Back to results
US 7,406,144 B2Granted
Clock generator circuit using phase modulation technology and method thereof
AssigneeRealtek Semiconductor Corp.
InventorPing-Ying Wang
Life of this patent
Estimating the term…
Abstract
A clock generator circuit, comprising: a multi-phase clock signal generator for generating a plurality of clock signals having a same frequency but difference phases according to a reference clock signal; a modulation device for generating a phase modulation signal through Delta-Sigma modulation; and a phase modulator, which is electrically coupled to the modulation device, for selecting one of the clock signals to be a modulated clock signal according to the phase modulation signal.
Claims17
A clock generating circuit, comprising:
- a clock generator for receiving a reference clock signal and thereby generating an output clock signal;
- and
- a spread spectrum control circuit, coupled to the clock generator, for generating a modulated clock signal with a frequency variation according to the output clock signal and a modulation value, comprising:
- a modulation value generating circuit for outputting the modulation value;
- and
- a frequency control circuit, coupled to the clock generator and the modulation value generating circuit, for generating the modulated clock signal according to the output clock signal and the modulation value with which an average frequency of the modulated clock signal varies;
- wherein the modulation value varies with time in a predetermined manner so as to force the average frequency of the modulated clock signal to change up and down over time, the clock generator operates in a way being independent of the spread spectrum control circuit when the average frequency of the modulated clock signal changes up and down over time, and the output clock signal generated by the clock generator and the modulated signal generated by the spread spectrum control circuit are separate signals.
4 more elements
A clock generating method, comprising:
- generating an output clock signal according to a reference clock signal;
- and
- executing a spread spectrum control step for generating a modulated clock signal with a frequency variation according to the output clock signal and a modulation value, the spread spectrum control step comprising:
- generating the modulation value;
- and
- generating the modulated clock signal according to the output clock signal and the modulation value with which an average frequency of the modulated clock signal varies;
- wherein the modulation value varies with time in a redetermined manner so as to force the average frequency of the modulated clock signal to change up and down over time, the output clock signal is generated in a way being independent of the spread spectrum control step when the average frequency of the modulated clock signal changes up and down, and the output clock signal and the modulated clock signal are separate signals.
4 more elements
Dependencies are inferred from the claim text.