发明名称 Method of calibrating PLL frequency synthesizers to precise frequencies with low tolerance crystals in their master reference oscillators
摘要 A frequency tracking circuit and method comprising a master crystal oscillator circuit is used for frequency tracking between a handset and a base station comprising a calibration subsystem for taking a temperature measurement, a reference control circuit for determining a numerical value needed to align a handset frequency with a base station frequency, an adder for adding the numerical value to a previous numerical value determined by the reference control circuit, a latch for latching the output of the adder, and a low precision master crystal oscillator for clocking the frequency of the latch. The most significant bit from the latch is input into a phase/frequency detector for forcing a voltage controlled oscillator to track a desired frequency.
申请公布号 US7228118(B2) 申请公布日期 2007.06.05
申请号 US20020180027 申请日期 2002.06.27
申请人 AGERE SYSTEMS INC. 发明人 STEVENSON CARL
分类号 H04B1/06;H03L1/02;H03L7/06 主分类号 H04B1/06
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