Abstract: A photovoltaic mounting apparatus for use with a solar panel includes a base element having an elongated upper portion and a lower portion. The upper portion is structured for engagement with a rooftop by being positioning underneath the shingles of a rooftop and secured thereto through the apertures of the upper portion and/or lower portion of the base element. One or more support elements extend perpendicularly from the lower portion of the base element. A front plate is situated upon the support elements and is parallel to the base element and structured for engagement with the solar panel.

Abstract: A spectrum analyzer is combined with the VNA in a housing measuring approximately 4 pounds with the spectrum analyzer portion operating from slightly above DC to above 3.0 GHz. The components for the spectrum analyzer are provided on a separate printed circuit board from the two printed circuit boards for the display and VNA components in the housing. The design of components for the printed circuit board enable a significant reduction of size from a typical spectrum analyzer which weighs 40 pounds or more and measures on the order of 2 feet by 3 feet by 0.5 feet.

Abstract: A frequency synthesizer including a divide by R frequency divider providing a first input of a phase detector, a divide by N frequency divider providing a second input of the phase detector, and a voltage control oscillator (VCO) receiving the output of the phase detector and providing an input to the divide by N frequency divider, the VCO output signal being transitioned by varying the frequency division number R. The frequency division number N may also be varied to transition the VCO output signal frequency. A reference oscillator provides an input to the variable R frequency divider and may have its frequency varied to limit resolution error. For greater resolution, multiple frequency synthesizers with divide by R and N frequency dividers having variable frequency division numbers may be connected using mixers to provide a “ratio sum” synthesizer having an output frequency proportional to a sum of N/R ratios.

Abstract: A linear phase detector circuit enables locking of two frequency sources which can operate in the range of 10 GHz with a minimal frequency offset, such as from 0 Hz to 50 KHz. With the frequency sources operating at frequencies F1 and F2 with an offset F2−F1 or F1−F2, the phase detector generates a DC signal indicating a phase offset between a signal F2−F1 or F1−F2 derived from the frequency sources and a reference operating at the desired offset F2−F1 or F1−F2, while eliminating any 2(F2−F1) or 2(F1−F2) component. In this way, the phase detector allows a substantially higher loop bandwidth than the offset F2−F1 or F1−F2, and allows phase tracking independent of the offset. The phase locking circuitry is useful in applications such as providing a variable Doppler shift in a radar signal.

Abstract: A frequency reference is employed to correct a frequency error in a signal synthesizer. The frequency reference provides a reference frequency with a parts per million deviation from the reference's nominal frequency. The reference frequency parts per million deviation is equal in magnitude to the parts per million deviation of the frequency error from a desired signal synthesizer output frequency. The deviation in the reference frequency offsets the deviation from the desired output frequency to significantly reduce the frequency error. The frequency reference includes a voltage controlled oscillator, programmable voltage generator, and voltage control engine. The reference frequency is set by the voltage controlled oscillator in response to a frequency setting voltage from the programmable voltage generator. The voltage control engine is coupled to the programmable voltage generator to provide a voltage setting value that controls the frequency setting voltage.

Abstract: A two port handheld VNA enabling both reflection and transmission measurements to be made over a range of 25 MHz to 3.3 GHz frequency range. The handheld VNA includes a tracking synthesizer which generates a LO signal without a direct connection to a reference oscillator, enabling resolution of the LO signal to be independent of a generated RF test signal. Synchronous detectors are further included to provide incident, reflected, and transmitted IF signals to an A/D converter. To enable operation in the presence of external signals, a feedback dither line is provided from one of the synchronous detector outputs to sweep the frequency of the reference oscillator. The handheld VNA also is configured to optionally operate as a frequency monitor to determine the frequency range and power level of incoming signals without upconverting and downconverting to eliminate images as typically done in a spectrum analyzer. The frequency monitoring circuit operates by dividing the frequency range to be monitored into bins.

Abstract: A frequency divider includes a mixer having a first input connectable to a reference oscillator and a second input connectable from the reference oscillator through a frequency synthesizer to the second input of the mixer. The mixer provides an output signal to a filter, which provides a frequency divider output. The frequency synthesizer provides an output signal having a frequency of (N+1)/N or (N-1)/N times the input F.sub.IN from the reference oscillator. With the frequency synthesizer providing the signal F.sub.IN (N+1)/N, or F.sub.IN (N-1)/N, the output of the mixer provides the signal having the frequency F.sub.IN /N and can utilize a single filter to eliminate undesired mixer outputs. Further, the frequency synthesizer can be configured to utilize an oscillator which operates over the same frequency range as the reference oscillator.

