2001 Volume 22 Issue 6 Pages 407-414
In this paper, we present a VLSI implementation method on a dynamic range controller, audio level compressor, which is used to make sound effects as an important functional part in a digital audio system on a chip. To implement the gain calculation in a digital dynamic range controller, a power calculation with fractional numbers is required and it is difficult to be performed directly in a digital audio system. We introduce a polynomial expression to approximate the power operation, then the gain calculation is easily performed with a number of additions, multiplications and a division. Based on the gain calculation method of the gain, an efficient VLSI architecture with some arithmetic circuits is proposed. We designed the circuit of a 16-bit audio level compressor by using a hardware description language, VHDL. As a result of the compact circuit design, the 16-bit compressor has only 5,688 gates by 1 μm CMOS gate array technology. The design and simulation results show that the presented audio level compressor has high performance and can be integrated into an audio system on a chip for practical use.
