Abstract: A low capacitance probe tip, having minimal metal content to reduce loading on a circuit under test, is formed from a small diameter wire. The small diameter wire had a straight section, a formed section and a pointed front end section. The major dimension of the formed section is slightly greater than the interior diameter of a small diameter hole in a probe body so that, when inserted into the small diameter hole, the formed section forms an interference fit with the hole to securely hold the probe tip in the probe body. The probe tip within the hole makes electrical contact with a hybrid electrical circuit board having an electrical contact at the small diameter hole. The formed section shrinks when pulled for either insertion or replacement, and expands to form the interference fit when the pulling tension is removed. Thus the probe tip is readily replaceable.

Abstract: A pixel processor converts data indicating origin, direction, length and intensity of each of a set of lines forming a picture into a half tone bit map on the picture. The pixel processor organizes the picture into an array of similar half tone cells, each half tone cell being a rectangular array of pixels, by storing adjustable data indicating the size of a half tone cell and a pixel intensity threshold level for each pixel of a half tone cell. When processing each line, the pixel processor reads pixel data words out of the bit map, each pixel data word including at least one bit corresponding to a pixel along the path of the line. For each such bit, the pixel processor determines the half tone cell position of the corresponding pixel, determines whether the pixel intensity threshold level assigned to that half tone cell position is lower than the intensity level of the line and sets the state of the bit accordingly.

Abstract: A polarization insensitive optical attenuator (10,40) uses a polymer-dispersed liquid crystal (PDLC) film (14,56) to provide attenuation control over a wide range of attenuation values. The attenuator has a relatively low minimum attenuation and reliable light transmission with minimal insertion loss. The present invention is also adaptable for use with a temperature controller (200) that stabilizes the PDLC film, which promotes more uniform, predictable attenuation values.

Abstract: A high density probe for probing an integrated circuit package in situ on a circuit board has a probe body with a skirt that has alignment surfaces for mating with the package to provide an initial alignment. An alignment plate is elastically mounted within the probe housing internal of the skirt. The alignment plate has serrations between pin holes, the pin holes corresponding to probe pins elastically mounted on the probe housing in a pattern matching the leads of the integrated circuit package. When the probe is pressed down over the integrated circuit package the alignment surfaces within the skirt align the probe to the package, and the serrations mesh with the leads to align the probe pins with the leads, the probe pins extending through the pin holes and maintaining positive contact due to the elastic mounting of the pins.

Abstract: An optical time domain testing instrument comprises a laser light source that is optically coupled to an optical fiber under test. The instrument further comprises a photodetector for receiving light from the fiber, and an optical amplifier optically coupled between the fiber and the photodetector.

Abstract: A serial-to-parallel analog CCD GaAs device provides high speed A/D or D/A conversion. A high speed analog signal is sampled by shifting the analog data serially into "n" CCD elements. Then a parallel load pulse transfers the analog data into multiple CCD holding elements. A bank of A/D converters converts the analog data. Conversely, the outputs of a bank of D/A converters are loaded in parallel into a serial CCD device of "n" elements. The serial CCD device is shifted out serially to complete the conversion to an analog signal.

Abstract: An ultra-short optical pulse source uses a gain-switched laser diode with a dispersive delay line to compress the optical pulse output from the laser diode, the gain-switched laser diode having particular spectral characteristics. The gain-switched laser diode may be tested by energizing it with a continuous wave signal at or near the lasing threshold level. The resulting spectrum is examined for the presence of satellite spectral intensity features. Those gain-switched laser diodes that exhibit a spectrum having all satellite spectral features below a predetermined level with respect to the intensity of a principal spectral component are selected for use in the ultra-short optical pulse source.

Abstract: A logarithmic amplifier includes a first diode wherein the anode receives an input signal input signal current and a standing current. The cathode of the first diode is coupled to the emitter of a PNP transistor. The collector of the PNP transistor is coupled to the anode of a second diode. A bias current is added to the emitter and substracted from the collector of the PNP transistor to provide a lower emitter impedance. The cathode of the second diode is coupled to a negative supply voltage through a load resistor. A feedback network including an emitter coupled pair of NPN transistors samples the voltage at the anode of the second diode and sinks a current from the base of the PNP transistor. The voltage at the anode of the first diode is amplified to provide a logarithmic output voltage. The output voltage may be attenuated and applied to the base of the PNP transistor.

Abstract: A method of measuring timebase jitter for component video compares a test signal from a reference signal generator, such as a bowtie signal or a fixed carrier frequency signal, with the same test signal from a local phase locked signal generator for which timing jitter is to be determined. The test signals are timed to be coincident by adjusting appropriate delay lines and timing controls. For a bowtie signal the width of an indeterminate region for the intersection of the bowtie signal is a measure of the timebase jitter, the value of which is determined using the cursors provided by the bowtie signal. For a fixed carrier frequency signal the respective test signals are equalized in amplitude and timed for coincidence, and then modulated together. The modulated signal is lowpass filtered and processed by a fast Fourier transform to provide a display of the timebase jitter.

