Thanks for the tips John. Do you use the 50 ohm or 1M ohm settings with the TADD-2?
Dave On Sun, Feb 28, 2010 at 7:42 PM, John Miles <jmi...@pop.net> wrote: > What threshold are you using? If you leave it set to preset/0 volts, you > may find that crosstalk between outputs on the TADD-2 cause false > triggering. I usually use the divide-by-10 setting with the threshold set > to about 0.25V. > > It also helps to remove the jumpers from any outputs on the TADD-2 you > aren't using. > > -- john, KE5FX > > > -----Original Message----- > > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on > > Behalf Of Dave hartzell > > Sent: Sunday, February 28, 2010 7:28 PM > > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Achieving maximum performance when driving > > 5370A/Binputs > > > > > > Today I have been trying to drive a 5370B directly from a TADD-2, with > > little luck (other HP freq counters seem to work OK). I was about to > ask > > about it on this list, but noticed this thread. > > > > I guess this could explain why I am getting erroneous, random readings? > > > > Dave > > > > > > > > On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths > > <bruce.griffi...@xtra.co.nz > > > wrote: > > > > > The attached excerpts from the 5370A and 5370B manuals indicate that > for > > > best performance, that the common practice of driving the > > 5370A/B 1x inputs > > > directly from a 5V CMOS logic signal is a bad idea. > > > > > > For the 5370A attenuating the 5V CMOS signal to a 1V swing with the > > > threshold set to 0.5V is close to optimum. > > > An input signal with limits of 0V and +1.4V with a trigger threshold of > > > 0.7V is the maximum usable (for high performance). > > > An input signal with limits of 0V and +0.3V with a trigger threshold of > > > 0.15V is the minimum usable (for high performance). > > > > > > For the 5370A attenuating the 5V CMOS signal to a 2V swing with the > > > threshold set to 1V is close to optimum. > > > An input signal with limits of 0V and +3.5V with a trigger threshold of > > > 0.7V is the maximum usable (for high performance). > > > An input signal with limits of 0V and +0.3V with a trigger threshold of > > > 0.15V is the minimum usable (for high performance). > > > > > > Bruce > > > > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.