This is a read-only archive of an earlier blog posting. Reasons for the change are at

The permanent version of this post - with comments (if any) - is at

Desampling using a Cascaded Integrator Comb filter

Been working with a BeagleBoard for the last few months. Can't say much about the project but the Beagle is a nice ARM Linux platform. Finishing up, so now I have more time to update the MHZ100Q sourceforge project page.
I've now added a page describing the ideas behind the Cascaded Integrator-Comb (CIC) filter, and why it makes such a nice desampling filter for a high-rate data acquisition system. Input is 100MHz at 8 bits, and the output is any integer submultiple down to about 1kHz. The hardware resources in the FPGA are low: a set of 64-bit adders and registers, along with a reasonable amount of control logic.
The first version of the page is general description and overview. I plan to put more details of the math behind the CIC. In researching math and html, I found asciimathml.js . It's an open source JavaScript package that lets one embed equations into a webpage's text using simple LaTeX-like strings. I've used it internally and it's really nice to use. Should be live on the mhz100q page in the near future.

Comments on

To make or view comments, see the original post at