发明名称 |
METHODS OF AUTOMATICALLY CALIBRATING FREQUENCY FEATURES OF A PHASE LOCKED LOOP, AND PHASE LOCKED LOOPS INCLUDING AN OPEN-LOOP AUTOMATIC FREQUENCY CALIBRATION CIRCUIT |
摘要 |
A PLL includes an open-loop automatic frequency calibration circuit. The open-loop automatic frequency calibration circuit includes a frequency detector, first and second sinks, a comparator and a bank selector. The frequency detector generates an up-signal and a down-signal responding to a frequency difference between a first phase difference signal having a phase difference from a reference oscillation signal and the second phase difference signal having a phase difference from a frequency division oscillation signal. The first and second sinks discharge the first and second capacitors respectively responding to the up-signal and the down-signal. The comparator compares voltages of the first and second capacitors. The bank selector selects a bank according to binary search, selects an optimum bank among two banks lastly searched, and outputs a bank selection signal. The voltage-controlled oscillation changes frequency features thereof in response to the bank selection signal.
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申请公布号 |
US2007264951(A1) |
申请公布日期 |
2007.11.15 |
申请号 |
US20070745654 |
申请日期 |
2007.05.08 |
申请人 |
CHO SEONG-HWAN;KIM KYUNG-LOK;LEE JUNG-HYUP;LEE JOON-HEE |
发明人 |
CHO SEONG-HWAN;KIM KYUNG-LOK;LEE JUNG-HYUP;LEE JOON-HEE |
分类号 |
H04B1/18 |
主分类号 |
H04B1/18 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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