A dual-loop frequency synthesizer with a multi-phase VCO

Abstract

In this paper, a novel dual-loop frequency synthesizer is presented for wireless communications. The synthesizer comprises a dual-loop architecture with a multi-phase Voltage Controlled Oscillator (VCO) in one of the loops. The advantage of this architecture is the improvement of the transient response and channel spacing compared with conventional dual-loop frequency synthesizers. The proposed architecture has been simulated using Verilog-AMS model and implemented on a Xilinx Virtex-5 PFGA board. Simulation results confirm that by using a four phase VCO, transient time of the frequency synthesizers can be reduced by a factor of four with our new dual-loop frequency synthesizer without changing the frequency resolution. Measurement results confirm that the new dual-loop multi-phase frequency synthesizer achieves comparable phase noise but superior frequency resolution compared with the conventional dual-loop frequency synthesizer.

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IET Conference Publications

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