3-13
FREQUENCY
MODULATION TESTS
This procedure verifies the operation of the 691XXB frequency modu-
lation input sensitivity circuitry.
The RF output of the 691XXB is monitored on a Spectrum Analyzer
display. In Unlocked Wide FM mode, the Spectrum Analyzer is used as
a frequency counter to measure the actual FM deviation and deter-
mine FM accuracy. In Unlocked Narrow and Locked FM modes, the
Spectrum Analyzer is used to monitor the carrier level. FM accuracy is
determined by measuring the actual FM sensitivity setting necessary
to reduce the carrier level to its lowest level. These tests qualify how
the FM input signal affects the signal generator’s RF output.
Test Setup
Connect the equipment, shown in Figure 3-8, as fol-
lows:
1. Connect the 691XXB rear panel
10 MHz REF OUT
to the Spectrum Analyzer External Reference In-
put.
2. Connect the Output of the Function Generator to
the 691XXB front panel
FM IN
.
3. Connect the
RF OUTPUT
of the 691XXB to the
Spectrum Analyzer RF Input.
690XXB/691XXB MM
3-31
PERFORMANCE
FREQUENCY
VERIFICATION
MODULATION TESTS
1 0 M H z
R E F O U T
6 9 1 X X B S i g n a l G e n e r a t o r
E X T R E F
I N P U T
R F
O U T P U T
S p e c t r u m A n a l y z e r
R F I N P U T
F u n c t i o n
G e n e r a t o r
O U T P U T
F M
I N
Figure 3-8.
Equipment Setup for the Frequency Modulation Tests
Summary of Contents for 680 C Series
Page 4: ......
Page 5: ......
Page 13: ...Figure 1 1 Typical Series 690XXB 691XXB Synthesized CW Signal Generator Model 69187B Shown ...
Page 61: ......
Page 97: ......
Page 205: ......
Page 207: ......
Page 221: ......
Page 225: ......
Page 241: ......
Page 259: ......
Page 275: ......
Page 285: ......
Page 289: ......
Page 299: ......
Page 303: ......
Page 315: ......