Abstract: An apparatus can include a display, a facial interface, and a connector between the display and the facial interface. The facial interface can at least translate or rotate relative to the display via the connector.

Abstract: A method is provided for calibrating a test system, including first and second test instruments. The method includes connecting a first test port of the first test instrument to a second test port of the second test instrument; generating a first RF signal using a first RF source of the first test instrument while a second RF source of the second test instrument is turned off; measuring first phase of the first RF signal at the first test port using first incident and reflected signals; generating a second RF signal using a second RF source of the second test instrument while the first RF source; measuring second phase of the second RF signal at the first test port using the second incident signal and reflected signals; determining a phase difference between the first and second phases; and adjusting the first and/or second RF source to remove the determined phase difference.

Abstract: A method is provided for calibrating a test system, including first and second test instruments. The method includes connecting a first test port of the first test instrument to a second test port of the second test instrument; generating a first RF signal using a first RF source of the first test instrument while a second RF source of the second test instrument is turned off; measuring first phase of the first RF signal at the first test port using first incident and reflected signals; generating a second RF signal using a second RF source of the second test instrument while the first RF source; measuring second phase of the second RF signal at the first test port using the second incident signal and reflected signals; determining a phase difference between the first and second phases; and adjusting the first and/or second RF source to remove the determined phase difference.

Abstract: A method is provided for calibrating a test system, including an RF source combined with a VNA connected to or embedded in a test instrument. The method includes connecting to a power meter at the test port; generating an RF signal at an RF source as an incident signal, and providing the incident signal to the power meter through the test port; measuring a forward power wave of the incident signal using a first receiver; measuring a reverse power wave of a reflected signal using a second receiver; measuring output power at the test port using the power meter; and calculating magnitude errors of the first receiver and the second receiver using the measured forward power wave, the measured reverse power wave, and the measured output power by the power meter, and determining magnitude error correction terms of the forward and reverse power waves to remove the magnitude errors.

Abstract: A test instrument, including an embedded VNA circuit, for testing a DUT. The test instrument includes a first receiver for receiving an incident RF signal through a first coupling device; a second receiver for receiving a reflected RF signal through a second coupling device; a test port for connecting to an interconnect, which is connectable to a calibration device in a calibrating stage, during which the interconnect is characterized, and to the DUT in a testing stage, during which at least one parameter of the DUT is tested; an RF source for generating the incident RF signal during the calibrating stage; and a processing unit programmed to determine S-parameters of the interconnect based on the incident RF signal and the reflected RF signal, the S-parameters compensating for error introduced by the interconnect when testing the at least one parameter of the DUT in the testing stage.

Abstract: Nonlinear distortion of a device under test (DUT) is detected by obtaining measurements of a multi-tone input signal from a signal generator to a DUT, to obtain a measured multi-tone input signal. Measurements are also obtained of a multi-tone output signal from the DUT that is generated based on the multi-tone input signal, to obtain a measured multi-tone output signal. A correlated part of the measured multi-tone output signal that is correlated with the measured multi-tone input signal is determined insofar as the correlated part corresponds to a frequency response function of the DUT.

Abstract: A method is provided for calibrating a test system, including an RF source combined with a VNA connected to or embedded in a test instrument. The method includes connecting to a power meter at the test port; generating an RF signal at an RF source as an incident signal, and providing the incident signal to the power meter through the test port; measuring a forward power wave of the incident signal using a first receiver; measuring a reverse power wave of a reflected signal using a second receiver; measuring output power at the test port using the power meter; and calculating magnitude errors of the first receiver and the second receiver using the measured forward power wave, the measured reverse power wave, and the measured output power by the power meter, and determining magnitude error correction terms of the forward and reverse power waves to remove the magnitude errors.

Abstract: A test instrument, including an embedded VNA circuit, for testing a DUT. The test instrument includes a first receiver for receiving an incident RF signal through a first coupling device; a second receiver for receiving a reflected RF signal through a second coupling device; a test port for connecting to an interconnect, which is connectable to a calibration device in a calibrating stage, during which the interconnect is characterized, and to the DUT in a testing stage, during which at least one parameter of the DUT is tested; an RF source for generating the incident RF signal during the calibrating stage; and a processing unit programmed to determine S-parameters of the interconnect based on the incident RF signal and the reflected RF signal, the S-parameters compensating for error introduced by the interconnect when testing the at least one parameter of the DUT in the testing stage.

Abstract: Nonlinear distortion of a device under test (DUT) is detected by obtaining measurements of a multi-tone input signal from a signal generator to a DUT, to obtain a measured multi-tone input signal. Measurements are also obtained of a multi-tone output signal from the DUT that is generated based on the multi-tone input signal, to obtain a measured multi-tone output signal. A correlated part of the measured multi-tone output signal that is correlated with the measured multi-tone input signal is determined insofar as the correlated part corresponds to a frequency response function of the DUT.

Abstract: A receiver and method for using the same to generate phase spectra that are independent of the starting time of the sequence of digital measurements used to generate the phase spectra are disclosed. The receiver includes a first signal port adapted to receive a first test signal that includes a plurality of tones and a first ADC that generates one digital value from the first test signal in response to each clock pulse from an ADC clock. The first receiver also includes a phase clock register that includes a time stamp value that is incremented on each clock pulse from the ADC clock, and a processor that records a sequence of the digital values starting at a first time and the time stamp value at the first time.

