The "ILS-LOC Modulation" dialog is opened in the "Mod" function block or using the MENU key under "Mod".
In the upper section, the modulation source is selected and the modulation switched on. The configuration of the selected external and/or internal modulation source is performed in the lower section of the dialog.
Activates ILS-LOC modulation.
Activation of ILS-LOC modulation deactivates AM, VOR, ILS-GS, Marker Beacon and ADF modulation.
Source selection is disabled in the "LF Generator / Output" dialog:

Defines the polarity for DDM calculation (see DDM Depth).
Remote command:Enters the arithmetic sum of the modulation depths of the left lobe (90Hz) and right lobe (150Hz) ILS-LOC signal contents. The RMS modulation depth of the sum signal depends on the phase setting of both modulation tones. The sum of Sum of Depth and COM/ID depth must be smaller than 100 PCT.
Remote command:Selects the simulation mode for the ILS-LOC modulation signal. A change of the setting automatically changes the sign of the DDM value.
This setting simulates the direction in which the pilot has to correct the course.
"Left" | The 150-Hz modulation signal is predominant, the DDM value is negative (the airplane is too far to the right, it must turn to the left). |
"Right" | The 90-Hz modulation signal is predominant, the DDM value is positive (the airplane is too far to the left, it must turn to the right). |
Enters the current of the ILS indicating instrument corresponding to the DDM value. The instrument current is calculated according to:
DDM uA = DDM × 967.75 uA
A variation of the instrument current automatically leads to a variation of the DDM value and the DDM value in dB.
Remote command:Enters the difference in depth of modulation between the signal of the left lobe (90 Hz) and the right lobe (150 Hz).
- Polarity 90 Hz - 150 Hz (default setting):
DDM = [ AM(90 Hz) - AM (150 Hz) ] / 100% - Polarity 150 Hz - 90 Hz:
DDM = [ AM(150 Hz) - AM (90 Hz) ] / 100%
A variation of the DDM value automatically leads to a variation of the DDM value in dB and the value of the instrument current.
Remote command:Enters the DDM value in dB. The dB value is calculated according to:
DDM dB = 20 × LOG [(SDM+DDM×100%) / (SDM-DDM×100%)]
A variation of the value automatically leads to a variation of the DDM value and the instrument current.
Remote command:Enters the difference in depth of modulation between the signal of the left lobe (90 Hz) and the right lobe (150 Hz).
- Polarity 90 Hz - 150 Hz (default setting):
DDM = [ AM(90 Hz) - AM (150 Hz) ] - Polarity 150 Hz - 90 Hz:
DDM = [ AM(150 Hz) - AM (90 Hz) ]
A variation of the DDM value automatically leads to a variation of the DDM value in dB and the value of the instrument current.
Remote command:Selects if the DDM value is fixed or is changed with a change of sum of modulation depths (SDM, see below).
"Fixed" | The absolute DDM values stays constant when the SDM is changed. |
"SDM" | The absolute DDM values changes when the SDM is changed. The DDM value expressed in dB stays constant. |
Selects the operating mode for the ILS-LOC modulation signal.
"Norm" | ILS-LOC modulation is active. |
"90 Hz" | Amplitude modulation of the output signal with the left lobe (90Hz) signal component of the ILS-LOC signal. The modulation depth of the 90Hz signal results from the settings of parameters "Sum of depth (SDM)" and "DDM" according to:
|
"150 Hz" | Amplitude modulation of the output signal with the right lobe (150Hz) signal component of the ILS-LOC signal. The modulation depth of the 150Hz signal results from the settings of parameters "Sum of depth (SDM)" and "DDM" according to:
|
Enters the modulation frequency of the antenna lobe arranged at the left viewed from the air plane.
Remote command:Enters the modulation frequency of the antenna lobe arranged at the right viewed from the air plane.
Remote command:Enters the phase between the modulation signals of the left and right antenna lobe. The zero crossing of the right lobe (150Hz) signal serves as a reference. The angle refers to the period of the signal of the right antenna lobe.
Remote command:Activates the ILS-LOC default setting.
