Fast digital frequency response measurement with multifrequency signals
Abstract
A frequency response measurement can be achieved by applying a multifrequency signal to the unknown system and by analyzing the output signal, using the fast Fourier transform (FFT). The complex frequency response is measured simultaneously at many frequency points. Compared with the conventional method, using single sinusoidal test signals, this procedure is very fast. The reason for this is that a transient response has to decay only once before the data of the total measurement are taken. If the system is implemented digitally with fixed point arithmetic, the output is disturbed by quantization noise. A careful design of the test signal is necessary to obtain a sufficient signal to noise ratio. Test signals are proposed considering the requirements due to finite data wordlength. Modifications of the basic procedure allowing a high resolution narrowband analysis are discussed. Experimental verification is given by computer simulation.
 Publication:

Archiv Elektronik und Uebertragungstechnik
 Pub Date:
 May 1980
 Bibcode:
 1980ArElU..34..190V
 Keywords:

 Communication Theory;
 Digital Data;
 Frequency Response;
 Signal Analysis;
 Bandpass Filters;
 Bandwidth;
 Chirp Signals;
 Fast Fourier Transformations;
 High Resolution;
 Transient Response;
 Communications and Radar