Hello Mr. farooq kamran,

I did a search on www.google.com for digital filtering with 8051 assembly specified but didn't find anything.

I know digital filtering is all the rage right now but good old analog filtering still has a lot of punch. You might want to check it out.

I did come a lightweight preamplifier
with the following features. It has a schematic, printed circuit board foil pattern and is well documented. It has the following features.

1. Low cost (less than $50).
2. Gain 100-1000,
3. a.c. coupled.
4. Noise comparable to commercial units
5. Very good Common-mode rejection.
6. Good perform for 60 Hz noise in environments.
7. 5 kHz lowpass filter.

The web address is http://www.nbb.cornell.edu/neurobio/...TS/PREAMP/


Good luck,

Charles Bannister