Re: On-topic: HP 1743A portable oscilloscope having unique feature?

Jokken Feldhaar

Hi all,

I don't know if this the exact topic, but a TEK 567 with the 6R1 plugin
and the 3S76 and 3T77 was able to to time interval measurements, even
depending on the amplutude of the trace, not only the sweep position,
and it had picosecond resoluion.

A very versatile plugin, must have been a marvel when it came out in (my
guess) 1961. Awesome, using counters built with discrete transistors and
nixies of course.

Regards, Jochen DH6FAZ

Am 28.06.2017 um 14:54 schrieb @Raymond [TekScopes]:

A few days ago, I acquired two HP 1743A's, both in need of some
repairs. These 'scopes basically are HP 1740A's with a numerical
(B-)delay readout, much like a DM44-equipped 465 or the like at first
After taking care of repairs, I started playing with one of these and
found an interesting and useful consequence of its design that I'm not
aware of in Tek 'scopes from the same or even slightly later period
(1977 - '78), portable or mainframe. Am I mistaken?

These 'scopes allow delta-time measurements using dual markers. They
measure the time between sweep-start and the start of the marker by
counting elapsed time, not by measuring momentary sweep voltage. This
makes the measurement independent of sweep linearity.
The delta-time measurements use highlighting on two independent
alternating B-delayed sweeps.
The most intriguing consequence is the ability to digitally show the
time (3 - 5 digits resolution, floating point format) between e.g.
edges on waveforms without manually moving a cursor; by setting the
"Stop" marker in "triggerable after delay" mode, it follows the Stop
event (within limits) and indicates the time between Start and Stop
marker, even when that time changes. In essence, it's a time interval
counter with 'scope display... Unfortunately, there's only one common
trigger level adjustment for both B-sweeps...

Haven't seen this elsewhere in the period.
Any comments?


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