An aircraft is on course on an ILS Localiser. What is the depth of modulation?
- zero
- 20%
- 50%
Explanation
The localiser radiates 90 Hz and 150 Hz tones; when the aircraft is exactly on the centreline both are received equally, so the difference in depth of modulation (DDM) is zero. A non-zero DDM only appears as the aircraft moves off the runway centreline towards one side.
nairs asking:
depth of mod zeroooo??
Community Comments (3)
A
alarlns Posts: 4 30.03.2014 / 08:38
20% is right
A
alarlns Posts: 4 10.04.2014 / 13:50
I think that what was meant to be asked in this question is the difference of modulation of 150 Hz and 90 Hz tone if the aircraft was on the the center line. If the aircraft was on course on a ILS Localizer, then the difference in depth modulation on is zero.
J
Jordi Posts: 198 09.04.2021 / 11:48
Guys it says on the books of my part15 organisation,that when the a/c in on couse with the localizer there is no depth and thus 0 modulation.
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