Tektronix 7B10 Instruction Manual page 22

Operating
Instructions
-
7B10
RISE
TIME
n
I
-
1
•
J
:
/
1
1
1
MM
l(
7
I
1
V
/
1
1
i._
(
1
,
MEA
SURE HORI
A TO
ZON1
B
(101
AL
D
i
TO
ISTAI
50%)
MCE
F
ROM
FALL TIME
1
;
n
'V
:
u
>
1
:
1
1
1
1
4-
r
MM
k
1
;
\ J
1
MEA
SURE
HOR
V
TO
E
ZON'
(90%
FAL
TO
1
IISTA
0%)
NCE
ROM
c
1985
1 1
A
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
= (divis ions) x setting
Magnification
Substituting values:
2.5 X
0.1
jUs
Rise
Time
=
= 0.25 microsecond
PULSE
WIDTH
MEASUREMENTS
Perform the following procedure
to
measure
the pulse
width
of a
displayed
waveform
1.
Install
the
time-base
unit
m
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.)
PULSE WKDTH
Fig.
2-7.
Measuring
the pulse
width
of a displayed waveform.
2-10