Abstract: A rectangle marker on a display of a signal analyzer simultaneously designates time and frequency intervals of data from a signal under test for analysis. The data of the signal under test is displayed as a graph having time and frequency axes. Sub-graphs show data designated by the rectangle marker as processed in the time domain, frequency domain and modulation domain. The resulting display provides an overview of the signal under test and simultaneously provides displays of measurements and analyzes for a designated portion of the data.

Abstract: A method of measuring peak signal to noise ratio (PSNR) of full color video, both total and component contributions as well as providing PSNR full color and component maps includes converting the components of the full color video for both reference and impaired video signals to RGB values, and computing the error energy for each of the G, B and R channels between the reference and impaired video signals. Each component contribution to the error for the full color video components is assessed by setting the other components to a reference value, such as zero. Also the total full color PSNR is computed in RGB. Finally a color residual PSNR map is generated and displayed together with the computed PSNR results to enable a user to visualize where the significant impairments occur in the impaired video.

Abstract: A spectrogram mask trigger is generated in response to multiple or complex frequency events within a signal being monitored. A sequence of frequency masks over a period of time is generated according to a frequency trajectory, frequency hops or other complex frequency events expected in the signal to form a spectrogram mask. The spectrogram mask is then applied to multiple spectra or spectrogram of the signal to determine whether an anomalous frequency event has occurred within the time period or to identify a particular frequency pattern within the signal. Depending upon the results of the spectrogram mask application, the spectrogram mask trigger is generated for storing a block of data from the signal surrounding the triggering event for further analysis.

Abstract: A method of drawing a waveform image in a no dead time acquisition system, where consecutive drawing frames overlap, uses a master/slave relationship between two fast rasterizers. The master rasterizer draws a first display frame in response to a first trigger event in a trigger signal derived from an input signal. The slave rasterizer draws a second display frame in response to a subsequent trigger event in the trigger signal. The portion of the second display frame that duplicates data contained in the first display frame is either (a) suppressed when the first and second display frames are combined to form the waveform image or (b) displayed in a different shade/color.

Abstract: A simple, integrated control for pan and zoom of a display of data represented by a very long data record is in the form of a control knob having an outer ring for controlling pan and an inner knob for controlling a zoom factor. A zoom function is turned ON either by turning the inner knob (setting the zoom factor to a default value) or by (i) pressing an adjacent zoom or pan button or (ii) turning the outer ring (setting the zoom factor to a prior value when the zoom function was turned OFF). The zoom function may be turned OFF by turning the inner knob to set the zoom factor to 1× or by pressing the zoom button. The outer ring has individual positions divided into two groups: one group for controlling pan rate within a zoom window displaying a portion of the very long data record defined by a zoom box within a main window displaying the very long data record; and the other group for controlling pan rate of the zoom box within the main window for rapid movement from one end of the record to another.

Abstract: A waveform compression and display technique saves both a peak detected version (background version) and a decimated/lowpass filtered version (foreground version) of a sampled electrical signal. The two versions are displayed simultaneously overlaid together in a contrasting manner so as not to obscure information contained in either of them. The lowpass filtered version uses a series of simple lowpass filters with decimation to produce a single data stream from a plurality of data streams derived from the sampled electrical signal. The single data stream may then be subjected to additional filtering, such as a cascaded integrator-comb filter, to obtain a desired frequency bandwidth. When displayed, the peak detect pixels adjacent the decimated/lowpass filtered pixels may be adjusted in intensity so that the low frequency information of the lowpass filtered waveform is not lost, while the peak detect pixels further from the lowpass filtered pixels are intensified to highlight the high frequency information.

Abstract: An encoded serial data bit error analyzer captures the actual waveform of an encoded serial data stream associated with a bit error so that a user may readily validate the cause of the bit error. An encoded serial data stream decoder in the analyzer is modified to provide a signal for a trigger system when a characteristic of a bit error failure is detected. A power splitter produces a pair of incident encoded serial data streams from a programmable test signal, one of which is input to a device under test and the other is input to the analyzer. A re-transmitted encoded serial data stream from the device under test is input to another channel of the analyzer. The encoded serial data stream decoder provides an “error detected” output when a condition occurs in the re-transmitted encoded serial data stream indicative of a bit error. The “error detected” output is used as a trigger signal to capture the incident and re-transmitted encoded serial data waveforms surrounding the detected bit error.

Abstract: A multiple probe acquisition system, such as for use with a value instrument, uses probes where each probe includes an acquisition circuit for acquiring from a circuit under test an electrical signal as digital data at a high rate, and then transferring the digital data from the probe to the instrument at a lower rate over a data bus for processing and display. The probe may be used to acquire analog waveforms or logic data from the electrical signal. The probe provides a very low input capacitance to the circuit under test, minimizing signal distortion, and is relatively inexpensive. The probes are time aligned by detecting when one of the probes generates a trigger, and timing the other probes to stop acquisition simultaneously so the data is synchronized among the probes.

Abstract: A time synchronized measurement system has a master device and a slave device. The master device and the slave device each have a time measurement device for assigning a corresponding time of sending and/or receiving a piece of measurement information. The master device also has a reference clock pulse-generating device for transmitting a reference clock signal to the slave device. The reference clock signal is modulated by a piece of information on a common time basis for the master device and the slave device.

