Title：Circuit system and control method for directly demodulating frequency modulated signal based on phase-locked loop
Country：China
Patent No.：201811150180.6
Legal Status：Under review
Inventor：Woogeun Rhee, Yining Zhang, Ranran Zhou, Zhihua Wang
Assignee：Tsinghua University
Address：Tsinghua University,Haidian District Beijing 100084, China
Filing Date：2018-09-29
Issue Date：
Abstract：
The invention provides a circuit system and a control method for directly demodulating a frequency modulated signal based on a phase-locked loop, wherein the system comprises an amplification module for amplifying an input radio frequency signal; a phase discrimination/frequency discrimination module for acquiring a frequency difference and a phase difference between the local oscillator and the amplified radio frequency signal; a band limiting module connected with the phase detection/frequency discrimination module to limit the bandwidth according to the frequency difference and the phase difference and amplify the bandwidth; a controllable gain amplification module that adjusts the amplitude of the output signal of the band limiting module in a controllable manner; and a frequency-controllable frequency synthesizer module which is connected with the controllable gain amplification module and the phase discrimination/frequency discrimination module, and generates corresponding frequency change according to the frequency difference and phase difference signal after gain adjustment, so as to carry out frequency adjustment and tracking. The system has the advantages of simple structure, low power consumption and strong performance, which can also be used for carrier frequency tracking and carrier error cancellation on the basis of demodulation of conventional frequency shift keying.
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