Subject: Re: Thunderbolt at NTP ref clock. From: DaveB <[email protected]>
In article <[email protected] stop.com.au>, [email protected] says... > > Sorry typo - 74AC121 should say 74AC123 > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Mark C. Stephens > Sent: Friday, 2 August 2013 11:01 AM > To: DaveB; [email protected] > Subject: Re: Thunderbolt at NTP ref clock. > > You can control the thunderbolt PPS width with Lady Heather software: > http://www.ke5fx.com/heather/readme.htm > > Or build the TAPR fat PPS Pulse stretcher section on breadboard, not so > complicated, just use the 1/2 of 74HC121 and a 74AC04 (or MAX232) to drive > the serial port (or LPT port - less jitter) make sure any unused inputs are > on the other 1/2 are tied to ground or pulled up to VCC. > The circuit for the 74AC04 can be lifted from the output section of the TAPR > PPS distribution amp (TADD-3). > Or, you can use Just use the FATPPS circuit in its entirety - I built 3-in-1 > custom PPS stretchers on one breadboard and it took me 1-2 hours. > > Please drop me an email if you need me to express this in a circuit. > > > --marki No Worries. I'm an long time hardware fiddler too, so monostables (IC and descrete) are understood by me. (As well as multi kW broadband RF amps and transmission lines.) Thanks anyway. LH can indeed control the PPS signal, but only turn it on or off, or change it's polarity, & position (delay) wrt selected reference time (cable delay and all that.) The default is 0 to +5V, the "other" polarity, is 0 to -5V. I checked with my trusty Tek 465 (and through term!) No ability to adjust the pulse width/duration, so a stretcher will be built. Cheers. DaveB. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
