Chapter 8 Multirate Techniques and CIC Filters
Note: This chapter is an enhanced reprint of the article “The darker side: Multirate techniques and CIC filters,” Circuit Cellar, no. 231, October 2009.
In Chapter 7, I talked about finite impulse response (FIR) filters. In a nutshell, FIR filters allow a digital filter to be implemented with virtually any response curve in a DSP, FPGA, or even a microcontroller, but at the expense of a quite significant number of arithmetic operations. For example, to implement a 32-tap FIR filter, you need to perform 32 multiplications and 31 additions per sample, which translates into a lot of MIPS if your application requires a high sampling rate.
In Chapter 7, I talked about finite impulse response (FIR) filters. ...