Improve group delay response in the anti-aliasing filter:  05/01/98 Electronic Design - Ideas for Design / (added 01/05)  You can dramatically improve the group delay performance of a video digitizer by using the antialiasing filter shown (Fig. 1) instead of a Butterworth anti-aliasing filter. Anti-aliasing filters are necessary. . .

L-C Transformer Cuts Cost And Size, Adds Low-Pass Filtering:  07/21/03 Electronic Design - Design Briefs / (Circuit added 9/04)  L-C equivalents of microwave quarter-wave transformers provide cost savings, miniaturization, and supplementary low-pass filtering. Typically, these transformers have been synthesized directly with published design tables.1, 2 But the. . .

Variable Low Pass Filter:  Unpublished 1995 - A second order variable bandwidth low pass filter is formed using one IC and some passive components. This low cost circuit is good out to 2.5MHz. (Circuit added 9/04)