Abstract: A reflectometer for use in measuring scattering (S-)parameters for a device under test (DUT) includes a test port, a radio frequency (RF) output signal source, and a local oscillator (LO) signal. The LO signal is used to downconvert the RF output signal to an incident IF signal. The reflectometer is useable as a first reflectometer with a second reflectometer such that the first and second reflectometers are phase synchronized by a synchronization signal. Phase and magnitude of transmission S-parameters of the DUT are measurable when the first reflectometer is used with the second reflectometer. The roles of the first and second reflectometers are reversible to allow for measurement of forward and reverse parameters. Further, the synchronization signal can be provided by one reflectometer to the other (or both can receive a separately generated synchronization signal) via a wire or fiber optic cable, for example, or via a wireless connection.

Abstract: An apparatus to detect interference in wireless signals, comprising an antenna for receiving a wireless signal; and wherein the apparatus is operable to identify a dominant waveform in the received signal; subtract the dominant waveform from the received signal to create a modified received signal; and repeat the above steps, recursively substituting the modified received signal for the received signal, until all adjusted reference waveforms have been subtracted.

Abstract: Systems and methods are provided for a replaceable internal open-short-load (OSL) calibrator and power monitor. A calibration system can include a test port; and a replaceable module including a first lookup table corresponding to an open-short-load (OSL) component and a second lookup table corresponding to a power measuring component.

Abstract: A method for measuring scattering parameters in a device under test (DUT) using a vector network analyzer (VNA), includes calibrating the VNA to generate corrections for deterministic setup defects and mapping a plurality of error terms based on a plurality of time indices, wherein each time indicia is associated with an error term. A test signal is transmitted to the DUT to obtain a measurement signal from the DUT in response to the test signal. The generated corrections to obtained measurements are time aligned based on the mapped error terms.

Abstract: In accordance with an embodiment, a measurement system includes a measurement instrument, a controller physically connected to the measurement instrument, and a portable user interface wirelessly connected to the controller. The portable user interface is operable to remotely monitor and control the measurement instrument.

Abstract: A method of calibrating a passive intermodulation (PIM) measurement device configured to transmit radio frequency (RF) signals and receive PIM signals using a directional antenna includes arranging the PIM measurement device connected to the directional antenna so that the directional antenna is configured to transmit an RF signal having a substantially unobstructed boresight axis, transmitting the RF signal, and obtaining a PIM measurement using the PIM measurement device. The PIM measurement device can then be calibrated based on the obtained PIM measurement.

Abstract: An apparatus to detect interference in wireless signals, comprising an antenna for receiving a wireless signal; and wherein the apparatus is operable to identify a dominant waveform in the received signal; subtract the dominant waveform from the received signal to create a modified received signal; and repeat the above steps, recursively substituting the modified received signal for the received signal, until all adjusted reference waveforms have been subtracted.

Abstract: A method of estimating a location of an interference signal source includes using a first antenna configured to receive a signal from the interference signal source and using a second antenna arranged proximate to the first antenna and configured to receive global positioning system (GPS) signals. An initial trend in variation in power of a received signal from the interference signal source is determined relative to a position of the second antenna, wherein upon determining the initial trend, the initial trend is a current trend. In an iterative manner, the second antenna is directed to be repositioned and a current trend in the peak measurement in power is observed until an estimate of the location of the interference signal source is determined.

Abstract: In an embodiment, a method for calculating PIM associated with a DUT comprises obtaining a first measurement of PIM with the DUT connected to the measuring instrument, introducing a shift in a phase offset of PIM produced at the DUT in response to test signals generated by the measuring instrument, obtaining, upon introducing the shift, a second measurement of PIM with the DUT connected to the measuring instrument and calculating the PIM associated with the DUT based on the first measurement and the second measurement.

Abstract: A method to detect audio frame losses over a link to a device under test (DUT), such as a User Equipment (UE), includes preparing an input sequence, combining the input sequence into an input audio signal, submitting the input audio signal to an encoder, transporting the encoded signal over the link, obtaining a continuous output audio signal from decoding the transported signal, decomposing the continuous output audio signal into an output sequence, and determining one or more lost frames based on a comparison of one or more characteristics of the input sequence and the output sequence. Preparing the input sequence can include preparing a sequence of a plurality of input snippets, each input snippet having one or more audio characteristics, the preparing such that consecutive input snippets have one or more audio characteristics that differ by a predetermined measure.

