Tektronix 491, Maintenance Manual

Page: 111 / 226

I N T E N S I T Y
F O C U S a n d A S T I G M A T I S M
I N T E N S I F I E R
SCALE ILLUM
POSITION (Horizontal and
Vertical)
T I M E / D I V
VARIABLE
T R I G G E R
S L O P E
LEVEL
S O U R C E
D I S P E R S I O N R A N G E
D I S P E R S I O N - C O U P L E D
R E S O L U T I O N
I F A T T E N U A T O R d B
IF CENTER FREQ Controls
V I D E O F I L T E R
V E R T I C A L D I S P L A Y
Fig. 6-23. Test equipment setup to adjust IF amplifier and the resolution bandwidth.
Type 491
G A I N
Midrange
Display of nominal
brightness
Adjusted for optimum
display definition.
O F F
As desired
Adjusted for a
horizontally centered
sweep on the graticule
baseline.
2 ms
CAL
+
Triggered sweep
L I N E
k H z / D I V
S e t t h e D I S P E R S I O N t o
50, uncouple the RES-
O L U T I O N c o n t r o l a n d
t u r n f u l l y c l o c k w i s e .
All switches in off position
Midrange (000)
O F F
L I N
P O W E R O N
M I X E R P E A K I N G
SEARCH
F I N E R F C E N T E R F R E Q Centered
PHASE LOCK Controls
INT REF FREQ OFF
Test Oscilloscope
Time/Cm 1 ms
V o l t s / C m
. 0 5
Input Coupling
AC
T r i g g e r L I N E
23. Adjust IF Amplifier Response and
o
Resolution Bandwidth
a. Equipment setup is shown in Fig. 6-23.
N O T E
R e s o l u t i o n b a n d w i d t h s h o u l d b e p r e - a d j u s t e d b e -
f o r e c a l i b r a t i n g t h e k H z / d i v d i s p e r s i o n . R e p e a t
t h i s s t e p a f t e r a d j u s t i n g k H z / d i v d i s p e r s i o n i f
k H z / d i v d i s p e r s i o n e r r o r i s g r e a t e r t h a n 6 % .
b. Apply 200 MHz signal (2nd harmonic of 10 ns) from the
Time-Mork Generator (Type 184) through a 20 dB attenuator
ond proper adapter to the RF INPUT connector.
Two alternate methods of 200 MHz signal application are
as follows:
6-23