A Digital Frequency Synthesizer for Cognitive Radio Spectrum Sensing Applications

This paper presents a wideband digital frequency synthesizer architecture targeted for spectrum sensing applications. The proposed frequency synthesizer architecture is based on digital period synthesis (DPS), which inherently can achieve a wide operational bandwidth, extremely high-frequency resolution, and an instantaneous settling time with low power and area consumption. The performance of DPS and its fundamental limitations are analyzed in this paper. The frequency synthesizer was implemented in a 65-nm CMOS process and it occupies an active area of 0.12 mm 2 . The frequency range of the synthesizer is from 0.1 to 4.267 GHz with a frequency resolution of 0.025-5.38 Hz. In this frequency range, the power consumption is between 3.6-8.4 mW.