Abstract: A method of determining group delay between periodic radio frequency (RF) signals received at a narrow-band coherent receivers includes receiving a first periodic RF signal at a first coherent receiver in the frequency domain, receiving a second periodic RF signal at a second coherent receiver in the frequency domain, which is delayed with respect to the first periodic RF signal, the first and second periodic signals having the same period and carrier frequency; determining a cross-spectrum signal of the first and second periodic RF signals in the frequency domain, the cross-spectrum signal including amplitudes and phases versus frequency; calculating a slope of phase of the cross-spectrum signal at frequencies over at least a portion of a bandwidth of the cross-spectrum signal; and determining a group delay between the first and second periodic RF signals to be the slope of phase of the cross-spectrum signal.

Abstract: A method is provided for calibrating a multiport measurement system having a local oscillator and a respective receiver associated with each port. The method includes performing a relative calibration by vector calibrating ports of the multiport measurement system and generating relative error-correction terms for the ports. Further, the method includes performing an absolute calibration by calibrating an amplitude response of the receivers of the multiport measurement system, and removing a local oscillator unknown phase response using a single phase reference coupled to a vector calibrated port and transferring cross-frequency phase correction terms from this vector calibrated port to the receivers of the other vector calibrated ports.

Abstract: A method determines operating characteristics of a signal generator. The method includes performing a first set of measurements of an output signal generated by the signal generator and corresponding reflected signal, where the first set of measurements is performed over multiple frequencies and amplitudes of the output signal; applying an external signal to the output port of the signal generator; performing a second set of measurements of the output signal and corresponding reflected signal while the external signal is being applied to the output port, where the second set of measurements is performed over frequencies and amplitudes of the output signal, the external signal having the same frequency as the output signal for each measurement of the second set of measurements. A set of coefficients describing the operating characteristics of the signal generator is determined by processing results of the first and second sets of measurements through a non-linear model.

Abstract: A method determines operating characteristics of a signal generator. The method includes performing a first set of measurements of an output signal generated by the signal generator and corresponding reflected signal, where the first set of measurements is performed over multiple frequencies and amplitudes of the output signal; applying an external signal to the output port of the signal generator; performing a second set of measurements of the output signal and corresponding reflected signal while the external signal is being applied to the output port, where the second set of measurements is performed over frequencies and amplitudes of the output signal, the external signal having the same frequency as the output signal for each measurement of the second set of measurements. A set of coefficients describing the operating characteristics of the signal generator is determined by processing results of the first and second sets of measurements through a non-linear model.

Abstract: A method and system of providing a phase reference signal includes generating a reference signal having a reference frequency, modulating the reference signal at a modulation frequency lower than the reference frequency to obtain a modulated drive signal, receiving the modulated drive signal at a phase reference, and generating the phase reference signal based on the modulated drive signal. The phase reference signal including multiple reference tones having corresponding tone frequencies clustered around multiples of the reference frequency. A spacing between adjacent tones of the multiple reference tones is the same as the modulation frequency or an integer multiple of the modulation frequency.

Abstract: A method and system of providing a phase reference signal includes generating a reference signal having a reference frequency, modulating the reference signal at a modulation frequency lower than the reference frequency to obtain a modulated drive signal, receiving the modulated drive signal at a phase reference, and generating the phase reference signal based on the modulated drive signal. The phase reference signal including multiple reference tones having corresponding tone frequencies clustered around multiples of the reference frequency. A spacing between adjacent tones of the multiple reference tones is the same as the modulation frequency or an integer multiple of the modulation frequency.

Abstract: A method is presented where the phase trace is offset for each sweep such that the first point is always at zero degrees. The resulting traces are then averaged. The average reduces the noise in the phase trace and results in a less noisy group delay trace.

Abstract: A method for eliminating the systematic measurement errors from a measurement system, for example a vector network analyzer, such that an accurate representation of the behavior of a nonlinear device can be measured or characterized. The cross-frequency phase and absolute amplitude of the measured voltage waves applied to and emanating from the nonlinear device are measured and error corrected. These waves may be used for nonlinear device characterization or modeling.

Abstract: The invention measures the X-parameters (or large-signal S and T scattering functions, sometimes called linearized scattering functions, which are the correct way to define “large-signal S-parameters”) with only two distinct phases for small-signals on a frequency grid established by intermodulation frequencies and harmonics of the large-tones, with guaranteed well-conditioned data from which the X-parameter functions can be solved explicitly, without the need for regression, and not limited by performance limits of the reference generator or phase-noise.

Abstract: A test system and method which employs a filter bank to select different spectral components of a pulsed measurement signal. The filter bank utilizes filter nulls to suppress non-selected spectral components. After filtering the selected spectral components, the spectral components are combined to provide for a measurement signal which is analyzed to determine characteristics of a device being tested. The characteristics of the filters can be adjusted in response to a change in the characteristics of a pulsed signal applied to the device under test, so that the selected spectral components will correspond to desired spectral components generated by the pulsed signal applied to the device under test.

Abstract: The invention measures the X-parameters (or large-signal S and T scattering functions, sometimes called linearized scattering functions, which are the correct way to define “large-signal S-parameters”) with only two distinct phases for small-signals on a frequency grid established by intermodulation frequencies and harmonics of the large-tones, with guaranteed well-conditioned data from which the X-parameter functions can be solved explicitly, without the need for regression, and not limited by performance limits of the reference generator or phase-noise.

Abstract: A measurement and correction method provides for a complete full correction of a true-mode system using only the single ended error matrix developed for 4 port correction of single ended measurements. The degree of misalignment of the balanced sources may be determined from these measurements.

Abstract: A method for eliminating the systematic measurement errors from a measurement system, for example a vector network analyzer, such that an accurate representation of the behavior of a nonlinear device can be measured or characterized. The cross-frequency phase and absolute amplitude of the measured voltage waves applied to and emanating from the nonlinear device are measured and error corrected. These waves may be used for nonlinear device characterization or modeling.

Abstract: A test system and methods using the test system correlate measurements of a device under test (DUT) regardless of which test fixture is used for in-fixture testing of the DUT. The test system includes test equipment, a test fixture that interfaces the DUT to the test equipment, a computer and a computer program executed by the computer. The computer program includes instructions that implement determining a port-specific difference array for test fixtures used with the test system. The difference array describes a difference between the test fixtures at a corresponding test port thereof. The method includes determining the difference array, measuring a performance of the DUT in a second test fixture, and applying the difference array such that the measured performance approximates a hypothetical DUT performance for the DUT as if mounted in a first test fixture.

Abstract: A method is presented where the phase trace is offset for each sweep such that the first point is always at zero degrees. The resulting traces are then averaged. The average reduces the noise in the phase trace and results in a less noisy group delay trace.

Abstract: A measurement and correction method provides for a complete full correction of a true-mode system using only the single ended error matrix developed for 4 port correction of single ended measurements. The degree of misalignment of the balanced sources may be determined from these measurements.

Abstract: A receiver channel, test system and method employ adaptive nulling to filter a targeted frequency component from a pulsed signal to produce a filtered pulsed signal. The filtered pulsed signal facilitates measuring pulsed performance parameters of a device under test. The receiver channel includes an adaptive nulling filter having a frequency response with a null that is adjustable in a null location to correspond to a vicinity of the targeted component. The test system includes a pulsed signal source, a test set, and a controller that controls the signal source and the test set. The test set includes the receiver channel with the adaptive nulling filter. The method of adaptive null filtering includes adjusting a location of a null in a frequency response of the adaptive nulling filter to correspond to a vicinity of the targeted component to produce the filtered pulsed signal.