No! John Ferrell W8CCW "All that is necessary for the triumph of evil is for good men to do nothing." -- Edmund Burke http://DixieNC.US ----- Original Message ----- From: "Richard Prosser" To: "Microcontroller discussion list - Public." Sent: Thursday, May 08, 2008 10:13 PM Subject: Re: [PIC]Analog signal conditioning > One of the legs to the pot isn't already connected to the mast or > another cable is it?? > > RP > > 2008/5/9 Jinx : >>> As near as I can tell the noise is only present when the board with >>> the AD is attached >> >> Re-reading earlier posts (so apologies for asking about something >> you'd already mentioned) >> >> "It appears the noise is originating on the board. The AD specs call >> for 1K max input impedance. A unity gain op amp will probably fix >> the problem for my needs" >> >> I'm not aware of an AD conversing creating noise. The impedance >> of your pot is not markedly different from the recommended. Being >> slightly higher you can use a longer sampling time to offset this and >> still get good results >> >> and >> >> "RA3 (AD pin) runs all over the board to the various sockets and >> devices. However, the onboard pot does not exhibit the jitter" >> >> So this perhaps doesn't appear to be a problem with the remote >> pot at all, rather that the signal path from the connector to the AD >> pin is picking up noise. Maybe EMF from a crystal ? >> >> If you substitute the board pot with the remote (or put the board >> pot on long wires) does this make a difference ? How about a >> pot with shortish wires into the connector ? >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist