Patent ID: 6486650
Filing Date: 2002-11-26
Classification: H03L,H04L

Abstract:
A method for testing a communication circuit having a clock recovery circuit, the method comprising:a) applying power to the clock recovery circuit; and b) initializing a voltage controlled oscillator to near an expected operating frequency upon power up of the clock recovery circuit by: supplying a precharge signal from an external tester to a charge pump, the precharge signal being selectively supplied to the charge pump via a selector, the selector also selectively supplying a frequency error signal from frequency lock circuitry and a phase correction signal from phase lock circuitry to the charge pump, the charge pump being connected to the voltage controlled oscillator to supply a drive signal to drive the voltage controlled oscillator based on the supplied signal from the selector; wherein the precharge signal supplies a predetermined number of up pulses to the charge pump to more quickly drive the voltage controlled oscillator to near the expected operating frequency.