10-05-2013, 12:16 PM
FPGA Based Design of Digital Wave Generator Using CORDIC Algorithm
FPGA Based Design.pdf (Size: 829.73 KB / Downloads: 69)
Abstract
In this paper an efficient approach is presented to
design and implement a high speed and area
efficient Digital Sine and Cosine Wave
Generator for wireless applications like SDR and
GSM. The implementation is based on
Coordinate Rotation Digital Computer
(CORDIC) algorithm which uses shifts,
additions and a very small lookup table (LUT). It
is an efficient method used to compute
trigonometric functions, multiplications,
divisions, data type conversions and hyperbolic
functions in a simple and elegant way. The
proposed design is synthesized with ISE 10.1i
software, simulated with Modelsim 6.3XE
simulator and implemented on Spartan-3 FPGA
target device using Chipscope 10.1. Results
show enhanced performance using proposed
CORDIC algorithm in terms of speed, area and
power utilization.
Introduction
Digital signal processing (DSP) algorithms
exhibit an increasing need for the efficient
implementation of complex arithmetic
operations. The computation of trigonometric
functions, coordinate transformations or
rotations of complex valued phasors is almost
naturally involved with modern DSP algorithms.
Popular application examples are algorithms
used in digital communication technology and in
adaptive signal processing. While in digital
communications, the straightforward evaluation
of the cited functions is important, numerous
matrix based adaptive signal processing
algorithms require the solution of systems of
linear equations, QR factorization or the
computation of eigen values, eigenvectors or
singular values.
Circuit Description
Figure2 shows the CORDIC pipelined
architecture for one iteration. All internal
variables are represented by a fixed number of
digits, including the pre calculated angle αm,i
which is taken from a register. Due to the limited
word length some rounding or truncation
following the shifts 2sm,i is necessary [3]. The
adders/subtractors are steered with -mμi, μi and -
μi, respectively.
Conclusion
In this paper, a pipelined CORDIC algorithm
based design of digital sine and cosine wave
generator for modulation and demodulation in
wireless communication is presented. As
compared to other techniques, CORDIC
algorithm based designs show better results in
terms of speed and area utilization when applied
to wireless applications like SDR and GSM. The
proposed design operates at a maximum
frequency of 161.65 MHz along with efficient
power and area utilization to provide cost
effective solution for wireless applications.