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OPTION 006 Avionics
Annex-A-34
VOR waveform test
Test equipment
Description Minimum
specification Example
Spectrum analyzer
or
FFT analyzer
DC to 25 kHz
3 Hz filter
IFR 2382
(1)
Connect the test equipment as shown in Fig. A-29.
(2)
Set up the test equipment as follows:
Unit under test
VOR mode
SUB depth
30%
REF depth
30%
Spectrum analyzer
Span/div 200
Hz
Ref freq
9.96 kHz
Ref level
10 dBm
Bandwidth 30
Hz
(3)
Check that a display similar to that shown in Fig. A-30 is obtained. This shows the
presence of the 9.96 kHz sub-carrier with 30 Hz rate, 480 Hz deviation frequency
modulation present.
C0565
10.0
Atten 50dB 50
Ω
DC TG off
2382
MARCONI
A dB
0.0
-10.0
-20.0
-30.0
-40.0
-50.0
-60.0
-70.0
-80.0
-90.0
Ref 9.960kHz
A
200Hz/div
Res bw
30 Hz
Inc 200Hz
1 s /div
Vid bw
43Hz
Fig. A-30 9.96 kHz sub-carrier with frequency modulation