| 摘要 |
A device for the regeneration of a clock signal uses a reference clock signal given by an internal oscillator to measure the number of reference clock pulses between the first two synchronization pulses sent by an external serial bus or USB at the beginning of each transaction. Thus a rough measurement N is obtained of the USB clock signal to be regenerated. The delay of each of these two synchronization pulses with respect to the previous pulse of the reference clock signal is measured. This delay is computed with respect to an internally defined time unit. On the basis of the measurement of these two delays, and the measurement of the number of reference clock periods, and knowing the measurement n of the period of the reference clock signal in the time unit, the period of the USB clock signal to be regenerated is computed with precision.
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