Abstract: A reflectometer for use in measuring scattering (S-) parameters for a device under test (DUT) includes a test port, a radio frequency (RF) output signal source, and a local oscillator (LO) signal. The LO signal is used to downconvert the RF output signal to an incident IF signal. The reflectometer is useable as a master reflectometer with a slave reflectometer such that the master reflectometer provides the slave reflectometer with a synchronization signal to synchronize signals generated by the second reflectometer to the incident IF signal. Phase and magnitude of transmission S-parameters of the DUT are measurable when the reflectometer is used as the master reflectometer in combination with the slave reflectometer. The master reflectometer and the slave reflectometer can be reconfigurable to reverse the master/server roles of the reflectometers.

Abstract: A system for adaptively eliminating intermods from a spectrum generated by combining two or more signals in a component or circuit includes a sampler for sampling an output signal of the component or circuit, a signal source for generating a conversion signal having a frequency matched to a target intermod of the spectrum, and a cancellation circuit to generate a cancellation phasor. The cancellation circuit is configured to receive the generated conversion signal and the sampled output signal and generate a cancellation phasor therefrom having a phase and amplitude configured to cancel the target intermod. A combining network can combine the cancellation phasor into the component or circuit to cancel the target intermod from the spectrum.

Abstract: A frequency-scalable device for interfacing a planar medium with a coaxial medium to propagate a primary signal, the device comprises a transition medium connectable between the coaxial medium and the planar medium. The transition medium suppresses excitation of secondary electrical signals by the primary signal when the primary signal is propagated through the transition medium at a frequency below an upper limit.

Abstract: A protection device usable with a signal measurement device to limit power level of radio frequency (RF) signals propagated to the signal measurement device can include a direct current (DC) block capacitor, a variable impedance limiter, and a detector. The variable impedance limiter includes a PIN diode electrically connected with a primary signal path of the protection device along a limiter signal path. The detector includes a Schottky detector diode and a limiting resistor electrically connected with the primary signal path along a detector signal path. The detector is configured to generate a DC bias current to adjust resistance of the variable impedance limiter in response to an RF signal.

Abstract: An embodiment of a low power system for measuring passive intermodulation (PIM) includes a port, a test signal source, a dielectric frequency domain multiplexer and a receiver. The test signal source provides a test signal including two tones each capable of producing a signal at the test port of amplitude +30 decibels referenced to one milliwatt (dBm) or less. The dielectric frequency domain multiplexer connected with the port and the test signal source and is adapted to multiplex the test signal provided by the test signal source and a measurement signal obtained at the port. The receiver receives the multiplexed measurement signal from the dielectric frequency domain multiplexer and provides a signal indicative of PIM.

Abstract: A system adapted to measure electrical performance of a device under test (DUT) having two or more ports includes a plurality of signal sources synchronized and configured to generated signals simultaneously, a plurality of first signal paths to obtain transmitted and reflected signals from the DUT, a plurality of second signal paths to obtain incident signals from the signal sources, and a receiver for receiving the reflected, transmitted and incident signals obtained at the first signal paths and the second signal paths. The receiver is adapted to separate the reflected and the transmitted signals obtained from each of the first signal paths. The signal sources are configured to each generate a signal having a frequency offset from each of the others of the signal sources by a known frequency delta.

Abstract: A Passive Intermodulation (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 down conversion 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: A spectrum analyzer that provides from below 9 kHz to above 20 GHz operation range while remaining hand-held. The spectrum analyzer includes an integrated precision stand-alone step attenuator that does not rely on printed circuit board (PCB) mounted circuit elements within the signal path. Further, a PIN diplexing switch separates signals into different base-band and highband paths. The baseband path includes a pre-amplifier for low frequency signals, while the higher frequency bands may not necessarily include a pre-amplifier. The highband path incorporates multi-throw MMIC PIN diode switches to selectively filter different bands of input signals.

Abstract: In an embodiment, a system for measuring high frequency response of a DUT having improved power leveling includes a signal source, a modulator, an upconverter, and a leveling loop having dynamic gain adjustment. The signal source generates a test signal and the modulator modulates the amplitude of the generated test signal to target a requested power. The converter multiplies a frequency of the test signal. The leveling loop is configured to detect an intermediate frequency (IF) signal generated in response to the upconverted test signal. Modulation of the amplitude of the generated test signal by the modulator is adjustable based on the IF signal detected by the leveling loop.

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.