Evolution
Analog frequency correction

The advent of microcomputing has led to the development of a large number of CAD programs that can automatically plot frequency curves and associated time responses. What's more, these programs can optimize parameter settings to achieve the best possible performance. Mathlab is one example in the English-speaking world, and Sirena (IUT de Nantes) in France, for teaching purposes.

In terms of hardware, almost all correctors are moving towards all-digital technology. Sampling periods and calculation times are short enough to ensure that the digital aspect remains "transparent" to the user.

So, while the analysis and understanding of the servo system's operation remains in the frequency domain, implementation is increasingly taking place in digital form.