Design and FPGA Implementation of CORDIC-based 8-point 1D DCT Processor

Abstract

CORDIC or CO-ordinate Rotation DIgital Computer is a fast, simple, efficient and powerful algorithm used for diverse Digital Signal Processing applications. Primarily developed for real-time airborne computations, it uses a unique computing technique which is especially suitable for solving the trigonometric relationships involved in plane co-ordinate rotation and conversion from rectangular to polar form. It comprises a special serial arithmetic unit having three shift registers, three adders/subtractors, Look-Up table and special interconnections. Using a prescribed sequence of conditional additions or subtractions the CORDIC arithmetic unit can be controlled to solve either of the following equations:
Y’=K (Ycos λ+ Xsin λ)
X’=K (Xcos λ - Ysin λ); where K is a constant
In this project:
• A CORDIC-based processor for sine/cosine calculation was designed using VHDL programming in Xilinx ISE 10.1. The CORDIC module was tested for its functionality and correctness by test-bench analysis. Subsequently, FPGA implementation of the CORDIC core followed by ChipScopePro analysis of the output logic waveforms was performed.
• Using this CORDIC core a DCT processor was designed to calculate the 8-point 1D DCT. The functionality and operational correctness of this processor was tested, first on the test-bench and then via ChipScopePro analysis, post FPGA implementation.
The output obtained in both the cases was compared with the actual values to test for consistency and the percentage of accuracy was established. Power consumption and FPGA resource utilization were observed. The results obtained were discussed.