ELECTRICAL CHARACTERISTICS
(cont)
Characteristic
Performance Requirement
S u p p l e m e n t a l I n f o r m a t i o n
Dispersion
M H z / D I V R A N G E
Range
.2 MHz/Div to 10 MHz/Div
In a 1-2-5 seauence
Accuracy
See Table 1-2
Linearity
±3% (over an 8 division display)
k H z / D I V R A N G E
Range
1 kHz/Div to 500 kHz/Div in a 1-2-5 se-
quence and zero dispersion.
Accuracy
±3% of each setting
Over the ±2.5 MHz range of the IF
CENTER FREQ control. Measured over the
center 8 divisions of the graticule.
Linearity
±3% (over an 8 divisions display)
Resolution
≤1
kHz to
≥100
k H z ; i n 1 1 u n c a l i b r a t e d
May be coupled with the DISPERSION con-
steps.
trol or switched separately.
IF Center Frequency
C o n t r o l R a n g e ”
I F C E N T E R F R E Q
F I N E
1 kHz/DIV to 500 kHz/DIV
Dispersion
≥(+
a n d – 2 . 5 M H z )
≥(+
a n d – 5 0 k H z )
0.2 MHz/DIV to 5 MHz/DIV
≥(+
a n d – 2 5 M H z )
≥(+
a n d – 1 M H z )
10 MHz/DIV
≥(+
a n d – 1 0 M H z )
≥(+
a n d – 1 M H z )
IF Attenuation
Range
0 to 51 dB
In combinations of 1, 2, 4, 8, 16 and 20 dB.
Accuracy
± 0 . 1 d B / d B
IF GAIN Control
Range
≥50
d B
Display Flatness with IF CENTER
3 dB maximum amplitude variations from
Band 1 (10 MHz to 275 MHz) 50 MHz dis-
FREQ at 000
10 MHz to 12.4 GHz.
persion.
6 dB maximum amplitude variations from
Bands 2 through 8 (275 MHz to 40 GHz]
12.4 GHz to 40 GHz
100 MHz dispersion.
Incidental FM
IF
≤ 2 0 0
H z
Typically 100 Hz. Up to 400 Hz if power
line frequency drops to 48 Hz.
IF + LO
≤300
H z ( a t L O f u n d a m e n t a l a n d w i t h
phase lock operation)
Phase Lock
Internal Markers
1 MHz ±0.1% (Control next to OFF posi-
tion.)
INT REF FREQ Range
At least 1 kHz but not more than 1.3 kHz
above measured frequency with the INT
REF FREQ control counterclockwise (next to
OFF position.)
Stability; Ref. Osc.
≤ 1
p o r t i n 1 0
7
.
(Short term FM)
External Phase Lock
Reference Input
Frequency
1 MHz to 5 MHz
Voltage
1 to 5 volts peak to peak.
Display Functions
Dynamic Range
L O G
L I N
S Q L A W
Maximum Input Power
≥40
dB with 8 division display
≥26
dB with 8 division display
Instrument must be inside the dust cover.
≥13
db with 8 division display
- 3 0 d B m f o r l i n e a r o p e r a t i o n
See Fig. 2-8
+15 dBm diode mixer, power limit
1-2
Summary of Contents for 491
Page 4: ...i i Fig 1 1 The Type 491 Spectrum Analyzer ...
Page 24: ...2 16 Fig 2 17 Control set up chart ...
Page 34: ...Fig 3 1 Function block diagram of the Type 491 3 2 ...
Page 42: ...Fig 3 10 Block diagram of the video detector and vertical amplifier 3 1 0 ...
Page 48: ......
Page 53: ...Fig 4 4 Power Supply Circuit board assembly with wiring color code 4 5 ...
Page 54: ...Fig 4 5 Horizontal Display circuit board assembly showing color code to pin connectors 4 6 ...
Page 55: ...Fig 4 6 IF Control board assembly Wiring color code to pin connector 4 7 ...
Page 64: ...Fig 4 20A Tube subassembly removal procedure 4 16 ...
Page 65: ...Fig 4 20B Tube subassembly installation procedure 4 17 ...
Page 68: ...Fig 4 22 Power supply board assembly with component call out 4 2 0 ...
Page 69: ...Fig 4 23 Vertical Amplifier and Blanking board assembly with component call out 4 21 ...
Page 70: ...Fig 4 24 IF control board assembly with component call out 4 22 ...
Page 71: ...Fig 4 24 IF control board assembly with component call out 4 23 ...
Page 72: ...Fig 4 25 Horizontal display board with component call out 4 24 ...
Page 73: ...Fig 4 25 Horizontal display board with component call out 4 25 ...
Page 74: ...Fig 4 26 Phase lock board with component call out 4 26 ...
Page 88: ......
Page 90: ...Fig 6 1 Test equipment recommended for calibration of the Type 491 6 2 ...
Page 138: ......
Page 192: ......
Page 195: ...SECTION II B 3 ...
Page 196: ......
Page 200: ......
Page 201: ...SECTION 9 DIAGRAMS MECHANICAL PARTS LIST ILLUSTRATIONS ACCESSORIES ...
Page 202: ......
Page 203: ...9 1 ...
Page 204: ...9 3 ...
Page 205: ...9 5 ...
Page 206: ...9 7 ...
Page 207: ...9 9 ...
Page 208: ...9 11 ...
Page 209: ...9 13 ...
Page 210: ...9 15 ...
Page 211: ...9 17 ...
Page 212: ...9 19 ...
Page 213: ...9 21 ...
Page 214: ...9 23 ...
Page 215: ...9 25 ...
Page 216: ...9 27 ...
Page 217: ...FIG 1 9 29 ...
Page 218: ...FIG 2 REAR 9 31 ...
Page 219: ...9 33 FIG 3 IF CHASSIS PHASE LOCK ASSEMBLIES ...
Page 220: ...FIG 4 POWER CHASSIS 9 35 ...
Page 221: ...FIG 5 TIME DIV SWITCH OSCILLATOR ASSEMBLIES 9 37 ...
Page 222: ...FIG 6 CRT SHIELD ASSEMBLY 9 39 ...
Page 223: ...FIG 7 CABINET ASSEMBLY HANDLE 9 4 1 ...
Page 224: ...FIG 8 491 STANDARD ACCESSORIES FIG 8 491 STANDARD ACCESSORIES 9 43 ...
Page 225: ......
Page 226: ...PIN 028017 000 ...