Abstract: A method of detecting image quality in a wavelet transform-encoded image includes receiving wavelet transform-encoded image data partitioned into tiles, each tile partitioned into a number of subbands, evaluating a number of wavelets in fewer than the number of subbands, assigning a measure to each of the subbands evaluated for each tile, using the measures to determine a perceptual visual quality score for the image, and adjusting operation of the decoder based upon the perceptual visual quality score. A decoding system includes a memory to receive wavelet-transformed compressed image data having a predetermined number of subbands, and a decoder to determine a number of wavelet coefficients in a subset of the predetermined number of subbands, measure an amount of blur in the image data based upon the number of wavelet coefficients, and adjust a decoding process based upon the amount of blur.

Abstract: This disclosure relates generally to test and measurement instruments structured to detect that a series of events occurred, and structured to generate a trigger signal in response to detecting that a final event in the series of events occurred. The trigger may be generated based on a timeout signal, or based on another event, trigger, or signal. Stored data in the acquisition memory may be marked relative to the detection of the final event. An external forced timeout signal may control which in a series of events is marked as a final event. The triggering on final event may be enabled after another trigger is satisfied, and may be used as one of many different types of triggers.

Abstract: Embodiments of the present invention provide techniques and methods for improving signal-to-noise ratio (SNR) when averaging two or more data signals by finding a group delay between the signals and using it to calculate an averaged result. In one embodiment, a direct average of the signals is computed and phases are found for the direct average and each of the data signals. Phase differences are found between each signal and the direct average. The phase differences are then used to compensate the signals. Averaging the compensated signals provides a more accurate result than conventional averaging techniques. The disclosed techniques can be used for improving instrument accuracy while minimizing effects such as higher-frequency attenuation. For example, in one embodiment, the disclosed techniques may enable a real-time oscilloscope to take more accurate S parameter measurements.

Abstract: A mechanism is included for receiving a phase modulated optical signal. The phase modulated signal is modulated by a remote electrical test signal at a sensor head. A reference optical signal is also received. A phase difference between the phase modulated optical signal and the reference optical signal is then determined. The phase difference is employed to recover the remote electrical test signal from the sensor head. The phase difference may be determined by employing a phase modulator in a controller that tracks a phase modulator in the sensor head. The phase difference may also be determined by comparison of the signals in the complex signal domain.

Abstract: An arbitrary waveform generator including a first processor configured to output first digital data, a second processor configured to output second digital data, a first digital-to-analog converter to receive the first digital data from the first processor and output a first analog signal representing the first digital data, a second digital-to-analog converter to receive the second digital data from the second processor and output a second analog signal representing the second digital data, a system phase detector to receive the first analog signal and the second analog signal and determine a phase difference between the first analog signal and the second analog signal, and a controller configured to receive the phase difference from the system phase detector and determine a delay time for the first processor to delay an output of third digital data based on the phase difference.

Abstract: A network oscilloscope, including a network interface configured to receive a stream of network data, one or more processors, and a display. The one or more processors generate a timestamp for each data packet parsed from the stream of network data, extract a portion of information from each of the data packets received from the stream of network data, the portion of information being less than an entirety of information in each data packet, and generate a data record indicating extracted information and a timestamp for each data packet parsed from the stream of network data. The display configured to display at least a portion of the data record.

Abstract: An arbitrary waveform generator including a first processor configured to output first digital data, a second processor configured to output second digital data, a first digital-to-analog converter to receive the first digital data from the first processor and output a first analog signal representing the first digital data, a second digital-to-analog converter to receive the second digital data from the second processor and output a second analog signal representing the second digital data, a system phase detector to receive the first analog signal and the second analog signal and determine a phase difference between the first analog signal and the second analog signal, and a controller configured to receive the phase difference from the system phase detector and determine a delay time for the first processor to delay an output of third digital data based on the phase difference.

Abstract: A signal acquisition probe stores compressed or compressed and filtered time domain data samples representing at least one of an impulse response or step response characterizing the signal acquisition probe. The compressed or compressed and filtered time domain data samples of the impulse response or the step response are provided to a signal measurement instrument for compensating the signal measurement instrument for the impulse or step response of the signal measurement instrument.

Abstract: A test and measurement instrument includes a coefficient storage facility coupled to a programmable filter. The coefficient storage facility is configured to store at least two pre-determined filter coefficient sets, and configured to pass a selected one of the at least two pre-determined filter coefficient sets to the filter based on a measurement derived using a compensation oscillator. The measurement may include clock delay and clock skew. In some examples the test and measurement instrument may additionally adjust clock delay and/or clock skew in addition to selecting appropriate filter coefficients.

Abstract: A test and measurement probe coupler that may include a substrate, a first signal tap conductor, a first signal contact, a first ground tap conductor, and a first ground contact. The first signal tap conductor may extends a first length along the substrate. The first signal contact may be electrically coupled to the first signal tap conductor, and the first ground tap conductor may extend a second length along the substrate. The first ground tap conductor may be substantially parallel to the first signal tap conductor. The first ground tap conductor may be disposed in a first lateral direction away from the first signal tap conductor, and the first ground contact electrically may be coupled to the first ground tap conductor.

