Operating instructions

When using the single-sweep
mode to photograph
waveforms, the graticule may have to be
photographed
separately in the normal manner to prevent
over
exposing the film . Be sure the
camera system is well
protected against stray light, or operate the
system in a
darkened
room . For repetitive waveforms, press
the
SINGLE SWP
RESET button only once for each
waveform
unless the signal
is completely symmetrical .
Otherwise,
multiple
waveforms may appear on the film . For
random
signals,
the camera shutter can be left
open until the
signal triggers
the unit . Further information
on
photographic
techniques is given in the appropriate
camera instruction
manual .
Single-Sweep Acquisition Using a 7854
Oscilloscope .
"The ACQUIRE-STOP DELAY control and AQS CLOCK
switches
function only with the 71387 installed in the
7854 Oscilloscope B
Horiz compartment . The 7854
requires a sequential
clock signal to acquire a single-
sweep display : this is provided
by the 71387 time-base
unit with the AQS CLOCK/AQR clock switch
in the
INTERNAL
or INI
-
1000 positions or externally through
the EX1 -
CLOCK IN, when in the EXT/AQR position .
Table 1-1 shows the internal
clock frequencies at
different TIME/DIV switch settings,
at X10 MAG settings
and at the INTERNAL and INT
=
1000 settings of the AQS
CLOCK/AQR switches .
The AQS CLOCK/AQR switches
select three clock
operating modes :
2
ms
.5 ms
1 ms
50 pS
__20
NS
10 pS
REVA
MAR 1981
1 .024 kHz
2 .048 kHz
5 .12kHz
_
_
20 .48 kHz
51 .2 kHz
102 .4 kHz
204 .8 kHz
1 .024 MHz
2 .048 MHz
TABLE 1-1
TIME/DIV Setting Relationship
To
7887 Internal Acquire Clock Rep
Rate
1 . INTERNAL----The clock is generated internally,
with the
clock frequency determined by the TIME/DIV and MAG
settings (see Table 1-1) .
The ACQUIRE-STOP DELAY
control varies the allocation
of pretrigger and post-trigger
time
in
the subsequent
stored single-sweep display . The post-trigger
portion is
intensified in the real-time display andthe exact time
is
displayed by CRT readout (see Fig . 1-3) .
Operating
Instructions---7887
NOTE
Occasionally, when using the 7B87l7854, the first
point
of single-shot acquired (A OS)waveform will be
displayed at the end
of the trace (extreme right) and
will appear that the waveform
has made a transition
on the last point . To determine if
the last point is
erroneous, check that the first and last points have
nearly
the same vertical value at any setting of the
71387 ACQUIRE-STOP
DELAY control .
2 . IN1
-
1000----In this AQS CLOCK mode the internal
clock
frequency is divided by 1,000 (see Table 1-1) . The
real-time display is the
same as the internal mode with
the intensified
zone and associated ACQUIRE-STOP
DELAY readout corresponding
to post-trigger time in the
subsequent stored single-sweep display .
X10
-
1000
2 .048 kHz
5 .12 kHz
.
10 .24 _- kHz
20 .48 kHz