Glenn, You can drive the LED from the DCD line, but along with a series resistor you need to be sure to include an extra steering diode in series with the LED. LED's have absolutely no sense of humor about being reverse biased above a volt or two. This might also affect your 1PPS pulse accuracy. If you do it this way use a high efficiency LED and draw as little current through the LED as necessary.
Randy ________________________________________________________________________ ______________________________________ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glenn Sent: Thursday, May 04, 2006 12:35 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Oncore 1pps driver & LED Could I just drive the LED off the DCD line? thanks, glenn Randy Warner wrote: >Glenn, > >You "should" be alright. You're driving a lot of CAT5, but since the >data is only at 9600 baud you should be OK. The 1PPS on the DCD line >will be fine too. To blink an LED you just need to buffer the 1PPS >signal coming out of the UT+ as it does not have enough drive capacity. >Just about anything will work: IC buffer or inverter (I use standard >74LVC04's in my designs) or just a simple xstr inverter or emitter >follower. > >Randy > > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts