Analysis and realization of wide-band frequency synthesizer in hopping communications
Li Xiao · Application of Electronic Technique · 2009
The paper mainly focuses on designing and implementing the Fractional-N frequency synthesizer with wide-band basing on high order delta-sigma modulator in circuit combined program.The circuit satisfies the requirement of ultra-fine frequency resolution,low phase-noise and fast switching speed performance.The main working frequency range is 1 800 MHz to 1 900 MHz,the aux working frequency range is 600 MHz to 820 MHz.The measured phase noise is lower than 80 dBc/Hz at 10 kHz offset,the spurious is lower than-60dBc,ultra-small step size is 100 Hz or less and switching times is less than 50μs,satisfying the requirement of most wireless communication systems.The new frequency synthesizer exhibits high application potential for low cost relative to high performance.