Abstract: Testing devices such as integrated circuits (IC) with integrated antennas configured for millimeter wave (mmW) transmission and/or reception. A DUT may be mounted to an interface in a measurement fixture (e.g., a socket, anechoic chamber, etc.). Power and data connections of the DUT may be tested over the interface, which may also provide connections (e.g., wired) for input/output signals, power, and control and may also provide positioning. Radio frequency (RF) characteristics of the DUT may be tested over-the-air using an array of antennas or probes in the radiating Fresnel zone of the DUT's antennas. Each of the antennas or probes of the array may incorporate a power detector (e.g., a diode) so that the RF radiating pattern may be measured using DC voltage measurements. Measured voltage measurements may be compared to an ideal signature, e.g., voltage measurements expected from an ideal or model DUT.

Abstract: Various embodiments are presented of a system and method for testing (e.g., rapidly and cheaply) devices with antennas configured for radio frequency (RF) and/or millimeter wave (mmW) transmission and/or reception. A device to be tested (e.g., the device under test (DUT)) may be mounted to an interface in a measurement fixture (e.g., a socket, anechoic chamber, etc.). Power and data connections of the DUT may be tested over the interface, which may also provide connections for input/output signals, power, and control and may also provide positioning. RF characteristics (e.g., including transmission, reception, and/or beamforming) of the DUT may be tested over-the-air using an array of antennas or probes.

Abstract: Various embodiments are presented of a system and method for testing (e.g., rapidly and cheaply) devices with antennas configured for radio frequency (RF) and/or millimeter wave (mmW) transmission and/or reception. A device to be tested (e.g., the device under test (DUT)) may be mounted to an interface in a measurement fixture (e.g., a socket, anechoic chamber, etc.). Power and data connections of the DUT may be tested over the interface, which may also provide connections for input/output signals, power, and control and may also provide positioning. RF characteristics (e.g., including transmission, reception, and/or beamforming) of the DUT may be tested over-the-air using an array of antennas or probes.

Abstract: Testing devices such as integrated circuits (IC) with integrated antennas configured for millimeter wave (mmW) transmission and/or reception. A DUT may be mounted to an interface in a measurement fixture (e.g., a socket, anechoic chamber, etc.). Power and data connections of the DUT may be tested over the interface, which may also provide connections (e.g., wired) for input/output signals, power, and control and may also provide positioning. Radio frequency (RF) characteristics of the DUT may be tested over-the-air using an array of antennas or probes in the radiating Fresnel zone of the DUT's antennas. Each of the antennas or probes of the array may incorporate a power detector (e.g., a diode) so that the RF radiating pattern may be measured using DC voltage measurements. Measured voltage measurements may be compared to an ideal signature, e.g., voltage measurements expected from an ideal or model DUT.

Abstract: A test and measurement instrument including a time domain channel configured to process a first input signal for analysis in a time domain; a frequency domain channel configured to process a second input signal for analysis in a frequency domain; and an acquisition system coupled to the time domain channel and the frequency domain channel. The acquisition system is configured to acquire data from the time domain channel and the frequency domain channel. Time domain and frequency domain data can be time aligned.

Abstract: A test and measurement instrument including a time domain channel configured to process a first input signal for analysis in a time domain; a frequency domain channel configured to process a second input signal for analysis in a frequency domain; and an acquisition system coupled to the time domain channel and the frequency domain channel. The acquisition system is configured to acquire data from the time domain channel and the frequency domain channel. Time domain and frequency domain data can be time aligned.

Abstract: A method and apparatus for improved video bandwidth resolution in DFT-based spectrum analysis is disclosed. A first embodiment comprises an emulation of a continuous range of video bandwidths in DFT-based spectrum analysis using overlapping resolution bandwidth frames. A second embodiment utilizes frame weighting to reduce the standard deviation in the spectrum of noise signal to emulate a corresponding standard deviation of a specified video bandwidth.

Abstract: A modulation domain trigger generator demodulates a modulated input signal to extract information content, and a trigger is generated from the extracted information content in response to specified trigger criteria. The modulation domain trigger generator may be combined with a plurality of different types of trigger generators, including frequency domain and time domain trigger generators, to process the input signal in response to different trigger criteria to produce more than one trigger. The different trigger outputs may be combined to produce an acquisition trigger to acquire data surrounding an anomalous or identifiable event within the input signal.

