New phase-lock loop circuit providing very fast acquisition time.

We present a new circuit configuration for second-order phase- lock loops that provides, for large initial frequency offsets, acquisition times several orders of magnitude faster than that achieved using conventional phase-lock loops. This new circuit also provides frequency locking almost instantaneously when the time delay around the loop is small. Furthermore it can, without losing lock, sustain frequency changes several hundred times faster than those which can be sustained by a conventional circuit.