Design and implementation of digital RF transmitter for bluetooth applications

A novel fully digital architecture for a multi gigahertz RF transmitter that meets blue tooth specifications is presented in this paper. The transmitter architecture uses All Digital Phase-locked loop. (ADPLL) in contrast to charge-pump PLLs used in analog transmitters. The ADPLL has several advantages when compared to traditional Charge-pump PLLs. The conventional RF frequency synthesizer architecture, based on the voltage-controlled oscillator and the phase /frequency detector and charge-pump combination, has been replaced with a digitally controlled oscillator (DCO) and a time-to-digital converter, respectively. All digital blocks are synthesized using VHDL code. The RF transmitter so created can be used for any short-range wireless applications and it can also be integrated with DSP systems as a System-on-chip (SoC).