Abstract: An SWR bridge with an accompanying set of connector saving adapters for connecting between the test port of the SWR bridge and a test device. The SWR bridge includes a branch opposite the test port which has an impedance set to substantially compensate for the impedance of the connector saving adapters. The connector saving adapters are configured to mate with connectors from two groups of test device connectors in both male and female versions, a first group including 3.5 mm, SMA and 2.92 mm connectors, and a second group including 2.5 mm and 1.85 mm connectors. To compensate for any capacitive mismatch between an adapter configured for a particular group of connectors and a given connector type, either a center conductor pin setback, an inductive counter bore in the outer conductor of the adapter, or a combination of the center pin setback and inductive counter bore may be utilized.

Abstract: A variable termination load switch (102) is provided to enable transmission and group delay measurements to be made of a device under test (DUT) (103) using only one port of a vector network analyzer (VNA) (100). The variable termination load switch (102) selectively provides an open or a short based upon a signal provided to its control input (106). The variable termination load switch (102) has a load port (113) for connecting to one port of the DUT and the VNA port is connected to another port of the DUT during testing. The variable termination load switch (102) includes a diode (143) connected by a resistor (149) to the control input (106). The diode (143) has connected parallel transistors (141, 142) and a series transistor (140) to provide a load impedance matching the DUT impedance when the load is functioning either as a short or an open. Isolation capacitors (145) and (146) reduce the affect of AC signals from the control input (106).

Abstract: A radar test system for testing a collision avoidance radar system. The radar test system includes circuitry to downconvert a signal from the collision avoidance radar to an intermediate frequency signal, to delay the intermediate frequency signal to simulate the delay of a return signal from an object located a particular distance from the collision avoidance radar system, and to upconvert and transmit the intermediate frequency signal back to the collision avoidance radar system to determine if the collision avoidance radar system provides accurate distance readings. The radar test system further couples the intermediate frequency signal to a spectrum analyzer. The spectrum analyzer can be used to determine if the collision avoidance radar system is operating within the 76-77 GHz frequency band allocated by the Federal Communications Commission (FCC). The radar test system further couples the intermediate frequency signal to a power meter.

Abstract: A metallic access test extension system architecture for a digital transmission system is provided. The digital transmission system includes a local end and a plurality of remote ends, each of said plurality of remote ends including a digital communication path and a metallic test pair connection. The local end includes a corresponding digital communication path and corresponding metallic pair connection. The architecture includes a remote unit coupled to each metallic test pair and digital communication path at each of said plurality of remote ends. The remote unit includes a metallic access test extension module. The architecture further includes a central office unit at the local end of the digital communication path, the local end unit including a metallic test extension module and a switch system, responsive to a control signal, for selectively connecting the digital communication paths and metallic test pairs at the local and to the metallic test extension module in the local end unit.

Abstract: A graph of data samples in a graph field on the display, including a first coordinate axis, a second coordinate axis, a trace indicating characteristics of data samples with respect to the coordinate axes, and a plurality of markers indicating positions of respective data samples along the trace is displayed. The markers appear on the display in the form of a symbol and a marker annotation field and are positioned within the graph field adjacent the data sample to which they are tied. The positions of the marker fields of the plurality of markers are calculated according to a preferred orientation with respect to the trace and their respective data samples. Markers are identified for which the marker annotation field according to the calculated position, lie in whole or in part outside the graph field, or for which the marker annotation field overlaps a marker field of another marker in the plurality of markers.

Abstract: A device for measuring and/or injecting a high frequency signal, such as a 20 GHz signal from and/or into a system, is provided. The device includes a connector coupled to a coaxial cable at one end. A relatively small, low inductive rectangular member is coupled to the connector at the other end. A conductive element is coupled to the rectangular member and is used for measuring and infecting the high frequency signal from and/or into a microwave transmission line positioned on a substrate. First and second rigid prongs are coupled to the rectangular member and are inserted into respective ground openings on the substrate. A network analyzer may be coupled to the cable for analyzing and generating the high frequency signal.

Abstract: A connector assembly for optical fiber cables which provides an increased density of optical fiber connections in a confined space. The assembly includes a front panel defining a first plane; and a connection panel having a face defining a plane having an angle with respect to the first plane.