Abstract: A filter equalization technique for an analog signal path, such as in an instrument that simultaneously measures a signal over a band of frequencies, uses magnitude measurement data for high frequency bands for which phase-calibrated sources are not readily available. A sinusoidal signal source together with an accurate power meter is used to provide a stepped frequency input over a desired frequency band to the analog signal path with an accurate measured magnitude. The output of the analog signal path is digitized and the resulting frequency magnitudes are computed. Then the resulting power meter results are deducted from the frequency magnitudes measured each time by the instrument to determine the magnitude response of the analog signal path. Using a Hilbert transform the corresponding phase response is determined based on a minimum phase assumption over the desired frequency band. From the magnitude and phase responses an inverse or digital equalization filter may be designed for the analog signal path.

Abstract: A method and apparatus for improved video bandwidth resolution in DFT-based spectrum analysis is disclosed. A first embodiment comprises an emulation of a continuous range of video bandwidths in DFT-based spectrum analysis using overlapping resolution bandwidth frames. A second embodiment utilizes frame weighting to reduce the standard deviation in the spectrum of noise signal to emulate a corresponding standard deviation of a specified video bandwidth.

Abstract: A method for measuring two or more input signals using a single-input measuring device is described. Test equipment that comprises a single-input measuring device is provided. A first input is received. A second input is received. The second input is delayed by a time delay T to provide a delayed second input. The first input and the delayed second input are combined to provide a combined input signal. The combined input signal is provided to the test equipment.

Abstract: A selected length of antenna for a device under test is placed within a conductive inner cylinder, forming an unterminated “input” coaxial transmission line. The inner cylinder is in turn within and coaxial with a conductive outer cylinder, forming an “output” transmission line. The inner cylinder is the center conductor of the output transmission line, and in a region extending beyond the extent of the antenna therein, conically tapers to being a normal center conductor of solid cross section. The outer cylinder matches this taper to maintain a constant characteristic impedance Z0out (say, 50 &OHgr;) for the output transmission line, which then delivers its output signal to a matched terminating load in measurement equipment via either a coaxial connector or an interconnecting length of auxiliary transmission line.

Abstract: An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision.

Abstract: An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision.

Abstract: A method of providing DC coupled frequency modulation without center frequency offset of a RF carrier frequency generated in a phase-locked loop circuit. The circuit is automatically calibrated to generate a feedback signal for cancelling DC offsets at the input of the coupling integrator with a digital-to-analog converter and resistor network driven by a digital counter. After removing frequency modulation, the coupling integrator's output will ramp while the offsets remain uncancelled. Incrementing or decrementing the digital counter in response to the integrator's output will adjust the feedback signal until the offsets are cancelled and the integrator ceases to ramp. The counter value is stored in a memory to allow subsequent presetting of the feedback signal to the calibrated magnitude. Holding the feedback signal constant thereafter during DC coupled frequency modulation keeps the RF carrier at center frequency.

Abstract: A vector locked loop is disclosed having a topology somewhat similar to two cross coupled phase locked loops, but wherein both magnitude and phase are used as feedback signals. The output signal is generated by combining the outputs of two VCOs in a combiner network. This output signal is fed back to the input, where phase and magnitude detectors are used to generate error signals. These error signals are processed to yield control signals for controlling the frequencies of the two VCOs. The vector locked loop can be adapted for a number of applications, including frequency translation, modulation (phase, amplitude or arbitrary), and high efficiency linear power amplification.

Abstract: Vector modulation is effected by summing output signals from two phase modulators. The lack of amplitude modulation on the signals when summed permits non-linear processing of the signals, such as PLL frequency translation. In one embodiment, the phase modulators comprise fractional-N phase locked loops modulated with digital data words. In another, the phase modulators comprise direct digital synthesizers.

Abstract: A multi-path, ladder-type variable step RF signal attenuator is provided. The ladder network is comprised of a number of asymmetric power splitting elements and PI-pad resistor attenuator elements. The high-speed switching and long life characteristics of PIN diodes are utilized to switch resistive attenuator elements into or out of the ladder network to provide selectable values of signal attenuation.

Abstract: Apparatus is provided to frequency modulate (FM) RF carrier frequencies generated in a phase-locked loop (PLL). FM outside the loop bandwidth is AC coupled to the loop. FM within the loop bandwidth is DC coupled via an integrating OP-AMP to provide phase modulation. Whenever the output of the integrator exceeds a preset threshold, a prescaler removes or adds two pi (or integral multiples of two pi) radians of phase change from the input to the loop divide-by-N circuit. At the same time, a current source pumps charge into the integrator to exactly compensate for the amount of phase removed or added resetting the integrator. DC feedback around the integrating OP-AMP and a feedback signal proportional to the exact amount of phase added or removed provides a true synthesized loop center frequency with no drift. When the feedback path is interrupted, DC FM is provided.