Abstract: A method for measuring modulated radio frequency (RF) signals from a device under test (DUT) includes inputting a test RF signal to the DUT, where the test RF signal is modulated with a repetitive complex waveform and a pulsed waveform, the repetitive complex waveform including multiple RF tones with an RF tone spacing and an RF repetition period, where a pulse width of the pulsed waveform is less than the RF repetition period; acquiring an output RF signal from the DUT responsive to the input test RF signal; down converting the output RF signal to an intermediate frequency (IF) signal; sampling the IF signal using an analog to digital converter (ADC) having an ADC clock frequency; measuring ADC samples of the IF signal; and reconstructing the test RF signal modulated with the repetitive complex waveform using the measured ADC samples.

Abstract: A method is provided for detecting power of a periodic signal in a band of interest of the periodic signal having a predetermined bandwidth. The method includes determining frequencies of multiple tones in the periodic signal, respectively; receiving the periodic signal at a signal analyzer; selectively measuring power values at the frequencies of the multiple tones; and determining a band power of the periodic signal over the predetermined bandwidth by summing the power values at the frequencies of the multiple tones.

Abstract: A method for measuring modulated radio frequency (RF) signals from a device under test (DUT) includes inputting a test RF signal to the DUT, where the test RF signal is modulated with a repetitive complex waveform and a pulsed waveform, the repetitive complex waveform including multiple RF tones with an RF tone spacing and an RF repetition period, where a pulse width of the pulsed waveform is less than the RF repetition period; acquiring an output RF signal from the DUT responsive to the input test RF signal; down converting the output RF signal to an intermediate frequency (IF) signal; sampling the IF signal using an analog to digital converter (ADC) having an ADC clock frequency; measuring ADC samples of the IF signal; and reconstructing the test RF signal modulated with the repetitive complex waveform using the measured ADC samples.

Abstract: A method is provided for detecting power of a periodic signal in a band of interest of the periodic signal having a predetermined bandwidth. The method includes determining frequencies of multiple tones in the periodic signal, respectively; receiving the periodic signal at a signal analyzer; selectively measuring power values at the frequencies of the multiple tones; and determining a band power of the periodic signal over the predetermined bandwidth by summing the power values at the frequencies of the multiple tones.

Abstract: A system and method prevent interference caused by images resulting from mixing an incoming periodically modulated RF signal with multiple LO signals generated by a LO in a receiver system. The method includes determining tone frequencies of multiple tones and determining tone spacing between adjacent tones in the periodically modulated RF signal using a known period of modulation of the periodically modulated RF signal; identifying a sampling rate of an ADC of the receiver system; determining a DFT record size of samples provided by the ADC based on at least the tone spacing and the ADC sampling rate; and determining LO frequencies of the multiple LO signals based on at least the DFT record size and the ADC sampling rate, such that images created by respectively mixing the determined LO frequencies with portions of the periodically modulated RF signal avoid interfering with direct mixing components of the plurality of tones.

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 radio frequency (RF) measurement system acting as a spectrum analyzer and a method of operating the same eliminates image signals from a detected input RF spectrum. The method includes determining at least three local oscillator (LO) frequencies; determining LO offsets between the LO frequencies; and mixing the LO frequencies with the input RF spectrum to provide corresponding intermediate frequency (IF) signals having an IF bandwidth, where at least one of the IF signals has the input RF spectrum mixed to a different portion of the IF bandwidth than at least one other of the IF signals, providing overlapping coverage. The method further includes acquiring ADC time records for the IF signals; performing Fourier transforms (FTs) on the ADC time records to provide IF spectrums; and detecting RF responses from the IF spectrums to determine an RF response trace corresponding to the input RF 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: A radio frequency (RF) measurement system acting as a spectrum analyzer and a method of operating the same eliminates image signals from a detected input RF spectrum. The method includes determining at least three local oscillator (LO) frequencies; determining LO offsets between the LO frequencies; and mixing the LO frequencies with the input RF spectrum to provide corresponding intermediate frequency (IF) signals having an IF bandwidth, where at least one of the IF signals has the input RF spectrum mixed to a different portion of the IF bandwidth than at least one other of the IF signals, providing overlapping coverage. The method further includes acquiring ADC time records for the IF signals; performing Fourier transforms (FTs) on the ADC time records to provide IF spectrums; and detecting RF responses from the IF spectrums to determine an RF response trace corresponding to the input RF spectrum.

Abstract: An impedance tuning measurement setup and method for characterizing high frequency devices-under-test whereby one inserts an extremely low loss directive coupling structure between the terminal of the device-under-test and that part of the impedance tuner that generates the variable impedance. One or both coupled arm outputs of the directive coupling structure are connected to the inputs of a broadband RF receiver. By using the extremely low loss directive coupling structure one avoids the loss of energy caused by the distributed directional couplers or the resistive bridges used in prior art. The low loss directive coupling structure is formed by a small piece of conductive wire, which is inserted into the electro-magnetic waveguiding structure that guides the RF signals towards and from the DUT terminals. The ends of the small piece of conductive wire are connected to the center conductors of two electromagnetic waveguiding structures, which act as the coupling arms.