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:
Jan. 10, 2012
Filed:
Dec. 03, 2008
Mehmet Mustafa Eker, San Marcos, CA (US);
Simon Pang, San Diego, CA (US);
Viet Linh DO, Carlsbad, CA (US);
Hongming an, San Diego, CA (US);
Philip Michael Clovis, San Diego, CA (US);
Mehmet Mustafa Eker, San Marcos, CA (US);
Simon Pang, San Diego, CA (US);
Viet Linh Do, Carlsbad, CA (US);
Hongming An, San Diego, CA (US);
Philip Michael Clovis, San Diego, CA (US);
Applied Micro Circuits Corporation, San Diego, CA (US);
Abstract
A system and method are provided for holding the frequency of a non-synchronous communication signal in a clock and data recovery (CDR) device frequency synthesizer. The method initially acquires the phase of a non-synchronous first communication signal having a first frequency, and divides a first synthesized signal by a selected frequency ratio value, creating a frequency detection signal having a frequency equal to a reference signal frequency. In response to losing the first communication signal and subsequently receiving a second communication signal with a non-predetermined second frequency, the frequency ratio value is retrieved from memory based upon the assumption that the second frequency is the same, or close to the first frequency. Using a phase-frequency detector (PFD), the reference signal, and the frequency ratio value, a second synthesized signal is generated having an output frequency equal to first frequency. Using a rotational frequency detector (RFD), the second communication signal, and the second synthesized signal, a second synthesized signal is generated having an output frequency equal to second frequency.