摘要:
An improved interpolation technique for reconstructing a complex signal from sampled data estimates a carrier phase for each sampled data time. The carrier phase is then used to compensate for frequency variation in the complex signal. The complex components of the sampled data are then interpolated separately with the interpolated results being used to produce an interpolated magnitude that is the reconstructed complex signal.
摘要:
A trigger generator and trigger method are provided for determining whether or not a signal under test matches a modulation signature. The modulation signature may be provided as a magnitude signature, a phase signature or both. When the magnitude values, phase values, or both of a signal under test are the same as their respective modulation signature, an error computation will be close to zero. If this value is within a threshold value, a trigger signal or other indication of a match is produced.
摘要:
Testing is performed on a device under test. A first port of a first calibration module is connected to the device under test. A second port of the first calibration module is connected to a network analyzer. A first port of a second calibration module is connected to the device under test. A second port of the second calibration module is connected to the network analyzer. A measurement calibration and testing are performed without disconnecting the first port and the second port of the first calibration module and without disconnecting the first port and the second port of the second calibration module.
摘要:
An enhanced impulse response measurement for a pulsed frequency modulation (FM) radar signal provides a more accurate measurement of the amplitude of a secondary response relative to the amplitude of a main response. The pulsed FM radar signal is sampled to produce a time-domain sample record. The sample record is windowed to produce a windowed sample record. The windowed sample record is transformed into a frequency-domain spectrum. The spectrum is multiplied with the complex conjugate of a frequency-domain estimate of a transmitted pulsed FM radar signal to produce a de-spreaded pulse. The de-spreaded pulse is transformed into the time domain to produce a measurement of the impulse response having a main response and a secondary response. The amplitude of the secondary response is corrected to eliminate errors caused by the windowing.
摘要:
An electronic calibration circuit for calibrating a network analyzer. The electronic calibration circuit comprises at least one port for coupling the electronic calibration circuit to the network analyzer. A plurality of switching circuits coupled to the port are operable to provide a plurality of impedance states for electronically calibrating the network analyzer, wherein a transmission line couples at least two of the plurality of switching circuits, the transmission line short enough to reduce interactions of impedance mismatches and to reduce transmission loss. The port and the plurality of switching circuits are comprised within an integrated circuit having a package size small enough to avoid cavity resonance at a high frequency.
摘要:
A method of measuring the phase transient response of a device under test automatically provides a flattened phase transient response without any user intervention. The method comprises the steps of calculating an instantaneous phase waveform based on an instantaneous voltage waveform that represents an output signal of the device under test as it steps from a first frequency to a second frequency, calculating an instantaneous frequency waveform based on the instantaneous phase waveform, automatically estimating the second frequency based on the instantaneous frequency waveform without any user intervention, and flattening the instantaneous phase waveform based on the estimate of the second frequency.
摘要:
Noise power is measured within one or more designated frequency bands of an applied signal. The measurement includes frequency translating the applied signal by a set of equally spaced frequencies to form a corresponding set of intermediate frequency signals, measuring the noise in at least two measurement bands of each of the intermediate frequency signals that are separated by the frequency spacing of the equally spaced frequencies, and determining the noise power in the designated frequency band of the applied signal based on the noise measurements.
摘要:
A two stage adaptive filter for use in a batch receiver includes an equalizer filter having as inputs an acquired signal representing a batch of data points and an equalizer filter value. The filtered signal is batch processed to produce reference and data symbols, which symbols are input to a residual filter to generate iteratively over the batch an error value. The error value is convolved with the equalizer filter value to produce a new equalizer filter value for use by the equalizer filter when a next batch of data points is processed.
摘要:
An enhanced impulse response measurement for a pulsed frequency modulation (FM) radar signal provides a more accurate measurement of the amplitude of a secondary response relative to the amplitude of a main response. The pulsed FM radar signal is sampled to produce a time-domain sample record. The sample record is windowed to produce a windowed sample record. The windowed sample record is transformed into a frequency-domain spectrum. The spectrum is multiplied with the complex conjugate of a frequency-domain estimate of a transmitted pulsed FM radar signal to produce a de-spreaded pulse. The de-spreaded pulse is transformed into the time domain to produce a measurement of the impulse response having a main response and a secondary response. The amplitude of the secondary response is corrected to eliminate errors caused by the windowing.
摘要:
An improved interpolation technique for reconstructing a complex signal from sampled data estimates a carrier phase for each sampled data time. The carrier phase is then used to compensate for frequency variation in the complex signal. The complex components of the sampled data are then interpolated separately with the interpolated results being used to produce an interpolated magnitude that is the reconstructed complex signal.