Abstract: An automobile collision avoidance radar antenna alignment system includes a first interferometer (506) with antennas (501) and (503) for alignment along an azimuth (x) axis of the collision avoidance radar antenna, and a second interferometer (508) with antennas (502) and (504) for alignment along an elevation (y) axis of the collision avoidance radar. Difference azimuth (.DELTA..sub.AZ) and difference elevation (.DELTA..sub.EL) outputs of the interferometers (506) and (508) are added (.DELTA..sub.T =.DELTA..sub.AZ +.DELTA..sub.EL) with the amplitude of (.DELTA..sub.T) provided at a power detector (526). Sum azimuth (.SIGMA..sub.AZ) and sum elevation (.SIGMA..sub.AZ) are added (.SIGMA..sub.T =.SIGMA..sub.AZ +.SIGMA..sub.EL) with the amplitude of (.SIGMA..sub.T) provided to a power detector (547). To align a collision avoidance radar antenna, the antennas of the antenna alignment system are positioned with a centerline parallel to the thrust vector of the automobile using a laser beam fixture 204.

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 two port handheld VNA enabling both reflection and transmission measurements to be made over a range of 25 MHz to 3.3 GHz frequency range. The handheld VNA includes a tracking synthesizer which generates a LO signal without a direct connection to a reference oscillator, enabling resolution of the LO signal to be independent of a generated RF test signal. synchronous detectors are further included to provide incident, reflected, and transmitted IF signals to an A/D converter. To enable operation in the presence of external signals, a feedback dither line is provided from one of the synchronous detector outputs to sweep the frequency of the reference oscillator. The handheld VNA also is configured to optionally operate as a frequency monitor to determine the frequency range and power level of incoming signals without upconverting and downconverting to eliminate images as typically done in a spectrum analyzer. The frequency monitoring circuit operates by dividing the frequency range to be monitored into bins.

Abstract: A vector network analyzer (VNA) has a first harmonic generator multiplying an RF signal by an odd number M1 to produce incident and reflected test signals received at inputs of mixers providing IF signals. A second harmonic generator multiplies an LO signal by an odd number M2 offset by 2 from M1 to provide signals to additional inputs of the mixers providing IF signals. With the harmonic generators providing odd harmonics separated by 2, a single filter removes remaining harmonics from IF signals provided from each mixer. Each harmonic generator includes two step recovery diodes (SRDs) with opposing ends connecting the signal path to ground, the SRDs functioning to cancel even harmonics. A first coupler provides the output of the first harmonic generator to the mixers, the first coupler having a minimal size enabling its output power to increase with frequency.

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 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: 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 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.

Abstract: A measurement system is provided which comprises: source circuit for receiving feedback signals and for providing respective signals at respective discrete frequencies in a prescribed microwave frequency range, wherein the respective provided signals at respective discrete frequencies are substantially phase locked to at least one downconverted signal in response to the feedback signals; downconverting circuit for linearly downconverting the respective provided signals and for providing the at least one respective downconverted signal; and phase detector circuit for receiving the at least one respective downconverted signal and for providing the feedback signals.

Abstract: An ultra low phase noise microwave synthesizer for providing an output signal having a frequency F.sub.O of from 2 GHz to 20 GHz using a first voltage controlled oscillator (VCO), a first frequency comparing circuit for driving said first VCO to a first selected frequency (F.sub.idle), a first circuit including a first harmonic sampler for phase locking said first VCO to said first selected frequency (F.sub.idle), a second VCO, a second frequency comparing circuit coupled to said first VCO for driving said second VCO to a second selected frequency (F.sub.coarse), a second circuit coupled to said first VCO including a second harmonic sampler for phase locking said second VCO to said second selected frequency (F.sub.coarse), a third VCO, and a third circuit coupled to said second VCO including a third harmonic sampler for phase locking said third VCO to said frequency F.sub.O.

Abstract: A phase locked loop includes a linear phase detector responsive to a first signal having a predetermined range of frequencies and a second signal for comparing the relative phase of the first signal and the second signal, and a loop gain stabilization circuit coupled between the source of the first signal and the linear phase detector for reducing the magnitude of variations in the loop gain of the phase locked loop over the predetermined range of frequencies of the first signal source. An embodiment of the linear phase detector comprises a harmonic sampler/presteer circuit. The construction and operation of the loop gain stabilization circuit depends on whether the phase locked loop is being used in a frequency multiplying or dividing circuit.

Abstract: Frequency divider and multiplier circuits are provided comprising a voltage controlled oscillator, a presteer circuit comprising a frequency comparator, a sampling phase detector circuit comprising a sampler, a pair of prescalers for providing frequencies in the divider/multiplier circuits by a predetermined number D, a programmable divider for dividing one of the frequencies in the divider/multiplier circuits by a selectable N and a summing circuit. In operation, the presteer circuit drives the VCO toward a predetermined frequency. When the VCO reaches a predetermined frequency, the output of the presteer circuit is disabled and the sampling phase detector takes over, locking the VCO to the predetermined desired frequency.