Voltage divider (1k:50R) takes a 5 volt signal down to the 250mv the input is expecting. Add a few hundred pf cap across the input to remove the HF noise components. R Gus S Calabrese wrote: > I have a handheld frequency counter that measures from DC to 2 GHz. > It has a BNC connector and 50 ohms input impedance. > ( Battery operated ) > It does okay measuring transmitter frequencies with a stub antenna. > I tried to measure a TTL level signal at that is around 500KHz. > The readout bounced around and was clearly reading RFI from the board. > What kind of probe can I put on this puppy to read TTL signals and > ignore > RFI ? > Regards > > Gus S Calabrese > Denver, CO > 720 222 1309 303 908 7716 cell > I allow everything with "spamcode2006" in the subject or text to > pass my spam filters > > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist