Method and apparatus for automatic loop control

Abstract

A method of automatically controlling a loop comprising the steps of applying an input signal and an error correction signal to a signal correction circuit to provide a digital corrected signal. Applying the digital corrected signal and a reference signal to an error measurement circuit and providing a difference signal representative of the difference between the corrected signal and the reference signal. Applying the difference signal to a tri-state buffer having an output which is switchable to high impedance and passing the error correction signal to a correction circuit through an integrator and a local generator circuit. The buffer is switched to high impedance when the difference between the error correction signal and the reference signal is zero.