Abstract: A fast temporal alignment estimation method for temporally aligning a distorted video with a corresponding source video in order to perform accurate video quality measurements transforms each video into a corresponding signature curve by calculating a data point for each frame. The data points are calculated as a cross-correlation between a present frame and a subsequent frame in the video. The signature curves are then matched using a normalized cross-correlation algorithm to compute the temporal misalignment between the videos so that the video signals may be temporally aligned. Fast spatial alignment may then be performed and accurate video quality measurements made.

Abstract: A real time multi-channel digital storage oscilloscope acquires a relatively long data record for each channel in an acquisition memory and processes the data of the relatively long data record to search for predetermined events. Upon detection of such a predetermined event, circuitry generates an event detect signal, and data comprising an acquisition frame surrounding the event is applied to a waveform processing and display system. The relatively long data record can be replayed in order to perform additional searches throughout the data record using different search criteria, thereby permitting multiple waveforms to be displayed simultaneously, each being captured as a result of a different user-defined event. A screen display may be programmed to display a different kind of event such as Runt signal, Overshoot, or Pulsewidth Violation in each waveform, or to display multiple occurrences of the same kind of event such as Runt signal in each waveform.

Abstract: An electrical probe for a flying leadset of a logic analyzer probe has coaxially aligned internal elements enclosed in an insulating cover. The probe has an electrically conductive contact having contact fingers extending in one direction from a support member and a contact member extending in the opposite direction. A sleeve abuts the contact member and receive a center conductor of a conductive cable that is secured in the contact member. The insulating cover has a contact cover portion and a over-mold portion that are chemically bonded together. The contact fingers are positioned in the contact cover and the over-mold portion encapsulates the rest of the probe. The contact fingers are aligned parallel with one side of a square aperture formed in the contact cover. A resistive element may be interposed between the contact member and the sleeve.

Abstract: A modulation analyzer includes a smoothing processor which processes the coordinates of symbol landing points to generate a curve that optimally fits the landing points under a selected criterion.

Abstract: A method and apparatus for non-intrusive measurement of end-to-end properties of network flows uses a passive approach. An ingress monitor non-intrusively intercepts data units as they enter a network path through a network. Likewise an egress monitor non-intrusively intercepts the same data units as they leave the same network path. Each monitor generates a time stamp for each intercepted data unit using a common clock and derives a unique signature for each data unit such that the same data unit has the same signature at the entry as at the exit. Additionally each monitor counts the number of packets received from the network flow at the ingress and egress respectively. The signature, time stamp and packet counter value form an entry which is retained in an entry queue in each monitor. A data correlator coupled to an out-of-band network to which the monitors also are coupled periodically pulls a list of entries from each monitor and correlates the lists by matching signatures.

Abstract: A robust technique for estimating camera motion parameters calculates the motion vectors for a current frame vis a vis a previous frame using a multi-scale block matching technique. The means of the motion vectors for the current and the previous frames are compared for a temporal discontinuity, the detection of such temporal discontinuity as a temporal repetition, such as frozen field or 3:2 pulldown, terminating the processing of the current frame with the camera motion parameter estimate for the previous frame being used for the current frame. Otherwise motion vectors for spatially flat areas and text/graphic overlay areas are discarded and an error-of-fit for the previous frame is tested to determine initial parameters for an iterative camera motion estimation process. If the error-of-fit is less than a predetermined threshold, then the camera motion parameters for the previous frame are used as the initial parameters, otherwise a best least squares fit is used as the initial parameters.

Abstract: An adjustable delay line phase shifter is configured as a microstrip transmission line having a M×N matrix of conductive elements mounted on a insulating substrate. The squares are connected together using conductive members, such as gold ribbon or wire bonds, in a pattern that produces a desired amount of phase shift.

Abstract: A measurement probe has housing in which are disposed a spring loaded coaxial probe assembly and a pressure sensor. The probe assembly is formed from a semi-rigid coaxial cable having a probing tip formed at one end and a coaxial connector at the other end. The pressure sensor has first electrically conductive contact secured and electrically coupled to the semi-rigid coaxial cable and a second electrically conductive contact positioned and secured within the internal cavity of the housing. The probing tip is coupled to electrical ground via a control module when the housing is in a first position and the probing tip is coupled to the input circuitry of the measurement test instrument via the control module in response to an activation signal generated by the pressure sensor in response to movement of the housing to a second position and coupled to the control module.

Abstract: A method for representing a modulated signal vector by determining complex coordinates for the signal vector where the complex coordinates define respective locations on a complex plane that is logically segmented into a plurality of regions, and by generating, for each logical region, a respective signal density indicative magnitude value to form a histogram of the logical regions and their respective magnitude values.

Abstract: Human vision based pre-processing for MPEG video compression uses light intensity. An input video signal is input to a contrast gain control circuit where a Gaussian pyramid is constructed. The reduced pyramid image serves as a local light level. The reduced pyramid image also is processed to obtain a global light center. The difference between the local light level and the global light center is used as an index to a lookup table that provides a local gain control signal. The local gain control signal and a global gain control signal input to the contrast gain control circuit are used to multiply a Laplacian image derived from the input image, the resulting modified Laplacian image being subtracted from an equivalent lowpass filtered video image to produce a pre-processed output video signal having reduced bandwidth for input to an MPEG2 compressor.

Abstract: A measurement probing system has a measurement probe having a housing, spring loaded coaxial probe assembly and a pressure sensor that generates a resistive activation signal in response to movement of the housing in relation to the spring loaded coaxial probe assembly. The activation signal is applied to control circuitry in a control module for generating an output signal to drive an RF relay to couple the probing tip of the measurement probe from electrical to input circuitry of a measurement test instrument. The control circuitry further includes a TTL buffer circuit for generating the output signal in response to a TTL logic signal from a controller for automated testing of a device under test.