Abstract: A YIG oscillator circuit including a closed loop control system which maximizes loop gain during start-up and minimizes loop gain after start-up to minimize gain compression. In one embodiment the closed loop control circuit includes a PIN diode coupled between the collector and base of a BJT, and comparison circuitry for comparing the YIG oscillator output voltage level with a reference voltage and providing a resulting feedback current to the PIN diode at the collector of the BJT. In operation, during start-up when the output voltage of the YIG oscillator is less than the reference voltage, the feedback current will be minimal and the PIN diode will reverse bias to maximize loop gain. When the output voltage approaches the reference voltage level, the feedback current will increase to forward bias the PIN diode to reduce loop gain and minimize gain compression. In a second embodiment, the PIN diode is not included, and the closed loop control circuit output signal is coupled to the emitter of the BJT.

Abstract: A receiver configured to measure phase change (.DELTA..phi.) in a signal transmitted from a microwave signal source, such as a cell site for cellular telephones, the transmitted signal including a carrier signal (F.sub.1) added to a modulation signal (F.sub.MOD), the receiver providing the phase change measurement (.DELTA..phi.) without further reference to the modulation signal (F.sub.MOD). Utilizing (.DELTA..phi.), distance from the transmitter can be calculated. The receiver includes one or more mixers for receiving the transmitted signal from the cell site and downconverting relative to an intermediate frequency signal (F.sub.IF) to produce an IF mixed signal including a sum IF mixed signal (F.sub.IF +F.sub.MOD) and a difference IF mixed signal (F.sub.IF -F.sub.MOD). The receiver then further includes components to demodulate the IF mixed signal to provide the modulated signal (F.sub.MOD) and the phase change measurement (.DELTA..phi.) with tracking of the intermediate frequency signal (F.sub.IF).

Abstract: A microwave test kit including a SWR bridge with one or more accompanying precision airlines for connecting between the test port of the SWR bridge and a test device. The SWR bridge includes a branch opposite its test port which includes an adapter having a connector with a center conductor support bead matching the center conductor support bead used in the precision airlines to compensate for impedance mismatch. The test kit may further include a standard 50 ohm termination and an offset termination, having an impedance other than 50 ohms, with the adapter of the SWR bridge configured to enable a user to selectively connect the standard termination to enable measurements to be made in an error averaging mode, or the offset termination to enable measurements to be made in a magnified mode.

Abstract: A method for updating automatic calibration to provide a perfect through connection during the calibration of the VNA. After the VNA is initially calibrated, a user may assess the calibration of the through connection to determine if the quality is sufficient. If the quality is insufficient, the user is able to replace the calibration parameters for the through connection used during initial calibration with parameters for a currently used through connection to create a perceived "perfect" through connection calibration.

Abstract: A simulator for testing the performance accuracy or calibrating a collision avoidance radar system. The simulator includes circuitry for receiving a signal from the collision avoidance radar system and for generating a signal tracking the frequency of the radar system. Circuitry is further included in the simulator utilizing the tracking signal to generate a signal offset in frequency from the collision avoidance radar system output signal and to transmit the offset signal to the collision avoidance radar. The offset is controlled so that the collision avoidance radar should indicate an object is located a distance (D) away. Circuitry is further included in the simulator so that the offset has a first value when the radar system output is increasing in frequency and a second value when the radar system output is decreasing in frequency. The first and second offset values are controlled so that the radar system should indicate an object is moving at a rate (dD/dt) upon receiving the offset signal.

Abstract: A power sensor that enables determination of the frequency of a microwave signal comprises a signal input that receives the microwave signal at a particular frequency, at least one sensor that produces a first and second output corresponding to the power of the microwave signal, and a means for coupling the signal input to the sensor so that the coupling means distinguishes the first output from the second output in order that the ratio of these outputs produces a unique value at the particular frequency.

