On 2012-01-08, Chris Albertson <[email protected]> wrote: > On Fri, Jan 6, 2012 at 1:54 PM, E-Mail Sent to this address will be > added to the BlackLists <[email protected]> > wrote: >> On 1/6/2012 12:28 PM, unruh wrote: >>> Eg, your encore pluse is a TTL level pulse (0-3 volt transition) >> >> I thought he indicated he had a Oncore UT+ ? >> >> ?The M12M Oncore specs TTL interface (0 to 3 V) >> ?The UT Plus Oncore TTL specs TTL interface (0 to 5 V) >> ?The GT Plus Oncore specs TTL interface (0 to 5 V) > > I have a UT+ It does 5V logic level pulses but I connect the TTL > level PPS to a MAX232 chip which converts the levels to +/- 8 volts > > I think the problem is my long cable. I'm pushing about 80+ feet of > cat-5 cable. Looks like I will either have to move the equipment or > use RS422 drivers at each end. I'm going to try moving the equipment > to where I can use a quality 4 foot cable.
Make sure you properly terminate the cable with 100 ohms. Otherwise you will get reflections back and forth along the cable, and the cable will slowly fill with charge, broadening the pulse by a huge amount. It may also be that the signal is decreasing due to resistance in the line. > >> > Chris Albertson > Redondo Beach, California _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
