Applied Control Theory for Embedded Systems

226 Chapter 9

There are a number of facets to measuring frequency response that must be

addressed. You must excite the system with the correct sinusoidal waveform, and

you must collect the resulting system behavior and extract the relevant frequency

response data from it. This must be done in a manner that is relatively immune

from the noise than inevitably permeates a real-world control system, that is prac-

tical and easy to use, and doesn’t add significantly to the cost of your system.

9.2 Measuring in Isolation

The most direct way to measure a system’s response at a given frequency is

accomplished by driving the system under test with ...