Pulse Width Measurements - Tektronix 7B10 Instruction Manual

Operating Instructions—
7B10
Operators
IOC
9C
K
RISE TIME
s
:
A
1
i
1
1
1
1
1
y
^
;
1
1
1
;
1
—
IOC
9(
K
(
1
1
MEASURE
1
HORI
A TO
ZON1
B
(101
rAL
D
i
TO
ISTAI
30%)
MCE
F
ROM
FALL TIME
:
:
]S
1
V
1
1
1
1 1 1
1
'
"
i
1
1
1
1
1
;\
1
:
>1.
—
:
_
1
po'
MEA
SURE
/
HOR
\
TO
E
IZON
(90°/
FAL
C
TO
1
<
—
O
NCE
=
ROM
C
1985-1 1A
PULSE
WIDTH MEASUREMENTS
Perform
the following
procedure
to
measure
the pulse
width
of a displayed
waveform:
1.
Install
the time-base
unit in a
mainframe
horizontal
compartment
(either
A
or
B
horizontal
in a four-
compartment
mainframe).
2.
Connect
the
signal to be
measured
to
the
vertical unit
input.
3.
Set the mainframe
horizontal-
and
vertical-mode
switches
to
display the time base and
vertical
unit.
(Check
that
the time base
VARIABLE
(CAL
IN) control
is
pushed
in
and
the
HOLD
OFF
control
is
in
the
MIN
position.)
4.
Set the
TRIGGERING
switches and LEVEL
control
for
a
stable display (see General Operating
information
for
selecting proper
triggering).
5.
Set the
vertical
deflection factor and
position control
for
about
a 5-division
pulse
vertically
centered on
the
graticule.
6.
Set the
TIME/DIV
switch and POSITION
control
for
1
complete
pulse displayed within the center 8
graticule
divisions as
shown
in
Figure 2-7.
7.
Measure
the
horizontal distance
in
divisions
between
the
50%
amplitude
points
of
the displayed pulse
(see
Fig.
2-7.).
8.
Multiply the horizontal distance
measured
in
step
7
by
the
TIME/DIV
switch
setting. (Divide the
answer
by
10
if
sweep
magnification
is
used.)
Fig.
2-6. Measuring
the
rise
time and
fall
time
of a displayed
waveform.
Example:
Assume
that
the
horizontal distance between
the
50%
amplitude
points
is
3
divisions,
and
the
TIME/DIV
switch
setting
is
.1 fjs
(see
Fig. 2-6).
Using the
formula:
Horizontal distance
TIME/DIV
Rise
Time
=
(divisions) x
setting
Magnification
Substituting values:
_
2.5 X
0.1
/is
Rise
Time
=
^
= 0.25 microsecond
PULSE WIDTH
Fig.
2-7. Measuring
the pulse width
of
a
displayed
waveform.