由于有锁频环的频率牵引，锁相环路滤波器可以设计得很窄，具有很好的抑噪性能，满足精确跟踪载波相位的要求。
Due to the frequency pulling of FLL, the passband of the filter in PLL can be made very narrow to suppress the noise, and the PLL can lock carrier's phase with high accuracy.
本文提出一种简单的跟踪滤波器电路，该电路可用于多普勒雷达，主要由开关式带通滤波器和锁相环组成。
This paper presents a simple tracking filter circuit, which is applicable to Doppler radar sets and consists mainly of a switched bandpass filter and a phase-locked loop.
描述了基于AT89C52单片机、锁相环和开关电容滤波器的正交信号发生器的设计和实现方法。
The design and implementation of quadrature waveform generator are described based on the AT89C52, phase-locked loop(PLL) and switched-capacitor filter(SCF).
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