Using continuous sweep frequencies in a system frequency response test

摘要

A system and method for measuring the frequency response of a system under test using a single swept-frequency chirp signal. A tapered chirp-frequency test signal is created with a bandwidth defined by first and second frequencies. The test signal is routed to a calibration path, and the output of the calibration path is routed to a digitizer. The output of the calibration path is digitized, and a Fourier transform of the calibration path output is generated. The test signal is then routed to a test system, and the output of the test system is coupled to the digitizer. The output of the test system is digitized, and a Fourier transform of the test system output is generated. A normalized frequency-domain representation of the test system created by dividing the Fourier transform of the test system output by the Fourier transform of the calibration path output.

主权项

1. A system, comprising:
a waveform generator adapted to produce a chirp frequency signal having a continuous change over a defined range; a multiplexer coupled to an output of the chirp frequency generator, the multiplexer selectively routing the chirp frequency signal to a system under test or to a calibration path; a digitizer receiving an output from the system under test or an output from the calibration path, the digitizer configured to create data points either from the system under test or from the calibration path; and a fast Fourier transform circuit adapted to receive the data points from the digitizer and to compute the discrete Fourier transform for the data points.