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 <[email protected]> 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 <[email protected]> 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 -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
