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 shorter than those 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.