Abstract: An embodiment of a method in accordance with the present invention for determining a distance to a source of passive intermodulation (PIM) in a radio frequency (RF) transmit/receive system comprises a two step process. As a first step, a first and second signal with frequencies in a transmit band are generated at a first power and a third order harmonic signal generated by a source of PIM within the system is obtained in the receive band. If the magnitude of the PIM exceeds a noise threshold, a second step is performed. The second step includes generating a third and fourth signal at a second power higher than the first power to obtain a higher order harmonic signal generated by the source of PIM. The PIM magnitude and a distance to the source of the PIM are calculated using the higher order harmonic signal.

Abstract: A system for communicating information about one or both of an object with a scanned surface and an object at least partially concealed by the scanned surface comprises a scanner and a projector. The scanner is adapted to scan the surface to obtain information that is unattainable through visual observation. The projector is adapted to project an image related to the obtained information onto the scanned surface. The projected image is a dynamic image that is mapped in substantially real-time to a location on the scanned surface from or through which the information is obtained.

Abstract: An embodiment of a system for generating a low phase noise sine wave includes a variable signal source for generating a signal a series of octave dividing stages connected with the variable signal source, an input divider connected with the variable signal source, and a second series of octave dividing stages connected with an output of the pre-input frequency divider. Each octave dividing stage generating a successive octave of the generated signal using a frequency divider, a sine look up table, and a low pass filter.

Abstract: A system for measuring passive intermodulation (PIM) comprises a port connectable with a load and a PIM source, a test signal source providing a test signal having components of two or more frequencies, and a receiver including a phase-coherent detector to receive a reflected signal obtained at the port in response to the provided test signal. The phase-coherent detector has an output that provides a signal indicative of PIM. A reference signal source connected with the phase-coherent detector provides a reference signal derived from the test signal. A signal combiner having a first input connected with the output of the phase-coherent detector, a second input connectable with storing a measurement of residual PIM generated by the apparatus, and removes the residual PIM from the signal indicative of PIM and provides measured PIM of the PIM source at the output.

Abstract: In accordance with an embodiment, an apparatus for analyzing signals comprises a spectrum analyzer and a frequency extension module. The spectrum analyzer includes an IF switch which switches between an internal IF signal and an external IF signal, and a LO coupler which is configured to output a portion of one or more LO signals. The frequency extension module is configured to receive the one or more LO signals from the spectrum analyzer and send an IF signal to the spectrum analyzer. A diplexer band switch is used to direct the low band signals to the spectrum analyzer and to direct the high band signals to the frequency extension module where they are downconverted to the external IF which is output to the IF switch.

Abstract: A device to measure a passive intermodulation (PIM) creating component is provided that uses minimal average power. For a PIM measurement, two separate signals F1 and F2 are generated to simulate signals, such as from two different types of cell phone operating bands being transmitted in the same area or two different transmit frequencies within one cell phone operating band. PIMs are measured to assure interference is not created on one of the cell phone bands. Minimal power is used by connecting pulse width modulators (PWM) to provide DC power to the high power amplifiers (HPA) creating the signals F1 and F2. By controlling the duty cycle of the PWM to limit ON time of the HPAs to approximately 10%, significant average power savings occur. Size is also reduced with reduced power consumption because heat sinks and other cooling components are not required.

Abstract: A method to measure a brightness response of a camera comprises obtaining a plurality of brightness measurements and determining for one or more of the plurality of brightness measurements a captured brightness of the captured image. Obtaining each of the plurality of brightness measurements includes presenting to the camera at least one test sample having known brightness, capturing via the camera an image of the at least one test sample, and presenting to the camera at least one compensation sample having compensating brightness selected based on the known brightness of the at least one test sample. The at least one test sample and the at least one compensation sample are selectable and presentable in combination such that an average exposure interpreted by the camera is substantially the same for each of the plurality of brightness measurements.

Abstract: Shockline-based samplers of a vector-network analyzer (VNA) have enhanced dynamic range by using a dynamic bias network applied to the non-linear transmission lines (NLTLs) or shocklines. The bias voltage applied to the NLTL provides direct control over the falling-edge shockline compression, and thus the insertion loss and overall RF bandwidth of the sampler. Alternating between a forward bias voltage to turn off a shockline sampler when it is not needed and thereby reducing spurious generation and improving isolation can be alternatively applied with a reverse bias voltage to turn on the shockline sampler in a normal operation mode. By measuring the shockline output and providing feedback in the reverse-bias mode, the bias voltage can be dynamically adjusted to significantly increase the performance of the NLTL based sampler. In the presence of a strong positive bias voltage, the incoming LO and its harmonics experience large ohmic losses thus preventing gating pulses from forming in the shockline.

Abstract: An embodiment of a system for determining a distance and magnitude to one or more unknown passive intermodulation (PIM) sources associated with a network under test comprises a scalar PIM measuring instrument and a reference PIM source. The scalar PIM measuring instrument has an output frequency that is systematically changeable to produce a series of response signals of varying frequency and the reference PIM source is configured to introduce a reflected signal to the scalar PIM measuring instrument in response to the output frequency. The scalar PIM measuring instrument can perform data processing algorithms allowing the extraction of distance and magnitude information about the unknown PIM sources located along the network under test from scalar data received by the scalar PIM measuring instrument. The scalar data received by the scalar PIM measuring instrument represents a combination of signals from the unknown PIM sources and the reference PIM source.

