generator configured to receive the in-phase and quadrature-phase baseband component waveform data and generate at least one radio frequency versus time trace, a decoder configured to receive the at least one radio frequency versus time trace and decode the bus signal based on the at least one radio frequency versus time trace and a wireless modulation scheme, and a trigger configured to capture at least a portion of the bus signal based on the decoded bus signal.

A device and method of operation for digital compensation of dynamic distortion. The transmitter device includes at least a digital-to-analog converter (DAC) connected to a lookup table (LUT), a first shift register, and a second shift register. The method includes iteratively adjusting the input values via the LUT to induce changes in the DAC output that compensate for dynamic distortion, which depends on precursors, current cursors, and postcursors. More specifically, the method includes producing and capturing average output values for each possible sequence of three symbols using the shift register and LUT configuration. Then, the LUT is updated with estimated values to induce desired output values that are adjusted to eliminate clipping. These steps are performed iteratively until one or more check conditions are satisfied. This method can also be combined with techniques such as equalization, eye modulation, and amplitude scaling to introduce desirable output signal characteristics.

A method of deriving information from sampled data, for example, in a digital data stream, includes processing the sampled data, for example, in the high-speed data acquisition device to detect an event in the sampled data. The sampled data is converted/transformed to its first derivative representation, and zero crossing information from the first derivative representation of the sampled data is used to determine local minima and maxima and their relative offset in time to a common point in time. Information from, or derived from, the local minima and maxima and the relative offset are provided to an upstream device. The upstream device may process the local minima and maxima and the relative offset, for example, to characterize the event.

An automated zooming of a signal waveform by a measurement device is provided. Vertical parameters of a zoom window for zooming a signal waveform are automatically determined. For this purpose, an acquired measurement signal is tracked and the parameters of the zoom window are set based on the tracking of the measurement signal.

An automated zooming of a signal waveform by a measurement device is provided. Vertical parameters of a zoom window for zooming a signal waveform are automatically determined. For this purpose, an acquired measurement signal is tracked and the parameters of the zoom window are set based on the tracking of the measurement signal.

A device and method of operation for digital compensation of dynamic distortion. The transmitter device includes at least a digital-to-analog converter (DAC) connected to a lookup table (LUT), a first shift register, and a second shift register. The method includes iteratively adjusting the input values via the LUT to induce changes in the DAC output that compensate for dynamic distortion, which depends on precursors, current cursors, and postcursors. More specifically, the method includes producing and capturing average output values for each possible sequence of three symbols using the shift register and LUT configuration. Then, the LUT is updated with estimated values to induce desired output values that are adjusted to eliminate clipping. These steps are performed iteratively until one or more check conditions are satisfied. This method can also be combined with techniques such as equalization, eye modulation, and amplitude scaling to introduce desirable output signal characteristics.

To realize sampling (signal measurement) and analysis of a signal to be measured easily at low cost by capturing optical phase fluctuation even when low-speed sampling is carried out. This sampling method includes: a step for acquiring main sampling points at a repetition period equal to or less than a half of the band frequency of a signal to be measured; a step for acquiring sub-sampling points by executing sampling separately from that executed for the main sampling points; a step for acquiring an amplitude difference, a phase difference, and a frequency difference between the signal to be measured at each of the sub-sampling points and a reference signal; a step for acquiring a time difference, an amplitude difference (A), a phase difference (), and a frequency difference (f) between each of the main sampling points and each of the sub-sampling points; and a step for acquiring the amplitude fluctuation, the phase fluctuation, and the frequency fluctuation of the signal to be measured by using the time difference (t), the amplitude difference (A), the phase difference (), and the frequency difference (f) between each of the main sampling points and each of the sub-sampling points.

To realize sampling (signal measurement) and analysis of a signal to be measured easily at low cost by capturing optical phase fluctuation even when low-speed sampling is carried out. This sampling method includes: a step for acquiring main sampling points at a repetition period equal to or less than a half of the band frequency of a signal to be measured; a step for acquiring sub-sampling points by executing sampling separately from that executed for the main sampling points; a step for acquiring an amplitude difference, a phase difference, and a frequency difference between the signal to be measured at each of the sub-sampling points and a reference signal; a step for acquiring a time difference, an amplitude difference (A), a phase difference (), and a frequency difference (f) between each of the main sampling points and each of the sub-sampling points; and a step for acquiring the amplitude fluctuation, the phase fluctuation, and the frequency fluctuation of the signal to be measured by using the time difference (t), the amplitude difference (A), the phase difference (), and the frequency difference (f) between each of the main sampling points and each of the sub-sampling points.