Abstract: An optical spectrum analyzer involves a swept local oscillator signal that is depolarized before the swept local oscillator signal is combined with an input signal. An embodiment of a system for optical spectrum analysis includes a depolarizer, an optical coupler, and a heterodyne receiver. The depolarizer has an input to receive a swept local oscillator signal and an output for outputting a depolarized swept local oscillator signal. The optical coupler has a first input and a second input, the first input receiving an input signal, the second input being optically connected to the depolarizer to receive the depolarized swept local oscillator signal. The optical coupler also has an output for outputting a combined optical signal that includes the input signal and the depolarized swept local oscillator signal. The heterodyne receiver has an input for receiving the combined optical signal from the optical coupler and an output for outputting an electrical signal representative of the combined optical signal.

Abstract: For measuring a polarization dependent parameter of an optical device under test—DUT—, an optical source provides an optical stimulus signal at variable wavelengths, and a polarization translator translates the polarization state of the optical stimulus signal applied from the optical source at its input to its output in a deterministic way dependent on the wavelength of the optical stimulus signal. A receiving unit receives an optical response signal from the DUT to the applied optical stimulus signal, and an analyzing unit analyzes received optical response signals for different wavelengths for determining values of the polarization dependent parameter of the DUT.

Abstract: A protocol analyzer for a test system has a control system coupled to a first interface and a second interface. The first interface receives a packet from a packet network. The control system receives the packet from the first interface and either deletes the packet or transfers the packet to the second interface based on a destination address in the packet. The second interface transfers the packet to another protocol analyzer. The destination address could be a MAC address.

Abstract: An apparatus for calibrating the DC voltage level of measurement equipment supplies a calibration voltage through a DC voltage superposition means to the measurement equipment, detects the voltage level supplied to the measurement equipment, and adjusts the calibration voltage. Therefore, in the high-frequency range, the calibration apparatus can reduce the effect on the measurement accuracy of the measurement equipment and supply a highly accurate calibration voltage to the measurement equipment.

Abstract: An integrated circuit device includes a two-dimensional array of ferroelectric memory cells in which plate lines within the array are grouped. The grouping of plate lines accommodates the use of larger plate line drivers, such as CMOS driver inverters. Each plate line group may include some but not all of the rows of memory cells and some but not all of the columns of memory cells within the array.

Abstract: An optical switching apparatus and a method of efficiently switching optical signals are disclosed. Optical insertion loss may be reduced in a planar lightwave circuit by determining an optimal spacing between perturbations including using passive perturbations, having a three dimensional refractive index distribution, in an array of waveguides, or by adjusting parameters of existing perturbations e.g. their spacing. The perturbation and each waveguide have different three dimensional refractive index distributions. The perturbation may be positioned anywhere in the array of waveguides. The perturbation may be a trench, a region of refractive index different from that in each waveguide, a broken waveguide core, or a modification of the topography of the array of waveguides. In one embodiment, the perturbation is a periodic or quasiperiodic perturbation.

Abstract: The present invention is directed to a method and apparatus for balancing forces in a fixture and reducing forces in a probe plate (208) housed in the fixture. A plurality of double-ended probes (200) are positioned in the probe plate (208). A first bit (216), located at one of the double-ended probe (200) is in contact with a board under test (206). A second bit (218), which is oppositely disposed and located on the other end of the double-ended probe (200) is in contact with a wireless PCB (202). A spring (220) runs the length of the double-ended probe (200) and is in contact with the first bit (216) and the second bit (218).

Abstract: A connector assembly includes a first connector half, and a second. The first connector half includes a first transmission line, having a first outer conductor and a first center conductor. The first center conductor has a first end that has an angled flat region. The second connector half, includes a second transmission line. The second transmission line includes a second outer conductor and a second center conductor. The second center conductor has a first end that has an angled flat region. When the first connector half and the second connector half are connected together, the first outer conductor is electrically connected to the second outer conductor. Additionally, a wiping contact is established between the angled flat region of the first end of the first center conductor and the angled flat region of the first end of the second center conductor.

Abstract: An eye diagram analyzer can assign a plurality of SUT data signals to be members of a labeled group of channels. There may be a plurality of such groups. The measured data for components within a group can be merged according to various different modes into a composite eye diagram presentation. When a composite eye diagram is being displayed, the operator may position a screen pointer (cursor) over some interesting part of the eye diagram, and the analyzer will display a list those channels that contributed to the displayed pixels in that part of the eye diagram, as well as other related information. The operator may also select a channel from among the group, and then have the displayed pixels for which it is responsible be displayed in a selected color or otherwise highlighted in a way that allows them to be distinguished from all others.