Abstract: A butt joined electrical apparatus has an open end face carrier or housing on which is positioned an electrical element. An electrical device and a coplanar transmission structure is formed on the electrical element with the coplanar transmission structure disposed toward the open end face of the carrier or housing. The electrical device coupled an electrical signal to and from a mating opto-electrical apparatus or housing. The coplanar transmission structure is independently aligned in three mutually perpendicular directions and in a proximate abutting relationship with another matching coplanar transmission structure formed on an opto-electrical element of the mating opto-electrical apparatus or housing. The electrical and opto-electrical apparatuses are independently positioned and mechanically joined together with the matching coplanar transmission structures electrically coupled together via substantially flat electrical conductors.

Abstract: Initial mask and waveform positions on a display screen may be determined by an AUTOSET TO MASK function. Upon detection of violations that occur after the AUTOSET TO MASK function is complete, control for further alignment of the waveform under test and the mask is assumed by an AUTOFIT TO MASK function. Comparison of the mask pixels and waveform pixels to detect collision between a waveform pixel and a mask pixel (i.e., a mask violation) is performed substantially in real time, as the pixels are being composited into the raster memory by the rasterizer. In the event of a mask violation, a mask violation signal is generated. In a further embodiment of the invention, in response to the mask violation signal, the AUTOFIT TO MASK function uses display rasterization to automatically redraw the waveform at a new location, until the waveform fits within the mask.

Abstract: The invention involves storing information about the probe frequency response in the probe itself. The information preferably consists of a set of one or more characteristic frequency response data points. Each data point includes at least the gain of the probe at a given frequency. More preferably, each data point includes the complex transfer characteristic of a probe (S21 in FIG. 2) and optionally the complex output reflectivity of the probe (S22 in FIG. 2) and the frequency (F in FIG. 2) at which the data applies. A variable number of frequency points can be stored, as necessary, to adequately describe the probe's response. The probe also preferably stores a header containing the number of stored data points. The invention readily extends to probes having multiple gain settings or multiple bandwidth settings, by simply storing multiple sets of S21, S22 and F data.

Abstract: A butt joined opto-electrical apparatus has an open end face carrier or housing on which is positioned an opto-electrical element. An opto-electrical device and a coplanar transmission structure is formed on the opto-electrical element with the coplanar transmission structure disposed toward the open end face of the carrier or housing. The opto-electrical device is coupled to receive and optical signal from an optical waveguide. The coplanar transmission structure is independently aligned in three mutually perpendicular directions and in a proximate abutting relationship with another matching coplanar transmission structure formed on an electrical element of a mating electrical apparatus or housing. The opto-electrical and electrical apparatus are independently positioned and mechanically joined together with the matching coplanar transmission structures electrically coupled together via substantially flat electrical conductors.

Abstract: A high impedance attenuator for use in a test and measurement instrument employs compensation to adjust the low frequency attenuation to match the high frequency attenuation exhibited by the attenuator, rather than attempting to adjust the high frequency attenuation exhibited by the attenuator. In an alternate embodiment of the invention, compensation to adjust low frequency attenuation is employed in a feedback loop and an opposite compensation is applied in a parallel attenuation stage to stabilize the input resistance. In yet another embodiment of the invention, compensation to adjust low frequency attenuation is employed by means of an R-C time constant of an additional R-C circuit in a feed forward loop. This additional time constant is matched to the R-C time constant of the input R-C network. The input resistance of the attenuator is not changed.

Abstract: An electronic instrument with a housing in the form of a rectangular body. The housing has a front panel with a display screen, and opposed side panels extending perpendicularly from the front panel to a rear panel. The housing defines a cavity adjacent to the rear panel and at least one of the side panels. The cavity includes a recessed panel portion having attached electronic connectors, so that cables connected to the connectors can flex to avoid protruding from the side panel to facilitate rack mounting, and may extend without protruding from the rear panel for bench usage. A circuit board to which the connectors and a microprocessor are connected may be oriented parallel to the rear panel, allowing a limited front-to-rear depth for the housing.

Abstract: A butt joined electronic module has first and second coplanar transmission structures that are independently aligned in a proximate abutting relationship. The coplanar transmission structures are formed on respective first and second electrical elements that are secured on respective independently positioned and mechanically joined carrier and housing. The first and second coplanar transmission structures are electrically coupled together via substantially flat electrical conductors. The carrier and housing are bonded together as a single module.

Abstract: An expanded WIRE-OR Bus structure has a first WIRE-OR Bus arrangement and a second WIRE-OR Bus arrangement. Each of the first and second WIRE-OR Bus arrangements have connected thereto at least one driver element and at least one receiver element. An intelligent bi-directional signal coupling circuit includes a buffer element, a bus arbiter, and a bus driver amplifier. The coupling circuit couples signals between the first WIRE-OR bus and the WIRE-OR second bus, and prevents signals originating on one of the WIRE-OR buses from being coupled back to the same WIRE-OR bus.

Abstract: An improved calibration method for a vector network analyzer stores sparse calibration data, interpolates system error data from the sparse calibration data for each measurement by the vector network analyzer, and creates calibrated measurement data from the system error data and uncorrected measurement data at each measurement frequency. The sparse calibration data may be generated by measuring every Nth frequency step over a calibration frequency range greater than a specified measurement frequency range, or by measuring every frequency step over the calibration frequency range and compressing the resulting measurement data. The interpolation may be achieved by using a curve-fit algorithm, such as a parametric polynomial curve fitting algorithm.