Abstract: A flexible resistive tip cable assembly includes a probe Radio Frequency (RF) connector structured to receive a RF differential signal and a testing connection assembly. A coaxial cable is structured to conduct the RF differential signal between the probe RF connector and the testing connection assembly. The coaxial cable includes a cable for conducting the differential signal, and a plurality of magnetic elements positioned along a length of the cable and structured to isolate the differential signal from common mode interference. The magnetic elements are separated from adjacent magnetic elements by a gap with elastomeric elements is positioned in each gap to provide cable flexibility. The assembly may also include an Electrically Erasable Programmable Read Only Memory (EEPROM) loaded with an attenuation associated with the flexible resistive tip cable assembly for use in signal testing by a device coupled to the testing connection assembly.

Abstract: A test and measurement instrument, including a splitter configured to split an input signal into two split input signals and output each split input signal onto a separate path and a combiner configured to receive and combine an output of each path to reconstruct the input signal. Each path includes an amplifier configured to receive the split input signal and to compress the split input signal with a sigmoid function, a digitizer configured to digitize an output of the amplifier; and at least one processor configured to apply an inverse sigmoid function on the output of the digitizer.

Abstract: A test-and-measurement instrument is described. A state machine, corresponding to a regular expression, can be stored in the test-and-measurement instrument. The state machine can be modified to reflect a trigger condition received from a user. The modified state machine can then be used to invoke a trigger when the condition is met in the bits of a bit stream.

Abstract: Disclosed is a mechanism of operating a Networked Media Open Specifications (NMOS) Application Programming Interface (API) at a node controlling a local device including a local receiver. A flow message is received via the NMOS API. The flow message contains a flow state of a target receiver at a remote node. A local receiver at the local device is configured to mirror the flow state of the target receiver at the remote node. The NMOS API then notifies a registry with an updated flow state of the local receiver at the local device.

Abstract: A continuously or step variable passive noise filter for removing noise from a signal received from a DUT added by a test and measurement instrument channel. The noise filter may include, for example, a splitter splits a signal into at least a first split signal and a second split signal. A first path receives the first split signal and includes a variable attenuator and/or a variable delay line which may be set based on the channel response of the DUT which is connected. The variable attenuator and/or the variable delay line may be continuously or stepped variable, as will be discussed in more detail below. A second path is also included to receive the second split signal and a combiner combines a signal from the first path and a signal from the second path into a combined signal.

Abstract: A test probe tip can include a resistive element coupled with a tip component. The resistive element can include a resistive layer disposed on an exterior surface of a structural member of the resistive impedance element. In embodiments, the resistive element can be configured to form a structural component of the test probe tip without an insulating covering applied thereto. Additional embodiments may be described and/or claimed herein.

Abstract: A sensor head of a test and measurement instrument can include an input configured to receive an input signal from a device under test (DUT), an optical voltage sensor having signal input electrodes and control electrodes or one set of electrodes, wherein the input is connected to the signal input electrodes, and a bias control unit connected to the control electrodes and configured to reduce an error signal or the input signal bias control signal are electrically combined and applied to a single set of electrodes.

Abstract: Embodiments of the present invention provide an improved cable assembly for connecting an electrical test and measurement probe to a device under test. One end of the probe is connected to a device under test (“DUT”), while the other end is connected to the instrument through one or more cables. To prevent mechanical stresses to the probe-DUT interface caused by the cables' resistance to bending and twisting, embodiments of the improved cable assembly use one or more pliable spines to hold the cable assembly in position after it has been bent or twisted. This provides a more secure connection to the DUT and prevents damage to the probe-DUT interface. Each spine is anchored to the tip of the probe, and may be further secured by an outer housing or additional anchors. A flexible boot may surround the cable assembly and/or outer housing, further protecting the cables from damage. Alternatively, one or more spines may be placed inside the boot.

Abstract: An electro-optical sensor comprises an optical input configured to receive an optical carrier via an upstream fiber. The electro-optical sensor also includes an optical modulator configured to modulate an electrical signal onto the optical carrier to create an optical signal. The electro-optical sensor further includes an optical output configured to transmit the optical signal via a downstream fiber. The electro-optical sensor employs a variation output configured to transmit variation data indicating variation in the received optical carrier to support compensation for corresponding variation in the optical signal.

Abstract: Disclosed is a mechanism for limiting Intersymbol Interference (ISI) when measuring uncorrelated jitter in a test and measurement system. A waveform is obtained that describes a signal. Such waveform may be obtained from memory. A processor then extracts a signal impulse response from the waveform. The processor selects a window function based on a shape of the signal impulse response. Further, the processor applies the window function to the signal impulse response to remove ISI outside a window of the window function while measuring waveform jitter. The window function may be applied by applying the window function to the signal impulse response to obtain a target impulse response. A linear equalizer is then generated that results in the target impulse response when convolved with the signal impulse response. The linear equalizer is then applied to the waveform to limit ISI for jitter measurement.