Vertical Amplifier Plug-I n Units
All 7 A-series plug-in units can be used with the 7844/R7844.
Bandwidth and sensitivity ranges should be taken into con
sideration when selecting amplifier plug-in units.
S I NGLE-TRACE.
Any single-channel amplifier will display
a signal, with the sweep provided by any 7B-series time base
plug-in. This combination leaves 2 unused compartments
available for other special purpose units. Blank p!ug-in
panels are available to cover any unfi l l ed plug-in compart
ments.
DUAL-TRACE.
A dual-channel amplifier in either vertical
compartment can display 2 separate signals with the other
vertical compartment free for other uses.
THREE-TRACE.
A dual-channel amplifier can be used with
any single-channel amplifier to display 3 separate signals. If
2 sweep plug-in units are used in the horizontal compartments
2 signals can be displayed at 1 sweep rate while the other
signal is displayed at the other sweep rate.
FOUR�TRACE.
Two dual-channel amplifiers can display 4
separate signals. I f 1 time�base u n i t is used, all 4 signals will
be displayed at the same sweep rate.
Time-Base Plug-ln Units
The 7844/R7844 is compati ble with time-base units of the
7B70 and 7 B90 series. Sweep rates and triggering ranges
should be taken into consideration when selecting time-base
plug-in units.
To obtain a delayed-sweep display, a delaying time�base
unit must be inserted in the A H O R l Z compartment and a
del ayed time-base u n i t installed in the B H O R ! Z compart
ment. A delayed-sweep display can also be obtained with 1
horizontal plug-in u n i t in either horizontal compartment if
a dual time·base unit is used. This l eaves the other horizon
tal compartment available for other plug-in units as suggested
later in this section.
The 7B50-series time base units are not recommended for
use with this instrument because they require a longer delay
line than is used in the 7844/R7844. ThE)refore, the trigger
ing event may not appear on the display.
@
,,,--,,-,--,,-,,-,-,/",--, '-J-'J',/",
\
CAUTION !
\�_,,/,_.r-._r--_,,/'_�--"
Th e 7853AN Option 1 1 must not b e used in the
7844/R 7844 because the interface connectors
are not totallv compatible.
Operating I nstl'uctions-7844/R7844 Operators
Sampling D isplays
Sampling-system plug-in units for the 7000-series oscillo
scopes provide displays of fast-changing signals that cannot
be examined using any other method. For example, samp
ling systems available for the 7844/R7844 can resolve repe
titive signals having less than 1 0 m i l l ivolts of peak amplitude
and occu ring in less than 1 nanosecond.
The technique used for sampling is very similar in principle
to the use of stroboscopic light to study fast motion. Sam
ples of successive waveforms are taken, ampl ified by a rela
tively low-bandwidth amplifier, and then displayed on the
crt as a replica of the sampled waveforms.
Three sampling systems are available at this time for the
7844: {-1 ) the 7S12, which provides time-domain reflecto�
meter displays or general-purpose measurements, (2) the
7S1 1 17T1 1 system and (3) 7S1 4. a dual-channel vertical
sampling system, including main and delayed sweep func
tions. See the Tektronix catalog to determine the charac�
teristics of the individual units mentioned and of additional
units made available after this manual was written.
SINGLE-TRACE SAMPLING.
A single-trace sampling dis
play requ ires either a dou ble-width 7S1 2 (which includes a
time-base) , or the 7S1 1 sampling unit and the 7T 1 1 sampling
sweep unit. Direct interconnections between the 7 S 1 1 and
the 7Tl 1 require these units to be adjacent, with the 7S1 1
in the R I G HT VERT compartment and the 7 T 1 1 in the A
H O R I Z compartment. If either the 7S1 2 or the 7S14 is
used, it must be located in the 2 middle compartments to
make the proper connections with the 7844/R7844.
DUAL-TRACE SAMPLI NG.
Two 7S1 1 's can be used with
a single sampling-time-base unit for time-related displays of
two signals, Direct interconnections from the L E FT V E RT
7 S 1 1 pass through the R I GHT VERT 7S1 1 to reach the A
H O R I Z time-base unit.
The 7S1 4 is a dual-channel sampling unit with delaying
sweep capabi l ity. It must be used in the 2 center plug-in
compartments.
Dual-trace sampling displays can also be made by a 7 S 1 2 in
the 2 middle compartments and a 7S1 1 in the L E FT VERT
compartment. I n this application the 7S1 2 supplies the
time-base for both traces.
X-Y SAMPLING.
One 7S1 1 inserted in the R I GHT V E RT
compartment and one in the adjacent A H O R I Z compart
ment automatically share a 50 kil ohertz free-r'unning strobe
1-17
