ACCEPTANCE TESTING
5-1-36
VOR waveform depth accuracy
SPECIFICATION
±3% of setting ±0.5% for carrier frequencies up to 400 MHz
TEST EQUIPMENT
Description Minimum
specification
Example
Modulation meter
Freq range to 400 MHz
Aeroflex 2305
AM accuracy ±1% of reading
Selectable ILS filter
(1)
Connect the test equipment as shown in Fig. 5-1-22.
(2)
Set up the test equipment as follows:-
Unit under test
VOR mode
Carrier freq
108 MHz
RF level
7 dBm
SUB depth
0 %
REF depth
0 %
Modulation meter
Freq tune
108 MHz
Function AM
Second function 28
On
(3)
With SUB and REF set to 0% measure the residual AM noise. Note the reading.
Residual AM noise depth
____________%
(4)
On the UUT select a SUB depth of 30% and a REF depth of 0%. Allow the
reading on the modulation meter to settle and note it.
Measured AM depth
____________%
Actual SDM = Measured AM depth - Residual AM noise
Minimum Actual Maximum
28.60%
______%
31.40%
Ensure that the measured depth is in specification.
(5)
Repeat (4) for a SUB depth of 0% and a REF depth of 30%.
Minimum Actual Maximum
28.60%
______%
31.40%
(6)
Repeat (4) for a SUB depth of 30% and a REF depth of 30%).
Minimum Actual Maximum
57.70
______%
62.30%
