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:
Feb. 07, 2012
Filed:
Feb. 18, 2009
Viet Linh DO, Carlsbad, CA (US);
Philip Michael Clovis, San Diego, CA (US);
Michael Hellmer, Carlsbad, CA (US);
Mehmet Mustafa Eker, San Marcos, CA (US);
Hongming an, San Diego, CA (US);
Simon Pang, San Diego, CA (US);
Viet Linh Do, Carlsbad, CA (US);
Philip Michael Clovis, San Diego, CA (US);
Michael Hellmer, Carlsbad, CA (US);
Mehmet Mustafa Eker, San Marcos, CA (US);
Hongming An, San Diego, CA (US);
Simon Pang, San Diego, CA (US);
Applied Micro Circuits Corporation, San Diego, CA (US);
Abstract
A system and method are provided for automatic frequency acquisition maintenance in a clock and data recovery (CDR) device. In an automatic frequency acquisition (AFA) mode, the method uses a phase detector (PHD) to acquire the phase of a non-synchronous input communication signal having an initial first frequency. In the event of a loss of lock/loss of signal (LOL/LOS) signal being asserted, a frequency ratio value is retrieved from memory. Using a phase-frequency detector (PFD), the reference signal, and the frequency ratio value, a synthesized signal is generated. In response to using the PFD to generate the synthesized signal and the LOL/LOS signal being deasserted, a rotational frequency detector (RFD) is used to generate a synthesized signal having a frequency equal to the frequency of the input communication signal. With the continued deassertion of the LOL/LOS signal, the PHD is enabled and the phase of the input signal is acquired.