The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 07, 2021
Filed:
Sep. 11, 2020
Apple Inc., Cupertino, CA (US);
Samed Maltabas, Santa Clara, CA (US);
Boon-Aik Ang, Los Altos, CA (US);
Yu Chen, Santa Clara, CA (US);
Dennis M. Fischette, Jr., Mountain View, CA (US);
Apple Inc., Cupertino, CA (US);
Abstract
A clock signal generated by a fractional-N phase-locked loop circuit may include deterministic jitter resulting from a sigma-delta modulation of a frequency divisor used by a divider circuit. In order to reduce such jitter, a cancelation circuit is employed that can generate a feedback signal by delaying an output signal from the divider circuit, where the amount of delay applied to the output signal is based on an accumulated phase residue from the modulation of the frequency divisor. The resultant feedback signal is compared to a reference signal, results of which are used to adjust an oscillator circuit generating the clock signal, thereby reducing the deterministic jitter.