Abstract: The present invention is related to a method for positioning fingers of a spread spectrum rake receiver, comprising the steps of:

Abstract: The present invention is related to a rake receiver for searching, tracking and combining multipath signals in a spread spectrum transmission, characterised in that it further comprises a plurality of generic fingers (11) arranged to perform any of functions selected from the group consisting of searching, tracking and combining a multipath signal.

Abstract: A control loop detects the presence of cross-talk between first, second and third adjacent amplitude modulated wavelength division modulated channels of an optical communications system. A receiver including a demultiplexer, such as an Arrayed Waveguide Grating (AWG), receives portions of the energy in the channels to derive first, second and third electrical signals that are respectively replicas of the modulation of the first, second and third channels. Wavelength drift of the carried frequencies of the channels in detected by comparing the three signals in an electronic combinatorial logic unit.

Abstract: An avalanche photodiode having an operating voltage greater than a DC power supply rail is connected to the rail via a controlled DC-DC converter having an output voltage that drives the photodiode and meets the photodiode voltage supply needs. A measure of the current flowing from the rail to the converter determines the value of a control signal for the converter output voltage. The photodiode current is computed from the current measure and the control signal value.

Abstract: A novel method and apparatus is presented for reducing the slew rate signals on transmission lines of integrated circuits by stepwise ramping up or down the voltage level on the transmission line. Switched capacitors or current sources are connected to either directly to the transmission line itself, or to the control input of a driver device characterized by a linear region during which the output voltage on the transmission line is proportional to the voltage seen at the control input.

Abstract: Intelligent logic activity resolution (ILAR) is provided for a process. Upon a first trigger event being received, a first subset of conditions of the process is detected. The first subset of conditions is selected based on the first trigger event. When the first subset of conditions match predetermined values, a first state is entered. When the first subset conditions do not match the predetermined values, additional conditions are checked. On the basis of the checked additional conditions, a new state is selected for entry.

Abstract: A self calibrating register. In representative embodiments, registers for increasing source synchronous input/output (I/O) data rates by counteracting the inherent systematic sources of system mismatch are disclosed. Systematic sources of system mismatch between bit-line paths and devices, as for example printed circuit board path lengths, package trace lengths, on-chip clock routing, clock skew, device turn-on voltages, etc. are balanced out with respect to a reference clock signal by programmed delays of the data signals. The appropriate delays are obtained via phase shift detection circuitry and are then applied by control circuitry to signal delay circuitry.

Abstract: A spectral characterization method accurately characterizes an applied signal spectrum that has multiple, spectrally-separated signal peaks. The method detects signal peaks within the spectrum and measures the spectral content of that spectrum using a first measurement bandwidth that is sufficiently wide to encompass each of the signal peaks and accurately measure a signal component of the spectrum. Spectral content of the spectrum measured using a narrow measurement bandwidth that accurately characterizes a noise component of the spectrum. Signal-to-noise ratio for the signal peaks can be calculated based on the measurements performed using the first and second measurement bandwidths. The spectral characterization method is implemented using a spectral measurement instrument having an adjustable measurement bandwidth.

Abstract: A dual mode amplifier having single ended and differential ended modes of operation using only one set of output pads or terminals. The dual mode amplifier has two differential amplifiers, connected by coupling circuitry, each differential amplifier receiving a pair of differential input signals and having one output terminal. By activating and deactivating the coupling circuitry, the differential amplifiers can operate in two modes using the one set of output terminals. In the singled ended mode, the differential amplifiers operate independently, each converting the differential input signals to a singled ended output signal at their respective output terminals. In the differential mode, the differential amplifiers operate together to provide a pair of differential output signals at the output terminals based upon the pair of input signals.

Abstract: An improved circuit board inspection system incorporates self learning techniques for accurate determination of Z-axis elevations of electrical connections. A Delta Z, referenced to a laser range finder generated surface map of the circuit board, is automatically determined from a series of cross sectional images of the electrical connections for each electrical connection on the circuit board. The Delta Z values for each electrical connection are stored in a data base from which customized Delta Z values for specifically defined board views may be calculated.

Abstract: A circuit board coupon testing method and apparatus. A coupon tester uses a linear actuator to carry a test head and probe(s) for an LCR meter. The linear actuator accurately steps the probe(s) over a coupon of components arranged linearly adjacent an edge of the circuit board to measure the parameters of the component. The coupon tester can be integrated with an in-circuit tester to provide further functionality, with the coupon test being carried out simultaneously with a portion of the in-circuit test such as an unpowered portion of the in-circuit test.