Glossary of Control Engineering Terms - Q

Quantisation: Digital computers operate with finite arithmetic. When a signal is sampled it is converted to a binary value with a finite number of bits so some bits must be truncated or rounded off.

Quantitative Feedback Theory (QFT): A robust control design technique where the plant uncertainty is represented by a set of templates in the complex plain (polar form) within each is enclosed all possible frequency responses for some specified frequency. The uncertainty templates are usually generated by a discrete grid of uncertainty parameters. From these templates performance constraints can be generated such that the controller can be designed in the complex plain or Nichols chart.