Abstract: A receiver processor for use in a SONET OC-48 or SDH test or network environment. The processor includes a 16:32 demultiplexer, descrambler, and a cross-connect enabling individual STS-3s in the incoming signal to be routed to selected STS-3s in the outgoing signal. An overhead and data capture function enables overhead and data bytes to be captured from each frame.

Abstract: An electrical connector with a female portion defining a bore having an aperture, and a male portion having an elongated member sized to be received in the bore. The female portion has a first flexible contact and an electrically isolated second rigid contact. The male portion has a first flexible contact and an electrically isolated second rigid contact. The connector may be a banana connector with a barrel spring providing conventional contact, and a separate contact at the tip of the male portion.

Abstract: An adapter for a measurement test instrument electrical probe has a flexible dielectric substrate with electrically conductive runs thereon. One end of the conductive runs has first electrical contacts with a pitch geometry corresponding to the pitch geormetry of electrical contacts of an electronic device that is electically connected to a substrate via the electrical contacts of the device. The other end of the conductive runs has second electrical contacts that have a pitch geometry compatible with the electrical probe of the measurement test instrument.

Abstract: An automatic output offset control circuit for a DC-coupled RF amplified optical-to-electrical converter has a photodiode for converting an optical signal to an electrical signal. The current from one side of the photodiode is coupled into the input of a bipolar RF amplifier that generates a voltage output. The current from the other side of the photodiode is sensed for generating a voltage that is compared with the output of the RF amplifier. Any mismatch between the sensed current and the RF amplifier generates an error signal that is used to control the DC bias supplies of the RF amplifier. The DC bias supplies are adjusted in unison to produce the correct offset at the amplifier output for the given photodiode current while maintaining a constant AC-gain. The circuit automatically corrects for the DC-coupled output offset drift and variations of the RF bipolar amplifier. The circuit may be implemented using either voltage or current signals to the feedback circuit.

Abstract: An apparatus and method are described for applying an intermediate transfer surface, in the form of a liquid layer, on a support surface as may be used in a phase change ink printing system. The apparatus includes an applicator assembly for distributing the liquid layer onto the support surface to produce the intermediate transfer surface and an apparatus for metering the liquid layer uniformly on the support surface. The applicator assembly has a contact medium for removing foreign matter from and delivering the liquid onto the support surface. Preferably the contact medium is a liquid impregnated web that is periodically incremented to present a clean web surface in contact with the support surface. The metering apparatus is a hydrodynamic blade that uniformly distributes the liquid intermediate transfer layer over the support surface.

Abstract: An electrical signal jitter and wander measurement system (30) operates in real time and digitally controls bandwidths over which the measurements are performed. A digital phase-lock loop ("PLL") (34) includes a phase detector (44), low pass filters (48, 56), an analog-to-digital converter ("ADC") (54), a digital signal processor ("DSP") (32), a direct digital synthesizer ("DDS") (38), and a tracking oscillator (39). The phase detector receives an input signal that is compared with a signal derived from the DDS. The phase detector signal contains wander and jitter data that are filtered and digitized by the ADC. The DSP receives the data and performs a proportional integral control function to lock the PLL by digitally controlling the DDS frequency. The DDS generates a clock signal at a precise rate determined by the phase accumulation registers. The tracking oscillator locks to multiples of the DDS frequency to increase the resolution of the phase measurement.

Abstract: A phase measurement apparatus and method for measuring electrical signal jitter and wander operates in real time and digitally controls bandwidths over which the measurements are performed. The apparatus includes a digital phase-lock loop (PLL) for generating phase difference signal data having first and second frequency components above and below the loop bandwidth of the phase locked loop. An analog-to-digital converter digitizes the analog phase difference signal from the phase detector. A digital signal processor (DSP) receives the digital data and performs a loop filter function for generating frequency update values to the DDS for phase locking the PLL to an incoming signal. The DSP performs an integration function on the loop filter function output to generate the second frequency components. The first and second frequency components are combined in a summing circuit and filtered in digitally programmable low and high pass filters for establishing measurement bands for measuring the phase difference.

Abstract: A signal generator has a variable reference oscillator, a variable oscillator and a phase locked loop for generating an output having jitter and wander. The variable reference oscillator generates a reference having a varying phase offset over a first phase modulation frequency interval and a constant output over a second phase modulation frequency interval. The variable oscillator generates a constant output over the first phase modulation frequency interval and a variable output over the second phase modulation frequency interval. The phase locked loop includes a phase detector, a phase summing node and oscillator with the phase detector coupled to receive the outputs of the variable reference oscillator and the oscillator, and phase summing node coupled to receive the outputs of the variable oscillator and the phase detector.

