Design an all digital PLL with ripple reduction technique

Abstract

The article describes about the design and implementation of advance version of Phase Lock Loop (PLL) is All Digital PLL. Research work is on ADPLL where parameter ripple is reduced by applying the technique of ripple reduction technique. Ripple reduction technique reduces the use of Kth counter, Kth counter comes under consideration when enable is ON. Phase locked loops are most widely used in communication system. Most of the PLL’s that are used currently are hybrid type PLL’s where all the blocks are assumed to be digital. The circuit design of ADPLL consists of Digital Controlled Oscillator (DCO), loop filter and Phase Frequency detector (PFD). Here phase detector used is Ex-or gate, for loop filter, Kth counter is used and Increment/Decrement circuit is used as DCO. Divide-by-N counter is used for feedback system. The output of the DCO is going in the PFD through the feedback network. Xilinx Vivado suit 2018.2 tools is used for simulating Verilog code. Board chosen in vivado is zed board Zynq. First, with the help of circuit diagram of ADPLL Verilog code is being written on project window. After compilation of code it is simulated with the help of test bench. After that it is going to be implemented and verified with the board zedboard. Number of LUTs used are 32 and Flip Flops used are 35. This paper presents an all digital approach for the design, simulation, synthesis and implementation of FPGA based ADPLL centered at 195.31 KHz using Verilog HDL code. The proposed design methodology resulted in reduction of ripple, power dissipation, junction temperature of board. Proposed research work further can be used in communication for frequency synthesizer. Any system whether it is from communication or digital etc ADPLL is common to use for ripple reduction at its output. So ADPLL is basic building block in any type of communication system.