Aspects of the frequency response testing of simple sampled systems†
J.O. Flower, G. P. WINBETT, S.C. Forge · International Journal of Control · 1971
The difficulties associated with identifying sampled-data systems using continuous frequency response techniques are examined. It is shown how, without taking certain precautions, gain and phase measurements vary in a random manner. This measurement scatter can be eliminated if certain synchronization techniques between the sampler and the start of the measurement are incorporated. Consideration of the mode of operation of the transfer function analyser in interpretation of the measured results is vitally important. The effect of variation of the sampling period as a function of the output is also investigated.