Abstract: A multimode optical time domain reflectometer has first and second wavelength optical transmitters for launching optical pulses into a fiber under test and optical receivers responsive to the respective wavelengths for converting the optical return signals from the test filer into electrical signals for acquiring waveform data representative of the optical return signals at the respective wavelengths. A processor receives the waveform data and determines a difference in fiber slopes between the optical return signal at the respective wavelengths and adds the fiber slope difference to the waveform data of the second optical return signal for producing composite waveform data having a uniform fiber slope for the waveform data acquired at the first and second wavelengths. A multimode optical time domain reflectometer of this design provides improved two point resolution for 1310 nm testing of multimode optical fiber.

Abstract: A current probe (10) measures a signal current flowing in a conductor (12), which produces a signal flux (14) proportional to the signal current. The probe includes a pair of probe arms (16, 18) that straddle the conductor, a flux shunt (20), a pair of flux diverting arms (22, 24), and a flux link (26). A Hall-effect device (28) senses the amount of flux flowing in the flux shunt. A major portion of the signal flux flows in a preferential path (30) through the flux shunt while a minor portion flows in a flux diverting path (32). The ratio of the amount of the signal flux flowing in the preferential flux path to the diverting path depends on the reluctance in each path, which is determined by air gaps (27, 34). The Hall-effect device drives a current source (40) that provides a diverter current through a pair of flux diverting coils (42, 44) that are wound around flux diverting arms (22, 24) of the current probe.

Abstract: An remote fiber test system includes a non-blocking N.times.N optical switch having N input ports and N output ports with one of the input ports coupled to a measurement test instrument for examining any of the optical fibers coupled to the output ports. The non-blocking switch includes a plurality of N input mechanical optical switches and an plurality of N output mechanical optical switches with each of the input mechanical optical switches having an input optical transmission path representing one of the input ports and each of the output mechanical optical switches having an output optical transmission path representing one of the output ports. Each input mechanical optical switch has N output optical transmission paths which each optical transmission path being coupled to one of the input optical transmission paths of each of the output mechanical optical switches.

Abstract: An remote fiber test system includes at least one mechanical optical switch has opposing input and output optical fiber bundles disposed within offset ferrules with at least one input fiber coupled to a measurement test instrument and each of the output fiber coupled to an optical fiber link via wavelength division multiplexers. Each ferrule of the optical switch is mounted in three-point kinematically correct V-groove holder allowing the optical fibers in each optical fiber bundle to traverse on a closed curve path during the rotation of the respective ferrules. The closed curve paths of each optical fiber in one of the optical fiber bundles intersect at least one of the closed curve paths of the optical fiber in the opposing optical fiber bundles. The intersection points of two opposing closed curve paths establish the optimum positioning locations for two opposing fibers.

Abstract: A mechanical optical switch having opposing first and second optical transmission paths, such as optical fibers, forming an optical interface and rotating about respective independent and offset first and second rotational axes for positioning the fibers on respective first and second offset and intersecting closed curves operates to rotate the input or first optical fiber on its closed curve to one of the two intersecting points on its closed curve in response to the angular coordinate representative of the position of fiber at the intersecting point matching the intersecting point of the second optical fiber. The output or second optical fiber is rotated on its closed curve to the intersecting point corresponding to the intersecting point of the first fiber in response to the angular coordinate representative of the position of the second fiber at the intersecting point. These rotational movements may be performed sequentially, but in the preferred embodiment they are performed simultaneously.

Abstract: The angular coordinates representative of intersecting points on closed curves of a first optical fiber axially offset from a plurality of optical fibers in a mechanical optical switch are determined by imaging respective end faces of opposing first and second mounting members containing the respective fibers for determining the locations of the optical fibers in the mounting members and at least one reference point within one of the mounting members. The relative angular coordinates of the intersecting points between each of the closed curves of the plurality of optical fibers and the closed curve of the first optical fiber are aligned as a function of aligning the first optical fiber with the reference point. One of the plurality of optical fibers is optimally aligned with the first optical fiber at one of the intersecting points on the closed curves using the adjusted relative angular coordinates as the starting angular coordinates.