Keysight EXG and MXG X-Series Signal Generators User’s Guide
153
Avionics VOR/ILS (Option 302)
Using ILS Marker Beacon Softkeys
Using ILS Marker Beacon Softkeys
An ILS [Instrument Landing System] is a navigation system, used by aircraft to
obtain guidance to a runway (performing a “runway approach”) and includes
the following three functions operating in tandem (working together):
— ILS Localizer - ensures that the lateral/horizontal left-right approach of an
aircraft is aligned with the center of a runway
— ILS Glide Slope - ensures that the vertical descent path of an aircraft is
aligned to the proper descent path (~ 3 degrees downwards slope) of a
runway
— ILS Marker Beacons - ensures the proper distance from a runway; the
distances are based on the Outer, Middle, and Inner ILS Marker Beacons
Marker Beacons are used to alert a pilot that an action is needed, such as
checking the aircraft altitude. Marker Beacon information is presented to pilots
by audio and visual information. The ILS Localizer may contain present
information on the Outer, Middle, and Inner ILS Marker Beacons. All ILS Marker
Beacons are broadcast at 75 MHz and are located at specific intervals along an
ILS approach. Each ILS Marker Beacon is identified by specific audio as well as
visual characteristics.
Figure 5-16
ILS Marker Beacon Softkeys
ILS Marker Beacon
Code
Color
Sound
Outer Marker
_ _ _
Blue
400 Hz
two dashes per second
Middle Marker
._._._
Amber
1300 Hz
alternating dot and dash
Inner Marker
. . . .
White
3000 Hz
dots only
- Turns
on
and simulates
the Inner Marker Beacon
(3000 Hz modulation)
- Turns
on
and simulates
the Middle Marker Beacon
(1300 Hz modulation)
- Turns
on
and simulates
the Outer Marker Beacon
(400 Hz modulation)
- Sets a Carrier Frequency by selecting an Index from 1 to 33.
(Default: Index is 17 and corresponds to 75.000 MHz)
- Sets the selected Marker Beacon, different from nominal:
Inner=3000 Hz, Middle=1300 Hz, Outer=400 Hz
(Range: 0 Hz to 10 MHz)
- Sets the amplitude modulation depth
on the Marker Beacon Carrier.
(Range: 0 to 99%)
- Turns
off
all
Marker Beacon signals