Abstract: A method of measuring instantaneous signal-dependent nonlinear distortion in a system under test in response to a test signal having a varying frequency sinusoidal component, such as a swept frequency signal or a multi-burst signal, uses a time window to locate a frequency of interest in the corresponding varying frequency component of a signal output from the system under test. Once the location of the frequency of interest is located in the output signal, a spectrum of the portion of the output signal within the time window is generated and the magnitudes of the spectral peaks, including the spectral peak for the frequency of interest or nominal frequency and all isolated peaks representing distortion frequencies, are measured. The amount of distortion is calculated as a ratio of the square-root of the sum of the magnitudes of the distortion frequencies to the magnitude of the nominal frequency.

Abstract: A system and method for automatic measurement of video parameters for a video sequence using a video processor that has a software waveform monitor implemented as an integral part of a video processing application run by the video processor. Each frame of the processed video sequence, either in realtime as processed by the video processor, in near realtime after storage by the video processor in a storage device, or in the background for each video sequence stored in the storage device, is analyzed against specified parameters for legalization and/or color balancing of the video sequence. The analysis results may be reported as a display in several forms—an error image map, an error log, a timeline graphic, etc. The analysis results may also be provided to the video processor for automatic correction of the video sequence when the specified parameters are not satisfied.

Abstract: A modulation domain trigger generator demodulates a modulated input signal to extract information content, and a trigger is generated from the extracted information content in response to specified trigger criteria. The modulation domain trigger generator may be combined with a plurality of different types of trigger generators, including frequency domain and time domain trigger generators, to process the input signal in response to different trigger criteria to produce more than one trigger. The different trigger outputs may be combined to produce an acquisition trigger to acquire data surrounding an anomalous or identifiable event within the input signal.

Abstract: A method of configuring a filter for a data stream organized in frames in a protocol tester that is simple without requiring any knowledge of an internal protocol configuration provides the frames partially decoded in an overview display. A user searches the frames for a desired content and selects one of the frames having the desired content. The selected frame is displayed in a fully decoded view. A filter rule is derived from the desired content for configuring the filter. The filter rule may be further defined by modifying parameters from the fully decoded view of the selected frame. The configured filter is applied to all the frames to produce a set of filtered frames.

Abstract: A method of despreading modulated signals with low noise to demodulate a sum of spread signals from a base station of a mobile phone system provides the sum of spread signals to several paths. A despreading circuit in each path despreads the sum of spread signals by respective spreading codes. The despread signals are separated into channels and symbols for each channel are estimated on each path. The symbols are modulated by applicable Walsh codes corresponding to the respective channels, added and spread to produce an estimated spread signal corresponding to the spreading code for each path. Then the sum of spread signals is despread again on each path after the estimated spread signals of other paths are subtracted from the sum of spread signals so that the noise due to interference between the spreading codes is reduced.

Abstract: Time correlation of signal to distortion characteristics is achieved by acquiring time domain data for a frequency band representing a communication signal, the communication signal having multiple channels. The time domain data is simultaneously converted to frequency and demodulation domain data in sequential time blocks. The frequency and demodulation domain data are processed to obtain respectively frequency and demodulation domain measurements. The resulting measurements are displayed simultaneously as a function of time for all the time blocks and/or for a selected one of the time blocks. An ACLRogram display provides a display having a time axis and a frequency axis in the form of bars spanning the frequency band for each time block with each bar being divided into frequency sub-bands representing a main channel and adjacent side channels, the shading of each segment of the bar representing a measurement value for that segment.

Abstract: A self-adjusting hold-off trigger circuit and method detects a threshold crossing between consecutive samples of a digitized input signal as edge events, identifies the crossing as a qualified trigger event if the crossing is in a desired direction based upon trigger criteria, and provides a trigger output when the qualified trigger event occurs greater than an approximate average or peak time after a preceding edge event.

Abstract: A method of characterizing the frequency response of a frequency translation device over a wide IF bandwidth is based on a two-dimensional model to generate calibration data for a device at run-time. The model is a function of a center frequency and frequency offset for a plurality of center frequencies over a wide system bandwidth to produce a frequency response at each center frequency. The frequency responses at each center frequency are scaled and normalized relative to a reference frequency and stored.

Abstract: An instrumentation receiver architecture for processing an RF signal has a dual-IF channel architecture, a low-band IF channel and a high-band IF channel, and a tunable oscillator, such as a yttrium-iron-garnet (YIG) tunable oscillator (YTO), a voltage controlled oscillator (VCO), a bank of VCOs and the like, providing a different mixing frequency range to each channel, generally a higher frequency range to the high-band IF channel than to the low-band IF channel. At the input to the high-band IF channel is a bank of preselection filters for selecting a frequency band from the RF signal for processing by the high-band IF channel. A switch selects the output from one of the low-band and high-band IF channels for further processing.

Abstract: A method and protocol tester for decoding data for the performance of a measurement task, which data is encoded in accordance with a protocol description, includes modifying the protocol description with respect to the measurement task by compressing protocol elements that are of no relevance to the measurement task and decoding the encoded data according to the modified protocol description to provide only decoded data relevant to the measurement task. The decoded data may be filtered before further processing according to a filter condition determined by the measurement task. Alternatively the filter condition may be installed as part of the modified protocol description. Then additional filtering may be applied when there are further filter conditions determined by the measurement task. The result is a protocol tester that permanently stores the protocol description while allowing modification of the protocol description for each measurement task, reducing storage and calculation requirements.

Abstract: The present invention relates to a circuit arrangement with which a communication that is subdivided into functional layers is processable by a first layer for a higher layer and/or by a higher layer for the first layer, the first layer being formed by a physical layer and the circuit arrangement featuring at least one port which allows a communication directly with a layer that is higher than the first layer without the communication previously having to pass through the first layer.