Abstract: The present invention is directed to delta modulation in which the modulation level is optimized to improve overall system performance. A delta modulator in accordance with the invention includes a step size controller having a overload detector, a step size generator and a modulation level regulator. The overload detector monitors the output serial bit stream and produces a signal indicative of whether overload conditions are present. The step size generator produces steps of varying sizes in response to an input signal. The modulation level regulator monitors the signal output from the overload detector and outputs a modulated signal when the overload detector output has reached at least a certain threshold level. The modulation level regulator output is received at the step size generator input.

Abstract: An apparatus for characterizing transmission coefficient and group delay for a bi-directional two port device under test (DUT) using only one port of a measurement device, such as a vector network analyzer (VNA). The apparatus in one embodiment includes a programmable switch for coupling to one DUT port to selectively provide an open or a short. The measurement device is controlled to measure a reflection coefficient with the open at the DUT port and another reflection coefficient with a short at the DUT port. The measurement device then calculates a transmission coefficient magnitude value and a transmission coefficient phase angle for the DUT using the open reflection coefficient and the short reflection coefficient measurements. Group delay can then also be calculated using phase angle measurements at different frequencies.

Abstract: A metallic access test extender includes an office unit and a remote unit coupled to the office unit via a digital transmission system. A voltage controlled current source is included in the office unit and a voltage controlled voltage source in the remote unit. The voltage controlled current source is responsive to the voltage and current sensed at the remote unit load, and the voltage controlled voltage source is responsive to the voltage and current sensed at the input to the office unit. A shunt admittance which has a high impedance at DC and low frequencies is coupled to the office unit load.

Abstract: A test fixture for testing an integrated circuit having leads. The test fixture includes a substrate with top and bottom surfaces and holes extending from the top to the bottom surface. The integrated circuit is mounted on the top surface with each lead located above each hole. Contact flippers are located on the top surface of the substrate, with the contact flippers extending between the leads and the holes. Shuttle springs are located along the bottom surface and extend across the holes. Shuttles are inserted into each hole so that upon contact by the leads against the contact flippers, the shuttles move downward and against the upward pressure from the shuttle springs to provide a resilient connection between the test fixture and the integrated circuit.

Abstract: A calibration technique for a vector network analyzer (VNA) enabling calibration standards to be included internal to the VNA. To calibrate the VNA utilizing the internal calibration standards, error terms a, b and c of two two-port error boxes E are defined between the measurement ports and the reflectometer of the VNA wherein a=-det(E), b=e00 and c=e10. Error terms a, b and c are determined by measuring external calibration standards with known reflection coefficients connected directly to the measurement ports. Reflection coefficients for internal calibration standards are then determined using the error terms a, b and c to enable future automatic calibrations. To measure S-parameters of an arbitrary device under test (DUT), one embodiment of the present invention uses the Ferrero technique to measure a reciprocal thru with estimated S.sub.21 characteristics connected between ports A and B to determine an additional error term .alpha. for the error boxes E, where .alpha.=e01.sub.A /e.sub.01B.

Abstract: A low power dual sampler including two sampler switches with a step recovery diode (SRD) in each sampler switch. A local oscillator (LO) signal is provided through a power amplifier and transformer to baluns in the sampler switches without utilizing a power splitter, providing limited power loss to each balun. Each balun is configured to provide the LO signal to terminals of the SRD in a sampler switch without providing a termination to SRD impulses. Each sampler switch further includes series diodes connected across the terminals of each SRD switch with a junction of the series diodes connected to receive an RF signal, and the terminals of each SRD connected for providing an IF signal. To limit phase shift between SRD impulses, a temperature compensation circuit provides a DC offset voltage to each SRD.

Abstract: A handheld vector network analyzer (VNA) providing a wide bandwidth test signal F.sub.O utilizing a narrowband test signal synthesizer which provides the test signal through a frequency divider or harmonic generator. With a 550-1100 MHz narrowband test signal synthesizer, a test signal F.sub.O can range from 25 MHz to 3.3 GHz. To make a tracking synthesizer operate more independent of the test signal synthesizer, a LO signal is produced using the tracking synthesizer with its phase detector input connected through a frequency divider to the output of the test signal synthesizer. Synchronous detectors are further included which provide incident and reflected IF signals to take advantage of the maximum range of an A/D converter. To better enable operation in the presence of external signals, feedback is provided from the synchronous detectors to sweep the frequency of a reference oscillator.