METHOD AND DEVICE FOR PERFORMING CLOCK COMBINATION BY USING UNIVERSAL SERIAL BUS DOWNSTREAM RECEPTION SIGNAL

摘要

PROBLEM TO BE SOLVED: To generate a reference clock by using a downstream reception USB signal transmitted by a host computer or a hub.

SOLUTION: A USB device having a free-running oscillator generates a local clock signal in response to a signal on a universal serial bus (USB). The oscillator is substantially stable and operates at a frequency known for substantial incorrectness. A single end bit serial signal is extracted from a reception signal transmitted by a USB host computer or a hub, and a timing signal is activated by responding to it. A bit pattern is detected and intervals are measured in the single end bit serial signal, and the timing signal is activated in that period. A period P of the local clock signal is adjusted in response to one of the measured intervals.

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