| 摘要 |
A method for the formation of a comparison square wave signal having a reference edge in a curve control device in which a scanning head periodically transversely scans a line to be tracked and transmits a base comparison square wave signal and a measurement square wave signal whose phase position is a criterion for the divergence of the scanning head from the desired value, and is determined by comparison with the position of the base comparison square wave signal, whereby a follow-up signal is formed which is dependent on the direction of the divergence. The method comprises forming by frequency halving, integration and threshold means, needle pulses from the base comparison square wave signal produced by the scanning head, each successive pair of the needle pulses being completely symmetrical to the reference edge and wherein the comparison square wave signal is formed from the needle pulses and the reference edge.
|
