What I mean, and I haven't yet given this much thought, of using the two channels differentially in order to create a data set that would represent what's happening on one input signal. What's important about this is that nearly everyone has a PC with that audio-frequency input and the capability of processing two concurrently sampled data sets.

The key, of course, is to make something simple and inexpensive enough that the typical hobbyist who doesn't have budget for a reasonable instrument could use it in combination with his PC to observe/examine low-frequency events he otherwise couldn't. I suppose this could serve a wide range of low-frequency requirements, though synchronizing it with other events might be a mite tricky. Even triggering would be a bit of an effort, though software is quite capable of looking for levels once the AC-coupling matter is handled.

Suggestions?

RE