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US 2004/0017261 A1Published application
Input jitter attenuation in a phase-locked loop
AssigneeIntel Corporation
InventorsKrishnamurhty Soumyanath, Ashoke Ravi
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Abstract
To attenuate the effects of phase noise and input jitter introduced in the reference frequency of the PLL, the zeros of the forward path transfer function are removed. As a result, the forward path does not amplify any phase noise or input jitter appearing in the reference frequency. However, overall loop stability is maintained by placing the zeros in the feedback path of the PLL. A discriminator may be placed in the feedback path to introduce the zero in the loop gain transfer function and provide stability.
Claims28
A phased-locked loop (PLL) comprising:
- a comparator configured to compare a reference signal and a feedback signal and to generate an error signal;
- a filter configured to output a voltage based on the error signal;
- a voltage controlled oscillator (VCO) configured to generate a frequency based on the filter output voltage;
- and
- a feedback path configured to generate the feedback signal as a function of the VCO output frequency and to introduce a zero in a loop gain transfer function of the PLL.
2 more elements
A phase-locked loop (PLL) comprising:
- a forward path configured to output a first frequency;
- and
- a feedback path configured to output a second frequency based on the first frequency and to introduce a zero in the loop gain transfer function of the PLL.
A method comprising:
- outputting a first frequency a forward path of a phase-locked loop (PLL);
- outputting a second frequency based on the first frequency in a feedback path of the PLL;
- and
- introducing in the feedback path of the PLL a zero in the loop gain transfer function of the PLL.
1 more element
Dependencies are inferred from the claim text.