| 摘要 |
<p>A timing control apparatus synchronizes the operation of logic devices to an external reference clock signal. In one aspect, the apparatus includes an oscillator (14) that generates an internal reference clock signal (16) and a phase comparator (20) that generates an error signal (20c) indicating the difference in phase and frequency between the internal (16) and external (18) clock signals. A filter (12) coupled to the comparator (20) generates plural control signals (13a,13b), each having a characteristic, e.g. a voltage amplitude, that is a selected function of the error signal (20c). The control signals (13a,13b) are routed to the oscillator (14), which generates the internal reference clock signal (16) as a function of those control signals (13a,13b).</p> |