Abstract: A method for calibrating a mixer, an apparatus using the calibrated mixer, and a method for using the apparatus to calibrate another mixer are disclosed. The method includes coupling a first RF signal characterized by a first timezero phase and a first RF frequency to the RF signal input. The method includes (a) coupling a first LO signal characterized by a first LO frequency and a first LO timezero phase to the LO signal input terminal; (b) determining an IF tone timezero phase of a tone from the IF signal output corresponding to the first LO signal; and (c) determining a first after LO signal path timezero phase from the IF tone and first LO timezero phase. Steps (a), (b), and (c) are repeated for second and third LO signals. An LO phase change as a function of frequency introduced by the LO signal path is then determined.

Abstract: Network analysis employs a band-limited multi-tone test signal having a tunable center frequency to test a device under test (DUT). A hybrid network analyzer includes a test signal source to provide the band-limited multi-tone test signal, and a local oscillator (LO) source to provide a tunable LO signal configured to track the tunable center frequency of the band-limited multi-tone test signal. The hybrid network analyzer further includes a receiver to convert into an intermediate frequency (IF) signal using the tunable LO signal one or both of the band-limited multi-tone test signal and a response signal from a device under test (DUT) produced in response to the band-limited multi-tone test signal. The test signal source is further configured to provide a tunable single-tone test signal and a broadband multi-tone test signal to test the DUT in various modes.

Abstract: A system and method sequentially measure the amplitude and phase of an output signal of a device under test in each of two or more frequency ranges which together span the output signal spectrum, using a local oscillator (LO) signal whose frequency changes for each measurement. The measured phase of the output signal is adjusted for at least one of the frequency ranges to account for a change of phase in the LO signal from measurement of one frequency range to another frequency range, including applying to the measured phase a phase offset determined by measuring the phase of a pilot tone using the LO signal before and after the frequency of the LO signal changes from measurement of one frequency range to another. The phase-adjusted measurements of the output signal in the two or more frequency ranges are stitched together to determine the amplitude and phase of the output signal across the output signal spectrum.

Abstract: An apparatus, a signal source, and a method for operating the same are disclosed. The apparatus includes a first signal source, a port, controller, signal synthesizer, and a first timestamp register. The port is adapted to receive a first clock signal that includes a sequence of pulses at a constant clock frequency. The signal synthesizer generates an output signal in response to inputs from the controller, the output signal having a first frequency. The first timestamp register counts pulses from the first clock signal. The controller is adapted to receive a command to change the output signal frequency from the first frequency to a second frequency, the controller causing the signal synthesizer to change the output signal frequency to the second frequency and to generate a frequency change timestamp from the timestamp register indicating a time at which the output signal changed from the first frequency to the second frequency.

Abstract: Network analysis employs a band-limited multi-tone test signal having a tunable center frequency to test a device under test (DUT). A hybrid network analyzer includes a test signal source to provide the band-limited multi-tone test signal, and a local oscillator (LO) source to provide a tunable LO signal configured to track the tunable center frequency of the band-limited multi-tone test signal. The hybrid network analyzer further includes a receiver to convert into an intermediate frequency (IF) signal using the tunable LO signal one or both of the band-limited multi-tone test signal and a response signal from a device under test (DUT) produced in response to the band-limited multi-tone test signal. The test signal source is further configured to provide a tunable single-tone test signal and a broadband multi-tone test signal to test the DUT in various modes.

Abstract: A system and method sequentially measure the amplitude and phase of an output signal of a device under test in each of two or more frequency ranges which together span the output signal spectrum, using a local oscillator (LO) signal whose frequency changes for each measurement. The measured phase of the output signal is adjusted for at least one of the frequency ranges to account for a change of phase in the LO signal from measurement of one frequency range to another frequency range, including applying to the measured phase a phase offset determined by measuring the phase of a pilot tone using the LO signal before and after the frequency of the LO signal changes from measurement of one frequency range to another. The phase-adjusted measurements of the output signal in the two or more frequency ranges are stitched together to determine the amplitude and phase of the output signal across the output signal spectrum.

Abstract: A system and method supply a test signal having a first tone at a first RF frequency and a second tone at a second RF frequency to a frequency converter; provide a local oscillator (LO) signal to the frequency converter, wherein an IF output signal of the frequency converter is supplied to an input of an intermediate frequency (IF) filter, in response to which the IF filter provides a filtered IF output signal; for each of N>1 different LO frequencies, measure the filtered IF output signal at a pair of IF frequencies corresponding to differences between the first and second RF frequencies and the LO frequency, where the measurements of the filtered IF output signal measure time-invariant phase; and ascertain N?1 values of phase dispersion D of the IF filter at N?1 corresponding IF frequencies from the N measurements of the filtered IF output signal at the N different LO frequencies.

Abstract: A method and apparatus for generating a normalized phase spectrum from a signal having a plurality of tones is disclosed. The apparatus includes a first receiver having a first signal port adapted to receive a first test signal having a first plurality of tones and a reference port adapted to receive a phase slope reference signal includes a reference tone and generates a sequence of digital values therefrom starting from a first time. The apparatus also includes a signal digitizer that digitizes the received first test signal to generate a sequence of digitized values of the received first test signal starting at the first time and a phase spectrum generator that generates a first normalized phase spectrum that is independent of the first time from the digitized values of the received first test signal and the received phase slope reference signal.

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.