Rohde & Schwarz EVSG-B1, User Manual

Page: 54 / 418

Numeric Measurement Modes
R&S
®
EVSG1000
54 User Manual 1178.6227.02 ─ 06
4 Numeric Measurement Modes
● ILS Localizer and ILS Glidepath (GP) Modes ......................................................... 54
● ILS Marker Beacon Mode (Option R&S EVSG-K3) ................................................ 87
● VOR Mode (Option R&S EVSG-K2) ....................................................................... 97
● COM Mode (Option R&S EVSG-K6) ..................................................................... 118
● Non-Directional Beacon Mode (Option R&S EVSG1-K7) ..................................... 128
4.1 ILS Localizer and ILS Glidepath (GP) Modes
Access : [Mode] > "ILS LOC"/ "ILS GP"
Access VNC : [m] > Down arrow key
The ILS Localizer and Glidepath measurements demodulate the AM components of
the ILS signal and calculate characteristic parameters such as the modulation depth
and frequency or phase for specific components. Furthermore, an FFT is performed on
all components of the AF signal. The resulting AF spectrum allows you to measure the
required components and their distortions (harmonics).
Using the option R&S EVSG1-K7, you can also analyze the AF components of the ILS
signal to determine AF parameters of the carrier.
Furthermore, you can use the LF input to measure signals with a very low intermediate
frequency (<25
kHz). Such signals are provided as output at test points of a transmit-
ter, for example, for tuning purposes.
Remote command:
MODE_LOC
on page 273
MODE_GP
on page 273
● Localizer Basics ...................................................................................................... 54
● Glide Slope Basics ..................................................................................................55
● ILS Localizer and Glidepath Measurements and Results ....................................... 56
● ILS Localizer and Glidepath Configuration ..............................................................75
4.1.1 Localizer Basics
The localizer transmitter is located near the end of the runway (nearest to the start of
the aircraft approach). Typically, horizontally aligned antennas transmit two intersecting
main beams beside one another at carrier frequencies between 108
MHz and
112 MHz. As seen from the approaching aircraft coming in for a landing, the left beam
is usually modulated at 90 Hz and the right beam at 150 Hz.
The information on position is provided after demodulation of the beam signals by eval-
uating the difference in depth of modulation (DDM).
DDM = m(x90) – m(x150)
ILS Localizer and ILS Glidepath (GP) Modes