Abstract: A test system is provided to test both voice and video quality of the connection for a large number of mobile phones, tablets, laptops or other user transmit/receive devices from a central location. The quality can be expressed as a Mean Opinion Score (MOS) and the uplink and downlink connection quality can be separately estimated. The system allows the use of media fragments that are characteristic of an end user and allows video data to be measured at the time and location that the user typically makes calls.

Abstract: Systems and methods are provided for calibrating a receiver in an RF system having a device under test (DUT) configured to receive at least one input signal and output at least one response signal. A method comprises setting a drive level of the RF system and making a pair of measurements at the drive level. Each of the measurements is made in a different gain state at a receiver. The method also comprises calculating a calibration factor for the receiver which is a ratio of the pair of measurements. These systems and methods can be used to calibrate receivers while preserving vector information and removing dynamic match effects.

Abstract: A device for use with a passive intermodulation (PIM) measuring instrument comprises a load, a connector associated with the load, and a PIM standard adapted to selectively introduce a PIM intervening between the load and the connector. The load is adapted to be electrically connected with the PIM measuring instrument by connecting the connector to a port of the measuring instrument and the PIM standard is capable of selectively introducing the PIM without disconnecting the connector from the port.

Abstract: A PIM measurement circuit enables making forward and reverse PIM measurements on any 1 port (reflection) or 2 port (transmission) device with the ability to determine in distance where individual PIM impairments are located as well as their magnitude. The PIM measurement circuit includes two frequency sources that are provided through a combiner for a CW characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a saw tooth offset sweep generator attached to one of the two frequency sources. With downconversion and processing of signals from the PIM impairments, the FM signal provides a frequency variation that is converted using a Fourier transform or spectrum analysis for separation of frequencies, enabling determination of the distance of the PIM sources as well as their magnitudes.

Abstract: An automated method for testing audio signal quality of cell phone transmissions provides a Mean Opinion Score (MOS) output using inexpensive test components. The test system uses a server computer to eliminate the need for expensive faders used in a bench test system. The server computer manipulates data packets from the reference media file to simulate impairments, including losses, errors, noise and jitter, at a much lower cost than using actual faders. Transmission through two separate radio access networks RANs is provided to simulate two parties communicating using separate mobile devices (an end-to-end test solution) with a single cell phone.

Abstract: In accordance with an embodiment, a system for measuring passive intermodulation (PIM), comprises a base unit, which includes frequency-independent components, and a frequency-dependent plugin, which includes frequency-dependent components and is associated with a particular frequency band. The frequency-dependent plugin can be combined with the base unit to measure PIM over the particular frequency band.

Abstract: Systems and methods are provided for improving frequency resolution in a phase locked loop having an oscillator and a phase detector. A method comprises receiving a reference signal and generating an output signal having a phase relationship with the reference signal and receiving the output signal at a fractional divider connected between the oscillator and the phase detector in a feedback loop, wherein the fractional divider includes a plurality of configurable parameters. The method also comprises adjusting a value of the modulus parameter to increase frequency resolution.

Abstract: A portable hand-held battery powered eye pattern analyzer is provided that can analyze signal quality of a high speed digital communication network. The system is 10 times smaller in volume and 4 times lighter than the bench-top equivalent instruments. The system includes a housing containing a display, keypad, power supply, battery pack, and RF sampler board along with connections for electrical inputs, optical inputs, clock signal inputs, and clock recovery signal inputs. The sampler circuit board can support connections, such as a USB plug for attachment to a personal computer. The RF sampler board contains the following elements: (1) A dual sampler for two-channel electrical inputs. (2) An Optical-to-Electrical O/E conversion module. (3) A clock recovery unit (CRU) module to recover the clock from the electrical or optical pulse pattern signal. (4) A trigger circuit that accepts an input clock and uses that clock to trigger the sampling of the data signal.

Abstract: A high-frequency VNA system is provided using non-linear transmission line (NLTL or shockline) based samplers configured to provide scalable operation characteristics. Scaling to adjust noise performance vs. frequency is accomplished as follows: (1) increasing or decreasing the fall time of a shockline's output voltage waveform. This is accomplished by changing the number of Schottky varactors in a shockline, as well as changing the shockline's Bragg cutoff frequency by setting the spacing between Schottky varactors; (2) changing the structure of the pulse-forming network connected with the sampler by changing the length of the differentiator arms in the sampler pulse-forming network; and (3) changing the LO signal frequency applied to the shockline. Multiple NLTL based samplers are multiplexed to form a broadband reflectometer with the multiplexing circuitry selectively connecting one of the NLTL based sampler segments at a time to allow user selection of a desired performance vs.

Abstract: A distance to PIM measurement circuit is made using a device such as an AWS transceiver that has separate transmit and receive bands. With a typical AWS transceiver placed in close proximity to a PCS transceiver, the AWS device will include a band reject filter to eliminate interference from the PCS signals. The PIM measurement circuit includes two frequency sources F1 and F2 that are provided through a combiner for characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a offset sweep generator attached to one of the two frequency sources. To avoid frequencies blocked by the band reject filter, a desired harmonic of a test PIM harmonic signal is selected outside the band of the band reject filter.

Abstract: A portable frequency synthesizer is provided with fine tuning over a broad bandwidth using a Fractional N type Delta Sum Phase Locked Loop circuit that enables elimination of boundary value spurs. In the system, frequencies where spurs occur are calculated to define a region of fractional N values that cannot be used with a first time base. To avoid the boundary spurs, a second time base reference is selected that can generate boundary spurs that do not overlap with the first time base. Circuitry is provided to select the appropriate time base and the fractional N values to generate desired output frequencies throughout the synthesizer range while avoiding the boundary spurs.