The modelling and design of a multi-standard frequency synthesis system

The cellular wireless handset has evolved from a device primarily used for voice communications to a ubiquitous device used to deliver information services and multimedia content. Ultimately, the lack of flexibility in the RF section of wireless communications systems limits the ubiquitous nature of these devices. Driven by the desire to both reduce costs and reduce the size of cellular handsets, designers have attempted to integrate an entire functional handset on a single integrated circuit. The drive towards integration has caused many challenges related to the implementation of the frequency synthesizer. This research proposes a frequency synthesizer that leverages Digital Signal Processing to implement a frequency synthesis system for wireless applications. The proposed system would allow multi-standard frequency synthesis to be integrated on a single die with no external components. Circuit simulations are presented that demonstrate the noise performance of a band-switching VCO that maintains both wide tuning range and low VCO gain simultaneously. Behavioral simulations demonstrate the ability of the proposed system to adjust the damping behavior and bandwidth of a phase-locked loop independently, as well as the ability to modify the noise performance of the system as a function system bandwidth.