Abstract: An adaptive multi-modal motion estimation algorithm for video compression builds a luminance pyramid for each image of a moving image sequence. From the top level image of the luminance pyramid a global motion vector is determined between images at times t and t+n. The global motion vector is used as a pivot point and to define a search area. For each block of a current top level image a search for a match is carried out around the pivot point within the search area. The resulting block motion vectors serve as initial conditions for the next higher resolution level. A refinement process results in a displaced frame difference value (DFD) for each block as an error measure. If the error measure is small, the motion vector is chosen as the motion vector for the current block. If the error measure is large, then a search within the search area around a zero motion pivot point is conducted. The motion vector that results in the smallest error measure is chosen as the motion vector for the current block.

Abstract: A flat display device, preferably of the PALC type, in which the plasma channels are formed by etching laterally-spaced slots in a spacer plate, attaching a thin dielectric sheet over the etched spacer plate, and bonding the etched spacer plate to a transparent substrate such that each channel is formed by the portion of the substrate between flanking walls formed by the etched slots in the spacer plate, adjacent flanking walls in the spacer plate, and the overlying portion of the thin dielectric sheet. In a modification, strengthening crossbars are formed between adjacent flanking walls.

Abstract: An optical system having a first order spectral range that is usable in an optical spectrum analyzer receives an broadband optical test signal and a optical calibration signal and couples the optical signals via two optically isolated paths to separate optical detectors. First and second pairs of optical fibers, with each pair having an input fiber and an output fiber, are positioned in a focal plane of a collimating optic that has an optical axis. The fiber pairs are symmetrically positioned on either side of the optical axis with the input fibers positioned on one side of the optical axis and the output fibers positioned on the opposite side of the optical axis. The input fibers receive the optical test signal and the optical calibration signal. The output optical fibers are coupled to first and second optical detectors. An optical calibration source generates second order or greater spectral lines that fall within the first order spectral range of the optical system.

Abstract: An apparatus and method for measuring delay variation of a regenerated data clock and of the associated data packet has a first-in/first-out (FIFO) buffer to which an input clock associated with the data packet and data from the data packet are input. A sample clock derived from a regenerated data clock is used to clock the data out of the FIFO buffer, the regenerated data clock being a function of a reference frequency signal and a period control parameter. The regenerated data clock and input clock are compared to determine a buffer occupancy for the FIFO buffer, from which the period control parameter is derived. From the period control parameter and the buffer occupancy delay variation of the regenerated data clock and of the associated data packet is calculated.

Abstract: A real-time wavelength calibration scheme for a swept laser generates an electrical signal from a swept optical output of the swept laser that is cyclical with respect to the wavelength of the swept optical output over a defined range of wavelengths. The point on the electrical signal at any given time provides an accurate phase for the swept optical output at that point. The electrical signal in turn is calibrated by generating calibration references from the swept optical output using known absorption lines within the defined range of interest. The wavelength of the swept laser is calibrated as a function of a reference wavelength from the known absorption lines and the phase at the given point.

Abstract: Multiple views of the signal are generated by a time-sharing use of the oscilloscope's acquisition hardware. The instrument software makes a set of measurements of the input signal, and from the results of those measurements classifies the input signal as to type. Signals of particular types implicitly select suites of views of the signal. The operator sees examples of the other views available while a related view is the main view. Alternate views can be “live” miniature views, and displayed alongside in simplified form, alongside the main view. By clicking on them, these alternative views may be made to become the main view. The operator can add and modify views. Each view comes with a set of measurements that are automatically performed and the results are displayed on the screen as text annotation to the waveform. A different view of the signal comes with different automatic measurements, and presents the results of these measurements as annotations to the waveform image.

Abstract: A method for reducing noise in a four-quadrant multiplier having first and second cross-coupled pairs of differential bipolar transistors, differential input current terminals connected with a first pair of common junctions of the respective pairs of differential transistors and the differential output current terminals cross coupled to form a second pair of common junctions of the respective pairs of differential transistors is described. The method includes providing a noise current path from the differential input current terminals to a bias voltage, the noise current path substantially bypassing the differential output current terminals when the gain of the multiplier is near zero.

Abstract: A method of automatic testing of systems, such as DWDM systems with an OSA, has manufacturer's specifications loaded into the test equipment for a plurality of systems. A user selects one of the systems from a menu, and the test equipment from the manufacturer's specification for the selected system automatically acquires data and makes measurements on the data. The results of the data are summarized in a report which indicates an overall system status, indicating where and why the system failed if any of the measurements indicates the system is out of the manufacturer's specifications. The measurements are kept so that they may be used to determine drift when the system is tested the next time.

Abstract: A low capacitance probe tip and socket for a measurement probe has a probe tip extending through an insulating plug and a recess defining a socket formed in the plug. The socket has an aperture formed therein that provides access the low capacitance probe tip. An electrically conductive contact is disposed in the aperture that extends into the socket and is in electrical contact with the low capacitance probe tip. In one embodiment, the socket is formed parallel to the low capacitance probe tip. In a further embodiment, the socket is formed at an angle to the low capacitance probe tip with the electrically conductive contact being an electrically conductive elastomeric material disposed at the distal end of the socket in electrical contact with the low capacitance probe tip.

Abstract: The time stamping method for an input signal generates time marked digital data values as a reference edge and defines at least a first time stamp in the reference edge. Digital data samples of the input signal are acquired to create a waveform record of the input signal. The digital data samples of a waveform record edge are compared to time equivalent digital data values of the reference edge to generate a error value representative of the difference between the waveform record edge and the reference edge. A time offset value is generated from the error value to vary the time location of the reference edge and the comparison and time offset generating steps are repeated to minimize the error value. The time offset value at the minimum error value is combined with a time location of nearest digital data sample of the waveform record edge to generate a waveform record edge time stamp.

