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amount of time between start of the A Sweep and start of
the B Sweep) is accomplished with
the
B DELAY TIME PO-
SITION control. With either ALT or B HORIZONTAL
MODE
selected and B TRIGGER LEVEL
control
set fully clockwise
(BRUNS AFTER
DLY),
the B DELAY
TIME POSITION
con-
trol provides continuously variable positioning of the start
of
the B
Sweep.
The range of this control is sufficient to place
the B Sweep interval at most any location within the A
Sweep interval. When ALT HORIZONTAL
MODE
is se-
lected, the B
SEC/DIV
switch setting
determines
the
B
Sweep speed and concurrently sets the length of the
inten-
sified zone on the A
trace.
Using delayed-sweep magnification may produce a dis-
play with some slight horizontal movement (pulse jitter).
Pulse jitter includes
not
only the inherent uncertainty of
trig-
gering the delayed sweep at exactly the same
trigger
point
each
time,
but also jitter
that
may be present in the input
signal. If pulse
jitter needs
to be measured, use the "Pulse
Jitter Time
Measurement·
procedure which follows
the
dis-
cussion of "Magnified Sweep Runs After
Delay."
Magnified Sweep
Runs
After
Delay
The following procedure explains
how
to operate
the
B
Sweep in a nontriggered mode and
to
determine
the result-
ing apparent magnification factor.
1.
Preset
instrument controls and obtain a baseline
trace.
2. Apply the signal to either vertical channel input con-
nector
and set
the
VERTICAL
MODE
switch to display
the
channel
used.
3. Set the appropriate
VOLTS/DIV
switch to produce a
display of approximately
2-
or 3-divisions
in
amplitude and
center the display.
4. Set the
A SEC/DIV
switch
to
a sweep speed
which
displays
at
least one complete
waveform
cycle.
5. Select
ALT
HORIZONTAL
MODE. Adjust
both
the
appropriate channel
POSITION
control and
the
A/B SWP
SEP control to display the A
trace
above the B trace.
6.
Adjust
the B DELAY TIME POSITION
control
to
posi-
tion the start of
the
intensified zone to
the
portion of the
display to be
magnified
(see Figure
4-10).
Operating
Procedures-2215A
Operators
0 ••••
10
9
INTENSIFI
ED
ZONE
TO BE MAGN
IFIED
""
...
....
...
(A)
A INTENSIFIED
DISPLAY
V
0
....
....
.
...
....
0
(B)
B
DELAYED
D
ISPLAY
.
.
..
..
..
.
...
.... ....
Figure 4•10. Delayed-sweep
magnification.
....
....
C4207·
21
7. Set the B SEC/DIV switch to a setting which intensi-
fies the
full
portion of the
A trace
to be
magnified.
The inten-
sified
zone
will be
displayed
as the B trace
(see Figure
4-10).
The B
HORIZONTAL MODE may
also be used
to
magnify
the intensified portion of
the A
Sweep.
8.
The
apparent sweep magnification can
be
calculated
from the following formula:
Apparent
Delayed Sweep
Magnification
A SEC/DIV
switch setting
B
SEC/
D IV
switch
setting
EXAMPLE: Determine the
apparent magnification of a
display with
an
A
SEC/DIV switch setting of
0.1
ms
per
division
and a
B
SEC/
DIV switch setting of
1
µs
per
division.
Substituting the given values:
Apparent
=
1 x
10
4
=
102
=
100
Magnification
1
x
1
0 -6
4-9
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