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Poul-Henning Kamp
phk at phk.freebsd.dk
Wed Aug 23 18:44:00 EDT 2006
I've been playing with my HP5370B and HP J06-59992A tonight ;-)
I am surprised by how consistent the calibration results
are.
When using 10K sample averages, 10MHz/1.5Vpp square from a HP33120A
they vary only a few picoseconds:
TI++ TI-- TI+- TI-+ TI++-- TI+-+-
-----------------------------------------------------
281.150 215.050 206.850 292.200 0.000 -2.175
280.750 215.350 207.050 288.550 0.000 0.100
281.800 215.950 207.650 288.750 -0.225 0.100
281.900 216.000 208.300 293.100 -0.150 -2.300
1MHz/1.5vpp square, also from HP33120A:
TI++ TI-- TI+- TI-+ TI++-- TI+-+-
-----------------------------------------------------
107.300 30.000 2.200 139.800 0.250 2.600
107.000 30.750 3.000 140.850 0.075 1.275
106.650 30.050 2.600 139.600 0.300 2.100
106.850 30.800 2.650 141.600 0.325 2.075
10MHz via TADD-1 from PRS10:
TI++ TI-- TI+- TI-+ TI++-- TI+-+-
-----------------------------------------------------
275.450 183.900 177.700 278.700 0.825 0.500
277.100 182.500 178.050 282.800 0.800 -2.275
276.150 182.250 178.250 285.700 0.650 -2.425
278.400 180.350 179.000 281.300 1.175 0.400
The interesting thing is that it is also possible to compare coax
cables to each other using this method: not measuring the absolute
propagation delay of course, only the relative propagation delay
between two cables...
But still... light takes 3ps to travel a millimeter...
Enjoy!
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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