2012 Volume 9 Issue 2 Pages 86-91
This paper proposes an architecture-level solution to suppress the phase noise of local oscillators in wireless-transceiver LSIs. Because a phase-looked loop (PLL) supplies only one local oscillator (LO) frequency for multiple channels, large loop bandwidth of the PLL can be used for suppressing the phase noise. Simulation results show that a sixteen-channel grouping can suppress the phase noise more than 24dB in narrow-band wireless systems. Channel selection in receive mode can be ensured by a variable intermediate frequency (IF) complex band-pass filter. Local-leak and image signals in transmit mode can be suppressed by a quadrature up-conversion mixer and radio frequency (RF) band-pass filter with high-IF configuration. A digital-analog converter, analog-digital converter, and digital LSI are in charge of modulation and demodulation of the variable-IF signals.