Tektronix SC 502, Instruction Manual

Page: 29 / 127

Operating
Inltructlonl-SC 502
5. Adj ust the horizontal Positi o n control to m o v e the
10010
poi nt
of the waveform to the second verti cai l i ne on
the graticule.
6.
Measure the horizontal distance between the 1 00/0
and
90%
pOints.
Be
sure t h e vari able SECONDS/DI V
contrel is i n
the ful ly clockwi se positi on.
7.
M ulti ply the
distance
measured
in
step 6 by t he
setti n g of the SECONDS/DIV switch.
EXAM PLE: Assume that the horizontal di stance
between
the
100/0
and 90%
p o
i
n
t s
is four d
iv i
s i
o n
s
and the
SECONDSIDI V s wi t c h is set to
1
JIS.
Usi ng the period form ul a to fi nd
risetime:
Rise­
time
peri od
horizontal
=
distance X
(divisions)
The
risetime
is 4 JIS .
SECONDSI
DIV
switch
setti ng
Time Difference Measurements
=
(4) ( 1 p&) = 4J1S
The
SC 502 Oscilloscope permits measurement of
time
differen ce between
two
or
more
separate events.
To
measure time difference, use
the
foll owing procedure:
1.
Set
the AC-G ND-DC switches
of both
channels
t
o
either
AC
or DC.
2.
Set
the MODE
switch to either
CHOP
or ALT. I n
general,
Chop
i s
more
suitable for low-frequency si gnals.
More
information
on
determi ning
the mode i s given under
Verti cal D i s pl a y
s
in this secti on.
3. Set t he triggeri
ng
switches
to
tri
gger
the
d
i
s
p la
y
on
channel 1 or channel 2,
whi chever
channel
p
ro v i d e s the
most stable and correct
triggeri ng
for both channels.
4.
Connect the reference signal to the channel l i n p u t
connector and the comparison s i g n a l to the channel
2
i nput connector. The start of the reference Signal shoul d
lead that of the comparison
signal. Use
coaxial cables
or
probes
that have similar time-del ay
characteristi cs
to
c o n
n
e c t the
Signal
to
the input connectors.
5.
If - the signals are o PP o s i
t
e pol arity, take this i nto
account in the final calculation.
2-12
6. Set the channel VOL TS/DIV switches t o produce
about four
divisions of display waveform.
7. Set the triggeri ng control s for a stable display. Set
the SECON DSIDI V switch for a sweep rate whi ch shows
three
or more divisions between the measurement pOi nts,
if possi ble.
8. Adj ust the channel POSI TION control s to bri ng the
measurement points to the center horizontal reference
li ne.
9.
Adj ust the horizontal P O S I TI O N control so the
channel
1
waveform (reference)
crosses
the
center
horizontal l i ne
at
a vertical graticule li ne.
10. Measure the
horizontal distance between the
two
measurement pOints (see Fi g. 2-7).
1 1 . M ulti ply
the
m e a
s
u r e d di stance by
the
s e tti n
g
of
the SECON DS/DIV switch.
�
Iitude
vel
�
Amp
Ie
Ch.nnel 2
1878·3
Rg. 2-7. Me
••
urlng time dlHerenc. between two pUll
EXAM PLE:
Assume that
the SECONDS/DIV
switch is
set to
50
JIS and
the
horizontal
distance between measu re­
ment points is four divisions.
U
si n g the formula:
Time
Delay
=
SECO N D SI
D I V
switch
setting
hori zontal
X di stance
=
(50 JIS) (4) =200
JlS
(di visions)
The time
delay
Is 200 JIS.
@
MAY 1 980