F i g . 6 - 3 6 . T y p i c a l V i d e o F i l t e r i n t e g r a t e d d i s p l a y o f 2 0 0 M H z R F
division signal amplitude on the Type 491. Note the dBm
reading of the Signal Generator attenuator dial, Increase
the variable output attenuation of the Signal Generator
50 dB. Adjust the GAIN control for a 8 division display.
c. Check-Range of GAIN control must equal or exceed
50 dB.
N O T E
If the IF GAIN control does not meet this require-
ment, perform step 36 then recheck.
32. Check INTENSIFIER Control Range
a. Test equipment setup is given in step 29.
b . C h a n g e t h e D I S P E R S I O N s e l e c t o r t o 1 0 0 k H z / d i v .
Uncouple the RESOLUTION control and turn the control fully
clockwise (maximum resolution bandwidth).
c. Set the VERTICAL DISPLAY switch to LOG position than
adjust the GAIN control and the Signal Generator output
for a signal amplitude of approximately 8 divisions.
d. Turn the INTENSIFIER control to the OFF position (fully
C C W
). Set the INTENSIFIER control for a display of nominal
brightness. Set the CONTRAST adjustment to midrange.
e. Turn the INTENSIFIER control fully
C W
. The intensified
portion of the signal should measure between 3.5 and 4.5
major divisions.
Fig. 6-37. Typical display showing incidental frequency modulation,
3 3 .
a.
b.
Check Signal Amplitude at the TO
RECORDER Connector
Equipment setup is given in step 29.
Set the VERTICAL DISPLAY switch to the LIN position,
adjust the Signal Generator output and the Type 491 GAIN
control for a signal amplitude of 6 divisions.
c. Connect a
1×
probe from the test oscilloscope to the
TO RECORDER connector on the back panel. Terminate the
connector into a 600 W Ioad by connecting a 600 W resistor
from the TO RECORDER lack to ground.
d. Check—Signal amplitude should equal or exceed 24
mV
(≥4
mV division of displayed signal amplitude).
34. Check Video Filter Operation
a.
Equipment setup is given in step 33.
b . W i t h t h e D I S P E R S I O N s e l e c t o r a t 1 0 0 k H z / D I V a n d
the TIME/DIV at 5 ms, uncouple the RESOLUTION control
and turn counterclockwise one position from the full clock-
wise position.
c . T u r n t h e V I D E O F I L T E R s w i t c h O N .
d. Check—The display should resemble Fig. 6-36.
e. Decrease the TIME/DIV to .5 s position and check the
display. There should be no appreciable change in the
display, when the FILTER is switched ON or OFF, unless there
is noise in the display. Set the FILTER to the OFF position.
6 - 3 4
Содержание 491
Страница 4: ...i i Fig 1 1 The Type 491 Spectrum Analyzer ...
Страница 24: ...2 16 Fig 2 17 Control set up chart ...
Страница 34: ...Fig 3 1 Function block diagram of the Type 491 3 2 ...
Страница 42: ...Fig 3 10 Block diagram of the video detector and vertical amplifier 3 1 0 ...
Страница 48: ......
Страница 53: ...Fig 4 4 Power Supply Circuit board assembly with wiring color code 4 5 ...
Страница 54: ...Fig 4 5 Horizontal Display circuit board assembly showing color code to pin connectors 4 6 ...
Страница 55: ...Fig 4 6 IF Control board assembly Wiring color code to pin connector 4 7 ...
Страница 64: ...Fig 4 20A Tube subassembly removal procedure 4 16 ...
Страница 65: ...Fig 4 20B Tube subassembly installation procedure 4 17 ...
Страница 68: ...Fig 4 22 Power supply board assembly with component call out 4 2 0 ...
Страница 69: ...Fig 4 23 Vertical Amplifier and Blanking board assembly with component call out 4 21 ...
Страница 70: ...Fig 4 24 IF control board assembly with component call out 4 22 ...
Страница 71: ...Fig 4 24 IF control board assembly with component call out 4 23 ...
Страница 72: ...Fig 4 25 Horizontal display board with component call out 4 24 ...
Страница 73: ...Fig 4 25 Horizontal display board with component call out 4 25 ...
Страница 74: ...Fig 4 26 Phase lock board with component call out 4 26 ...
Страница 88: ......
Страница 90: ...Fig 6 1 Test equipment recommended for calibration of the Type 491 6 2 ...
Страница 91: ...Fig 6 2 Test equipment recommended to measure the dial accuracy receiver sensitivity and response flatness 6 3 ...
Страница 138: ......
Страница 191: ...APPENDIX A BASIC ISSUE ITEMS LIST Basic issue items list will be published at a later date A 1 ...
Страница 192: ......
Страница 195: ...SECTION II B 3 ...
Страница 196: ......
Страница 200: ......
Страница 201: ...SECTION 9 DIAGRAMS MECHANICAL PARTS LIST ILLUSTRATIONS ACCESSORIES ...
Страница 202: ......
Страница 203: ...9 1 ...
Страница 204: ...9 3 ...
Страница 205: ...9 5 ...
Страница 206: ...9 7 ...
Страница 207: ...9 9 ...
Страница 208: ...9 11 ...
Страница 209: ...9 13 ...
Страница 210: ...9 15 ...
Страница 211: ...9 17 ...
Страница 212: ...9 19 ...
Страница 213: ...9 21 ...
Страница 214: ...9 23 ...
Страница 215: ...9 25 ...
Страница 216: ...9 27 ...
Страница 217: ...FIG 1 9 29 ...
Страница 218: ...FIG 2 REAR 9 31 ...
Страница 219: ...9 33 FIG 3 IF CHASSIS PHASE LOCK ASSEMBLIES ...
Страница 220: ...FIG 4 POWER CHASSIS 9 35 ...
Страница 221: ...FIG 5 TIME DIV SWITCH OSCILLATOR ASSEMBLIES 9 37 ...
Страница 222: ...FIG 6 CRT SHIELD ASSEMBLY 9 39 ...
Страница 223: ...FIG 7 CABINET ASSEMBLY HANDLE 9 4 1 ...
Страница 224: ...FIG 8 491 STANDARD ACCESSORIES FIG 8 491 STANDARD ACCESSORIES 9 43 ...
Страница 225: ......
Страница 226: ...PIN 028017 000 ...