Abstract: A measuring instrument for detecting a source of passive intermodulation (PIM) includes a signal source, a reference signal source, and a first transmitter module and a second transmitter module each configured to receive a signal from the signal source and a reference signal from the reference signal source and generate a tone at a first frequency and a second frequency, respectively. The measuring instrument further includes a receiver and a receiver module configured to receive the signal from the signal source and a harmonic of the test signal generated by a source of PIM to generate a sample signal at the fixed frequency of the reference signal. The receiver is configured to determine a shift in phase between the reference signal and the sample signal. The receiver determines an estimate of distance to the source of PIM using determinations of the shift in phase as the signal source is swept.

Abstract: In accordance with an embodiment, a synchronous N pulse burst generator includes an input for an intermediate frequency trigger signal and a signal path extending from the input. The signal path includes a series of N AND gates and an OR gate. Each AND gate is arranged to receive two inputs from the signal path. The signal path introduces a time delay between the two inputs received by each AND gate. A second input of the two inputs is inverted. The signal path introduces the time delay between successive AND gates from the series of N AND gates. An OR gate receives outputs from the series of N AND gates and outputs an A/D clock signal.

Abstract: A measuring instrument for measuring electrical characteristics of a device under test (DUT) includes a signal generator for generating a synchronization signal transmittable to a receiver and a phase shifter. The measuring instrument is configured to receive a retransmission of the synchronization signal from the receiver. The phase shifter configured to receive the synchronization signal from the signal generator and the retransmission of the synchronization signal from the receiver and shift a phase of the synchronization signal so that pulse edges of the synchronization signal are aligned at the measuring instrument and the receiver.

Abstract: In accordance with an embodiment, a method of providing a gasket on an electromagnetic interference (EMI) shield adapted to isolate a plurality of components of a measurement instrument includes obtaining a shield bottom of the EMI shield, cleaning the shield bottom, plugging threaded holes within the shield bottom so that threads of the threaded holes are substantially unexposed, applying a gasket layer to the shield bottom, and unplugging the threaded holes so that the threads are exposed.

Abstract: A method of eliminating spurs in measurements of an electrical response of a device under test (OUT) obtained uses a measurement instrument including a mixer and a receiver. The measurement instrument is configured to generate, via the mixer, an intermediate frequency (IF) signal for use by the receiver from a radio frequency (RF) signal and a local oscillator (LO) signal. Input is received from a user at the measurement instrument and includes start frequency and end frequency. Parameters for a frequency sweep are generated based on the input. A measurement for each frequency of the frequency sweep is calculated using averaging of a plurality of samples obtained at that frequency. Frequencies are identified within the frequency sweep at which spurs will occur due to the measurement instrument. The parameters for a frequency of the frequency sweep at which a spur will occur are modified so that a null for a measurement at the frequency falls on the spur.

Abstract: A system for measuring electrical characteristics of a device under test (DUT) includes a measuring instrument adapted to be connected with the DUT for transmitting tests signals to the DUT, a receiver adapted to be connected with the DUT and arranged remote from the measuring instrument, an optical transceiver having a first coupler electrically connectable with the measuring instrument and a second coupler electrically connectable with the receiver, and a first and second free space transceivers connected to respective couplers by fiber optic cable. The measuring instrument includes a clock signal generated from a synchronization signal. The synchronization signal is converted to an optical signal by the optical transceiver and transmitted from the first free space transceiver to the second free space transceiver. The second coupler converts the optical signal to the synchronization signal and a clock signal of the receiver is locked to the synchronization signal.

Abstract: A measurement instrument for measuring electrical characteristics of a device under test (DUT) includes a synchronization signal generator configured to generate a synchronization signal transmittable from the measurement instrument to a receiver. The synchronization generator comprises a phase-locked loop (PLL) that locks the phase of the LO signal to the synchronization signal. The A/D clock signal is generated from the synchronization signal.

Abstract: A measurement instrument for measuring electrical characteristics of a device under test (DUT) includes a synchronization signal generator, a coarse phase detection counter and a fine phase detection counter. The synchronization signal generator is connectable with a receiver via a fiber optic cable and a duplexer configured to transmit a synchronization signal from the measurement instrument to the receiver and retransmit the received synchronization signal from the receiver to the measurement instrument. The coarse phase detection counter and the fine phase detection counter are configured to determine one or both of a distance from the receiver to the measurement instrument and a phase shift in the synchronization signal between the receiver and the measurement instrument.

Abstract: A measurement instrument for measuring electrical characteristics of a device under test (DUT) includes a synchronization signal generator for generating a synchronization signal transmittable to a receiver, a voltage controlled phase shifter (VCPS) connected with the synchronization signal generator and a phase-to-voltage converter configured to drive the VCPS. The synchronization signal is transmitted via a duplexer configured to transmit the synchronization signal from the measurement instrument to the receiver via a fiber optic cable and retransmit the received synchronization signal from the receiver to the measurement instrument via the fiber optic cable. The phase-to-voltage converter receives as inputs the synchronization signal input to the VCPS, the synchronization signal output from the VCPS and the retransmitted synchronization signal received at the measurement instrument from the receiver. An output of the phase-to-voltage converter is provided as input to the VCPS.

Abstract: In an embodiment, a method for measuring passive intermodulation (PIM) associated with a device under test (DUT) includes generating a test signal using a measuring instrument and obtaining measurements of PIM for the DUT. The test signal comprises two or more tones each amplified to a target output power by a respective amplifier according to a duty cycle. Measurements are obtained by the measuring instrument during an active portion of each duty cycle over a sweep of frequencies. PIM is calculated for the DUT by averaging a plurality of measurements obtained for each frequency from the sweep of frequencies. The duty cycle is determined based on the target output power.

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: 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: 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: 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 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.