Invention Grant
- Patent Title: Frequency ratio detection
- Patent Title (中): 频率比检测
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Application No.: US12019171Application Date: 2008-01-24
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Publication No.: US08111800B2Publication Date: 2012-02-07
- Inventor: Philip Michael Clovis
- Applicant: Philip Michael Clovis
- Applicant Address: US CA San Diego
- Assignee: Applied Micro Circuits Corporation
- Current Assignee: Applied Micro Circuits Corporation
- Current Assignee Address: US CA San Diego
- Agency: Law Office of Gerald Maliszewski
- Agent Gerald Maliszewski
- Main IPC: H03D3/24
- IPC: H03D3/24

Abstract:
A system and method are provided for determining a frequency ratio in a phase-locked loop (PLL) circuit feedback path. The method accepts a reference signal having a predetermined first frequency and a PLL output signal having a non-predetermined second frequency. The reference signal cycles are counted, creating a first binary count. Likewise, the PLL output signal cycles are counted, creating a second binary count. The second binary count is sampled at an interval responsive to the first binary count, and a right-shifted second binary count is supplied as a ratio of the second frequency divided by the first frequency. More explicitly, the sampling is performed when a first binary count sampling threshold of 2n first frequency cycles is reached. Then, the radix point in the second binary count is shifted n number of radix places to the left.
Public/Granted literature
- US20090190707A1 Frequency Ratio Detection Public/Granted day:2009-07-30
Information query
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