Tektronix SC 502, Instruction Manual

Page: 28 / 127

1
1
Horluntal
....
1
dillan,e
l
1000·20
Fig. 2-5. M
••
lurlng time
duretlon (period) between poIntl
on •
w ••
efonn.
POSITI ON
control to center
the
ti me-measurement
poi nts
within the
center
eight
di visions of the graticule.
4.
M
easu
r
e
the
horizontal distance between
t
h
e
ti me
meas u rement poi nts. Be sure the vari able SECO N D S/DIV
control is f
ul
l y
clockwise.
5. Multi ply the distance
measured in
step 4
by the
setting
of the SECONDS/DI V switch.
EXAM PLE: Assume
that the
horizontal
distance
between
the time-measurement
poi
nts is five divisions
and
the
SECONDS/OIV switch
is set to .1
ms. Usi ng
the
form ul a :
Period
=
horizontal
distance X
(divisions)
SECONDSI
DIV
switch
setting
=
(S) (0. 1 ms)
=
The
period
is 0.5
ms.
Determi ning Frequency
O.S ms
The
time
measurement
technique can also be used
to
determine the
frequency
of
a
signal. The frequency
of
a
periodically
recurrent
signal
is the
reci procal o
f
the
time
d
u r
a
t
ion (period) of
one cycle.
Use
the followi ng
procedure :
1 .
Measure
the
period
of one cycle of the
waveform
as
described
in the
previous
appl ication.
@ MAY
1 980
Operating Inllructlonl-SC
502
2. Take
the
reciprocal
of the period
to determine
the
frequency.
EXAM PLE: The frequency
of
the
signal shown
in
Fi g.
2-5,
whi ch has a period of 0.5
ms
i s:
Frequency :;
1
period
Alsetlme Measurement
1
O.S ms
= 2 kHz
Risetime measurements
em ploy basical ly
the same
techniques
as
the
time-period measurements,
The mai n
difference is
the
poi nts
between which
the
measurement
is
made.
The followi ng procedure gives the basic method of
measuri n9
risetime between the 1 0%
and 90%
poi
nts of the
waveform.
1 . Connect the
signal
to
the
i nput
con nector.
2. Set the
desi red
channel VOL TS/DI V
switch and
variable VOL
TS/DI V control to
produce
a
display
exactly
five divi si o ns I n amplitude.
3.
Center
the
display
about the
center horizontal
graticule line with the channel Positi on control.
4.
Set
the time-base
tri ggeri ng
controls to
obtai n a
stable
display.
Set the
SECONOS/DIV switch
to
t he
fastest
sweep r a
te that
wi ll
di splay
less
than
e i
g
ht
divisions
between the 10%
and 90%
poi nts on the
waveform ( see Fig.
2-6).
100%
.... _-
.... ......
90%
point
0%
... . .. .
'::t
. . . . .... .... . . . .. . . . . .. . . . . . . ...
, u'- i
J..
Ho,izonhll '"
, distance
I
Fig. 2-8. Me
••
urlng
rI
..
tlme.
1878·37
2-1 1