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:
Apr. 29, 2014
Filed:
May. 15, 2012
Eric Naviasky, Ellicott City, MD (US);
Chris Moscone, Cary, NC (US);
Rajagopal Vijayaraghavan, Cary, NC (US);
Benjamin Louis Heilmann, Raleigh, NC (US);
Eric Naviasky, Ellicott City, MD (US);
Chris Moscone, Cary, NC (US);
Rajagopal Vijayaraghavan, Cary, NC (US);
Benjamin Louis Heilmann, Raleigh, NC (US);
Cadence Design Systems, Inc., San Jose, CA (US);
Abstract
A system and method are provided for combined generation of I and Q signal references according to a periodic input signal and selective phase interpolation of an output signal with reference thereto. A ring oscillator portion generates an oscillator signal, and includes a plurality of delay stages interconnected in cascade to collectively execute an odd number of signal state inversions within a closed loop. The delay stages establish at respective nodes defined therebetween correspondingly delayed oscillator signal versions, successively shifted in phase by a predetermined phase difference. A signal injection portion selectively applies to at least one node of the ring oscillator portion a current bias according to the periodic input signal, and selectively adjusts each current bias in amplitude. The oscillator signal is thereby frequency locked to the periodic input signal, defining I/Q references with respect to the delayed oscillator signal version established at the current biased node.