The Design and Application of Programmable Digital RF PLL Oscillators

This paper presents the design of a digital programmable RF PLL local oscillator and its applications in CDMA mobile communication systems based on IS-95.The PLL oscillator is composed of two dual current mode charge pump synthesizer,such as LMX2337/LMX2332A,third order loop filter and VCO.It is employed for the local oscillator of RF mixer and IF modulator/demodulator,as well as the reference clock of baseband module in CDMA mobile system.It has the characteristic of low phase noise ,low power consumption and low operation voltage.Finally,experimental results show that the phase noise of all oscillators is less than -92dBc at 10kHz offset from carrier.