Abstract: A high resolution optical fault locator for single mode applications uses a high power, short wavelength laser for generating narrow optical pulses that are launched into a single mode fiber under test. The laser output is coupled to a multimode coupler whose output is coupled to a multimode output fiber. The multimode output fiber is fusion spliced with a single mode fiber, which is coupled to a front panel connector for connecting the fiber under test to the fault locator. An optical detector that is compatible with the output laser is coupled to the multimode coupler to receive the reflected light from the fiber under test. The high resolution fault locator is useful in examining single mode local area networks where many closely spaced fiber connections exist.

Abstract: A video signal in component form is processed by generating two chroma component signals which have a selected bandwidth and are GAMMA corrected, generating a linear luminance component signal which has a greater bandwidth than the chroma component signals and is not GAMMA corrected, and GAMMA correcting the linear luminance component signal to provide a GAMMA-corrected luminance component signal having a greater bandwidth than the GAMMA-corrected chroma component signals.

Abstract: Adjustable electronic graticules for measuring waveform distortions are generated from operator inputs indicating a measurement mode and a scale factor. A template of a graticule for the measurement mode in the form of a display list of move and draw instructions is scaled by the scale factor and a measurement value is computed from the scale factor and the instrument units per division setup. The graticule and measurement value are stored as a modified display list. A readout engine interprets the modified display list and produces electrical signals for drawing the graticule and measurement value on a display monitor. The electrical signals are combined with the waveform for display on the display monitor. The operator varies the scale factor until the displayed graticule touches the waveform at a measurement point, and the measurement value is accordingly displayed.

Abstract: A phase-selectable flip-flop has an input dual-enable transparent latch and an output D-type flip-flop. A clock is input to one enable of the transparent latch and to the flip-flop, and a command is input to the second enable of the transparent latch. When the command is in a first state the latch is held transparent and data is clocked into the flip-flop on the rising edge of the clock, and when the command is in a second state data is held by the transparent latch on the falling edge of the clock and clocked into the flip-flop on the succeeding rising edge.

Abstract: An oscilloscope includes a digitizing camera mounted thereon for recording waveforms on the oscilloscope screen. The digitized signals representing the waveforms are stored in the computer. In the calibration process a plurality of baselines substantially equidistant from one another are scanned on the screen and thereafter a plurality of sine waves are scanned. The phase differences between each sine wave and an associated ideal sine wave are determined and are used to create a map which associates each point on a waveform of interest appearing on the oscillosope screen with a time value that corrects for nonlinearities in the horizontal axis which are injected by the optics, nonlinear voltages, etc. Another map is created utilizing the baseline scan which corrects for such nonlinearities in the vertical axis.

Abstract: A television signal generator which is fully digital has digital data stored in PROMs, one PROM for each component of the desired encoded television signal corresponding to luminance data and chrominance data. A system clock allows a signal address generator to fetch data from the PROMs. The chrominance data from the PROMs is mixed with appropriate digital representations of a sinusoidal function and a phase offset and is added to the luminance data. The combined digital signal is converted to analog, filtered and output as the desired encoded television signal.

Abstract: A nonvolatile memory protection system for a microprocessor system having a common address bus, to which a nonvolatile memory is connected, interposes a controller connected to the common address bus between the commands generated by the microprocessor and the nonvolatile memory. The controller generates valid commands for the nonvolatile memory upon receiving a predetermined sequence of commands from the microprocessor, disabling the nonvolatile memory in the absence of valid commands. A power protect circuit connected between the microprocessor system power supply and the nonvolatile memory provides a disable signal to the nonvolatile memory during power up and power down of the microprocessor system.

Abstract: A video signal in component form is processed by generating two chroma component signals which have a selected bandwidth and are GAMMA corrected, generating a linear luminance component signal which has a greater bandwidth than the chroma component signals and is not GAMMA corrected, and GAMMA correcting the linear luminance component signal to provide a GAMMA-corrected luminance component signal having a greater bandwidth than the GAMMA-corrected chroma component signals.

Abstract: An electro-optical transducer module comprises a substrate having a planar main surface, an electro-optical transducer adhered directly to the main surface of the substrate, and an optical fiber adhered directly to the main surface of the substrate. The optical fiber has an end face in optically coupled relationship with the transducer. A handling element is adhered to the fiber, the fiber being between the handling element and the main surface of the substrate.

Abstract: A method of displaying acquired data where a full screen base line display is scaled to represent the total duration of a device under test. Acquired data points are positioned on the base line display at locations proportional to their time of occurrence in the test. Icons, symbolic of the type of event associated with the acquired data points, are shown on the base line display. A movable bifurcating cursor points to the events and associated alphanumeric displays give distance and type of event information.

Abstract: An apparatus for connecting an integrated circuit, IC, device to a test system has a first circuit board on which the IC device is mounted. The circuit board has an analog transmission line interposed between and electrically isolated from digital transmission lines on opposed surfaces of the circuit board. The first circuit board is electrically connected to a second circuit board via coaxial probe assemblies disposed within apertures formed in a frame member mounted on the second circuit board. Each coaxial probe assembly has a connector disposed within one end of the aperture and a coaxial probe disposed with the other end. The connector and the probe head each have a cylindrical outer conductor electrically isolated from a central conductor. The cylindrical conductor and the central conductor of the connector are electrically connected to conductive runs on the second circuit board.