Single Chip DWT-IDWT Processor Design with VHDL

Abstract

frames under C.L The applications of Discrete Wavelet Transform necessitate fast computation. Full-custom VLSI devices (ASIC) have been used for fast though expensive implementations of DWT. Field-Programmable Gate Array (FPGA) architectures offer economical but area-constrained implementation of DWT. The present paper proposes an important issues on the design and simulation of ASIC and FPGA architectures for 1-D DWT as well as inverse DWT on a single chip using VHDL simulation tools. The design of the programmable chip that can be used as 1-D DWT or IDWT is introduced based on two quadrature mirror filters (QMF), one used with DWT (decomposition) and other used with IDWT. The design is modular; the chip can easily be worked as DWT or IDWT with ability of selecting one of the four corresponding types of QMF wavelet filters (Daubechies 1, 2, 3 and 4). The first chip is implemented and simulated using FPGA for two word lengths 8-bit and 12-bit respectively. The results show a clock speed of 66.2 MHz for 8-bit, and 55 MHz for 12-bit. While the design of ASIC chip validate a clock speeds 85.5 MHz and 59.2 MHz for 8-bit and 12-bit respectively. Simulation results have established that the higher word length increase accuracy but at the expense of higher designed size and longest combinational logic between two storage elements. This means increasing the length of critical path as result of complexity which decrease the maximum speed clock. Keywords: VHDL, Wavelet, FPGA, Architecture.