Continuous delay regulator for controlling recording errors

The principle that tracing and tracking errors arise solely from delay-modulation processes has not found wide application for controlling these errors, because of device imperfections. These can be overcome by use of a regulation principle. Regulation can also be used in a switching-synthesis scheme, achieving continuous delay control without delay lines. The regulation principle invoked is that of the phase-locked loop. The switching-synthesis scheme is a sampled-data analog of the phase-locked loop. Rational design approaches are indicated.