Does the counter have setable input threasholds? Most do. Are they set the the same?
-John ============ > I'm keeping the "newbie question" in the subject for those who wish to > ignore this thread. To those who respond, your contribution to the > diminution of my ignorance is appreciated :-) > > I had borrowed two different 5328A counters. I just compared them, > using the exact same coax, connectors and settings. Both units were > warmed up for over one hour. > > In my previous readings, I was averaging for 1 s and rounding to one > decimal place. The following readings are averaged for 10 s and > rounded to two decimal places. This seemed like a good place to round, > as the readings were stable enough to this point. > > Old 5328A (slide power switch): > + + = 19.43 ns > - - = 19.49 ns > > Newer 5328A (toggle power switch): > + + = 18.92 ns > - - = 19.41 ns > > The A and B inputs on the old unit match much more closely. If I > average the readings of each unit, there is more than 200 ps > difference between the old and new unit. How do I know which one is > correct? > > Joe Gray > W5JG > > On Mon, Apr 4, 2011 at 8:25 PM, Joseph Gray <jg...@zianet.com> wrote: >> Hal, >> >> Here are the results I got using your suggestion. The numbers may be a >> bit different than last night as I'm not sure I'm using the same >> cable. >> >> A+, B+ = 18.9 ns >> A-, B- = 19.4 ns >> >> Obviously there is some difference in delay between the A and B >> channels. Otherwise, the two numbers would have been identical - >> correct? >> >> If I take the average of the two readings, I get 19.05 ns, which is >> more precise than the readings I'm taking. I'm rounding to the nearest >> 0.1 ns on the readings. >> >> A+, B- = 5014.6 ns >> A-, B+ = 5023.5 ns >> >> If I take the average of these two readings and subtract out the 5 us >> for 1/2 period of the 100 KHz square wave, if get 19.15 ns. This >> agrees very closely with the above average. >> >> I haven't looked at the service manual for the 5328A yet, so I don't >> know if I even have the proper equipment to attempt a calibration. In >> the mean time, would you say that taking the average of the first two >> readings is a valid method? >> >> Joe Gray >> W5JG >> >> On Sun, Apr 3, 2011 at 7:18 PM, Hal Murray <hmur...@megapathdsl.net> >> wrote: >>> >>> How about a square wave? Start on one edge, stop on the next cycle. >>> >>> You can play with start on rising edge, stop on falling and the >>> reverse. >>> They should add up to the total. >> > > _______________________________________________ > 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.