Abstract: A facility for mounting an electronic component includes a first circuit board having of mounting apertures. A mounting element is associate with each aperture, and includes a boss defining a bore. The boss has a first surface contacting a major surface of the first circuit board, and a second surface opposite the first surface. A pin is received in the bore, and has a lower portion protruding from the first surface of the boss and into one of the apertures. The pins lower portion definves a spece to capture a portion of the first circuit board. A fastener connected to the pin may generate compression between the spece and the boss to secure the board, and a corner-shaped protrusion on the second surface may constrain the corner periphery of a second board resting on the second surface, with the fastener also securing the second board against the boss.

Abstract: A rear-mount integrated rotary encoder comprises a mechanical portion and a printed circuit board portion. The mechanical portion of a rear mount integrated rotary encoder comprises a housing including a bushing for receiving one end of a rotatable. The rotatable shaft passes through an open front portion of the housing and is mechanically connected to exposed rotatable circuit contacting members. The printed circuit board portion has an encoder contact pattern formed thereon. The printed circuit board has an area larger than the cross sectional area of the housing. The encoder contact pattern surrounds an aperture in the circuit board. The rotatable shaft of the rotary encoder is passed through the aperture such that the rotatable circuit contacting members contact the encoder contact pattern on the circuit board. The housing includes projections, substantially orthogonal to the circuit board, for engaging a feature of the circuit board for securing the integrated encoder in an assembled state.

Abstract: A method of interference cancellation in antenna test measurements is achieved by acquiring an acquisition at a test port of an antenna test instrument in response to an internal signal source, stamping the data acquisition time, and measuring a signal vector that has both a reflection signal component and an interference signal component. Another acquisition at the test port without the internal signal source is obtained with limited data points to detect whether there are interference signals. If there is significant interference power, a complete acquisition is obtained without the internal signal source, the data acquisition time is stamped, and an interference vector that has only the interference signal is measured.

Abstract: Overload distortion protection for a wideband receiver having a wideband variable gain input amplifier followed by a frequency conversion stage followed in turn by an intermediate frequency amplifier and detector to produce a measurement value in response to a signal input to the wideband variable gain input amplifier is achieved by detecting the peak power of the signal at the output of the wideband variable gain input amplifier and comparing it with the power output from the intermediate frequency amplifier and detector. If a threshold difference is exceeded, gain control signals for the wideband variable gain input and intermediate frequency amplifiers are adjusted for optimum dynamic range. If there is no range for adjusting the gain control signals, then a warning is provided to an operator to alert that the measurement value may contain distortion.

Abstract: A system for determining the phase and magnitude of an incident signal relative to a cyclical reference signal, includes a sampler for sampling the incident signal. Autoranging circuitry is responsive to the reference signal and determines the frequency f of the reference signal and sets the sampling rate sr of the sampler. A processor, responsive to the sampler, computes a single point DFT v of the sampled incident signal responsive to the frequency of the reference signal and determines the phase &thgr; and magnitude |v| of the incident signal relative to the reference signal in response to the single point DFT.

Abstract: A frequency domain measurement device multi-phase modulates an RF frequency signal with a broadband signal, such as a pseudo random number, to produce an RF spread spectrum signal that encompasses a frequency range of interest. The RF spread spectrum signal is transmitted to a device under test, and a corresponding reflected signal from the device under test is correlated with the RF spread spectrum signal to produce information from which location of and distance to a fault in the device under test may be determined. A FIR filter is used as part of the correlation process to determine magnitude and phase versus frequency over the frequency range of interest for the device under test as well as location of and distance to the fault.

Abstract: A method of operating an oscilloscope includes acquiring waveform data using a group of default acquisition parameters, analyzing the acquired waveform data in accordance with a selected one of several rule sets and deriving an optimized group of acquisition parameters. The method then proceeds by acquiring waveform data using the optimized group of acquisition parameters, and displaying the waveform data acquired using the optimized group of acquisition parameters.

Abstract: A method of calibrating a timebase in a digitizing instrument estimates the frequency of the clock signal from the clock generator that clocks a coarse delay counter in a strobe generator. The dynamic range of the interpolator in the strobe generator is defined in digital-to-analog converter code values as a function of the clock signal period. A linear horizontal look-up table of equally spaced digital-to-analog converter code values is generated over the defined dynamic range of the interpolator. Residual nonlinearities of the interpolator over the defined dynamic range of the interpolator are characterized and scaled to digital-to-analog converter code values. The digital-to-analog converter code values of the characterized residual anomalies are combined with the digital-to-analog converter code values of the linear horizontal look-up table to generate a horizontal look-up table having DAC code value compensating for the nonlinearities of the interpolator.

Abstract: A portable general-purpose oscilloscope employs circuitry for receiving and converting serial digital video signals to composite and component analog signals via a digital to analog converter. The converted analog signals are applied to signal inputs of the oscilloscope for monitoring and display. Preferably, the oscilloscope is a digital phosphor oscilloscope. The oscilloscope control menus are arranged to control all of the usual functions of the oscilloscope and also to control the serial digital video circuitry. Apparatus is provided for storing data and waveforms. Circuitry is disclosed for deriving a trigger signal from a specific digital word of the serial digital bit stream. The trigger signal is applied to the trigger input terminal of the oscilloscope to allow the oscilloscope capture and display television waveform information around a unique occurrence of an event, as specified by the digital word.