John, I don't know if I am going to understand all this. I come from an analog world, a dinosaur, all this timing stuff as much fun as it is, can be awful intimidating.
I am thinking there is a 1 PPS source in the Z3801a but for the moment I have one of these devices http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320751663786 Do you think this will work? Some day when you have some free time, perhaps we could have a phone call or SKYPE if you use that and discuss 1 or 2 of these issues Thank you again Paul A. Cianciolo W1VLF http://www.rescueelectronics.com/ Our business computer network is powered exclusively by solar and wind power. Converting Photons to Electrons for over 20 years -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Miles Sent: Tuesday, August 30, 2011 3:01 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Question for any HP105 owners HP5370 Settings > 1) Under Function > The counter is in the "TI" mode > > 2) Under statistics mode > The counter is in the "Mean" mode > > 3) Under Sample Size > Number "1" is selected > > 4) Under arming > The "+TI" button is selected. > > 5) Under display rate. > Fully clockwise the display nor the GPIB interface will update if > this is in the "hold" position > > 6) Inputs section > All three pots are in the "preset" position. > 10 MHz Z3801A Reference is connected to "Start" DUT is connected to > "Stop > Start Stop inputs are "positive slope" and each is "50 Ohms" > Termination Both input switches are in the "divide by 1 " position. > External BNC has no input. > > External reference drive, in the back = the Z3801A It's probably better not to use one of your test sources as the counter's external reference. That's asking for systematic-bias trouble. The internal 10811 reference is quieter than the rest of the counter for measurements less than ~10 seconds apart, so there is rarely a good reason to use an external reference at all, unless you are looking to measure absolute frequency. > LED displays " 53.20 with the. 20 changing N secs" > Remote led lit > "Talk" in the GPIB area is lit. What limits the rate at which readings are coming out of the counter? You need to either back off the rate control to yield about 10 readings/second or fewer (and let TimeLab measure the interval), or use a 1-pps or 10-pps source on the START or external-trigger jacks. Otherwise I'm surprised the GPIB-Ethernet adapter is keeping up... and at best you are likely to get irregular tau intervals. If/when you go to a pulsed source on the START jack, don't leave the level control in its preset position, or you'll probably get some extra noise near 0V. Use DC triggering and set the level about halfway up the edge (e.g., with 5V pulses in from a CMOS divider, you could set ~2V trigger level in x1 or 0.25V in x2, whichever gives you the lowest residual noise.) -- john, KE5FX _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
