RF Receiver Front-End and Frequency Synthesizer Integrated for Intelligent Human-Machine Systems and Wireless Cybernetics

A RF wireless receiver front-end with frequency synthesizer applying in intelligent human-machine systems is presented in this article. The integrated design includes a current-reused LNA, a folded Giber cell mixer, a class-C quadrature voltage-controlled oscillator (QVCO), an IF Gm-C bandpass filter and a frequency synthesizer. A hybrid fractional-N frequency synthesizer with noise filtering technique for wireless cybernetics is proposed. In order to reduce the effects of high order delta-sigma modulator (ΔΣM), and suppress the out-of-band quantization noise, a noise filter is adopted. An integer-N phase-locked loop acts as the noise filter in the feedback path of a fractional-N frequency synthesizer.