data filter - RF Cafe Forums

RF Cafe Forums closed its virtual doors in late 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2012, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts. Here is the full original RF Cafe Forums on Archive.org

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Rod

Post subject: data filter

Unread postPosted: Mon Mar 28, 2005 3:09 pm

I'm looking for an active filter for my 10kbps TTL data line.

Any ideas what the lowest possible Fc can be for the filter? Any suggestions for MFG's of such filters?

Thank you

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Guest

Post subject: Data Filter

Unread postPosted: Tue Mar 29, 2005 1:47 pm

Hi,

The answer to your question probably comes from several other questions:

1. Why do you want a filter at all?

2. Where is the data going?

3. How much stop-band attenuation do you really need?

4. How much are you willing to pay for the very narrowest possible bandwidth?

The (unattainable!) limit would be 5 kHz. Any reasonably narrow filter will either require a phase equalizer to remove inter-symbol interference, or be many stages of (approximately) linear phase filtering, such as Bessel filters.

Most filters are either custom-made (read $$$) or do-it-yourself with building blocks from an IC company such as Linear Technology (www.linear.com). LTC offers free design software for their chips.

Good Luck!

Posted  11/12/2012