Tektronix 323, Instruction Manual

Page: 22 / 170

Operating Instructions— Type 323
the increase in gain when the X 1 0 VERT GAIN control
is out. Return the X 1 0 VERT GAIN control to its in posi­
tion.
8. Set the VOLTS/DIV switch to .02. Observe that the
5 DIV CAL square wave is replaced by a horizontal trace
which appears approximately 2'/2 divisions below graticule
center. Reset the trace to graticule center. This will be used
as the DC reference position. (The DC reference position
can be arbitrarily established anywhere on the CRT by
adjusting the vertical POSITION control while the probe
tip is grounded or the INPUT switch is at GND position.)
9. At the side panel, connect the Type P6049 probe cable
to the VERT INPUT connector. Connect the probe tip to the
0.5 V square-wave signal at the CAL OUT jack.
10. Switch the INPUT control to DC. Observe that a
square wave 2’/ 2 divisions in amplitude appears on the
CRT. The instantaneous voltage at the top and bottom of
the square wave can be measured as follows:
Determine the number of divisions of separation between
the previously established DC reference and the top of the
square wave. Multiply by the value of the VOLTS/DIV knob
setting and the probe attenuation factor. The position of the
top of the trace is above the DC reference indicating a posi­
tive voltage. The bottom of the trace appears at the DC
reference point. The trace is operating between 0 and
+0.5 V DC. See Fig. 2-5(A) and (B).
11. Switch the INPUT control to AC. Note that removal
of the DC component causes the trace to shift downward,
centering around the previously established trace DC ref­
erence position. See Fig. 2-5(C).
12. Compute the signal amplitude. .02 VOLTS/DIV deflec­
tion factor multiplied by the 10X probe attenuation fac­
tor and by the 2'/2 divisions of deflection equals 0.5 V sig­
nal amplitude. Note that this equals the difference between
the waveform's DC voltage limits found during DC measure­
ment in step 10, although the waveform's DC operating level
does not appear.
13. Set the VOLTS/DIV control to 0.1. Note that the dis­
play amplitude reduces to '/2 division. Again calculate the
input signal amplitude (0.5 V).
14. Pull the X 10 VERT GAIN control out. Note that the
display amplitude increases to 5 divisions. Compute the
display amplitude by using the following procedure:
Divide the VOLTS/DIV setting by 10 to determine the
vertical deflection factor with the X 10 VERT GAIN out.
Multiply this deflection factor by the number of divisions
of deflection and the 10X probe factor to determine the
input signal amplitude (0.5 V).
(The 10X probe attenuation is effectively compensated for
by the X 1 0 Vert Gain switch; under this condition, the
vertical deflection factor reads directly from the VOLTS/
DIV control setting—5 div X .1 V/DIV — 0.5 V signal input.)
Operating the Horizontal Controls
15. Calculate the square wave period time. Multiply the
number of divisions per one cycle of square wave by the
1
' .: t
,\V.
&
•;V-
•‘y •
V > \.
t t i i
V
y r r
I I I ! jr iV i it.l.f I M I
m i
. > *
t m
M .
l i l t l i l t
■ I':-.-
.
*. v.
■
V* V ,
• •-v
,v; •
V.
kVM -'-A-*’. \ '
S—
- •
(A ) DC reference po sitio n set a t g raticule vertical center.
P + 0 . 5 V
- . 0 V
.
•i
I
i
i
i
s i
M
:■
i s g
SI ' • *
_ _
/.‘ v \ i f
u
: \
■
j * * #
.
: 8 i
! S f
iPHKt
L\>V,
L V .+ -
* 14 1
______
'•V •
i i i ■
1 1
______
TTT •
g - j
*■ • f ,
a ®
.—
v k ’ •]
R
_ _
i'.V .; ....
;
;•
•
.
. ,\V
•'-V* ■]
J B B C n S M U lllL IM IU II.U I r . 'J , ; ----■..* * !. " ■ '1 .1 T..
(B) 0 .5 V square wave signal DC-coupled in to vertical cir­
cuit. DC o p eratin g level and signa l am plitude can be
determ ined. D eflection Factor .2 VOLTS/DIV.
He- >r *'- J - -
)
1
I
:
•<
1
L
• 'v . .
M
i u i ' f
’ T
0 .5 V
w m
> £ /
4
—
•
m i
till
H U m i i l l . IH 1
V
r?1 ’ ■ ■
1 • ~
T r i r
r-.-'v
t
TTT
'
.
/,
y.
'
>
“■T-‘ ■ »
(C) Same signa l, A C -coupled into vertical circuit. Note th a t
signal DC o p e ra tin g level cannot be determ ined.
Fig. 2 -5 . DC versus AC in p u t coupling.
TIME/DIV setting. Reset the vertical POSITION knob as
necessary for convenient measurement. (Approximately 1.3
ms per cycle.) See Fig. 2-6.
16. Calculate the square-wave frequency by determining
the reciprocal of the period time. (Approximately 750 Hz).
17. Switch the TIME/DIV control to 2 ms. Observe that
approxiamtely 1'/2 square waves per division are now be­
ing displayed. Calculate period time (approximately 1.3 ms)
and frequency (approximately 750 Hz).
18. Pull the X 10 HORIZ MAG out. Observe that about
1 square wave per seven divisions is now being displayed.
Calculate the period time and frequency. (It is still approxi­
mately 1.3 ms and 750 Hz respectively.)
2-10