Invention Grant
US6167245A Method and apparatus for operating a PLL with a phase detector/sample hold circuit for synthesizing high-frequency signals for wireless communications 失效
用于使用用于合成用于无线通信的高频信号的相位检测器/采样保持电路来操作PLL的方法和装置

Method and apparatus for operating a PLL with a phase detector/sample
hold circuit for synthesizing high-frequency signals for wireless
communications
Abstract:
A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may include an analog control loop in which a phase detector circuit and sample and hold circuit are utilized. The output of the sample and hold circuit may be provided to the PLL VCO as VCO input control signals.
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