Parameter | Value |
---|---|
State | Not affected by Set to default |
Sum of Depth | 40 Percent |
Fly | Up |
DDM | 0 |
Mode | Norm |
Left frequency | 90 Hz |
Right Frequency | 150 Hz |
Left/Right Phase | 0 deg |
COM/ID State | Off |
COM/ID Frequency | 1020 kHz |
COM/ID Period | 9 s |
COM/ID Depth | 10 percent |
Switches on/off an additional communication/identification signal (COM/ID signal).
Remote command:Reveals the detailed setting options for the COM/Id signal. Once the details are revealed, the labeling on the button changes to "Hide Details". Use this to hide the detailed setting options display again. (COM/ID signal).
Remote command:n.a.
Enters the coding of the COM/ID signal by the international short name of the airport (e.g. MUC for the Munich airport). (COM/ID signal).
The COM/ID tone is sent according to the selected code (see table of Morse below).The length of the Morse code can be varied. For selection standard time scheme, the selected dot length determines the setting of all other length parameters of the Morse code (dash length, symbol space and letter space) . For selection user time scheme, all length parameters of the code can be set independently.
If no coding is entered, the COM/ID tone is sent uncoded (key down).
Letter | Morse Code | Letter | Morse Code |
---|---|---|---|
A | . - | N | - . |
B | - . . . | O | - - - |
C | - . - . | P | . - - . |
D | - . . | Q | - - . - |
E | . | R | . - . |
F | . . - . | S | . . . |
G | - - . | T | - |
H | . . . . | U | . . - |
I | . . | V | . . . - |
J | . - - - | W | . - - |
K | - . - | X | - . . - |
L | . - . . | Y | - . - - |
M | - - | Z | - - . . |
- A dot (.) has a tone duration of 100 ms
- A dash (-) has a tone duration of 300ms
- The time between two tones is 100ms
- The time between two letters is 300ms
ID code = MUC
The word length = 300+100+300+300+100+100+100+100+300+300+300+100+100+100+300+100+100 = 3100 ms
Enters the frequency of the COM/ID signals.
Remote command:Enters the period of the COM/ID signal in seconds.
Remote command:Enters the AM modulation depth of the COM/ID signal. The sum of subcarrier depth, VAR depth and COM/ID depth must be smaller than 100 PCT.
Remote command:Selects if the set dot length determines the dash length (= three times the dot length) (setting Standard) or if all length parameters can be set independently (setting User). (COM/ID signal).
Remote command:Enters the length of a Morse dot by means of seconds. The length of the dash (3xdot), space (=dot) and letter space (=3xdot) is also determined by this entry if time scheme standard is selected.
Remote command:(user time schema only)
Enters the length of a Morse dash by means of seconds.
Remote command:(user time schema only)
Enters the length of a symbol space by means of seconds.
Remote command:(user time schema only)
Enters the length of a letter space by means of seconds.
Remote command:Selects the variation of the DDM values via the rotary knob.
"Decimal" | Decimal variation according to the current cursor position. |
"Defined" | Variation in predefined steps according to the standardized DDM values:
|
n.a.
Selects the variation of the carrier frequency via the rotary knob.
Selects the ICAO channel, i.e., the ILS-LOC transmitting frequency. The RF-frequency is set to the value selected here. A variation of the carrier frequency by the rotary knob is performed in predefined steps according to the standardized ILS-LOC transmitting frequencies (see table). The ICAO channel settings for ILS-GS and ILS-LOC are coupled.
Remote command:Changes to ILS-GS modulation and opens the menu. The state of the ILS LOC modulation (On or Off) is also set for ILS-GS. The RF frequency setting automatically changes to the transmitting frequency associated with the set ICAO channel for ILS-GS if the state is on.
Remote command:n.a.
Switching on/off an external modulation. The external signal is input via the AM EXT connector.
"Off" | Selects the internal modulation source for ILS-LOC modulation. |
"EXT (MOD AM)" | Selects the external source. The external signal is added to the internal signal. Switching off the internal source is not possible. The external signal is input via the AM EXT connector. The sensitivity is 10 mV per percent modulation depth.
Note: There can be an overmodulation as a function of the level of the external signal without a corresponding caution message being generated.In order to avoid an overmodulation, the peak value of the external signal is to be delimited corresponding to the sum of the modulation depths of the remaining ILS signal components. |
Imprint | Statement of Privacy | Terms & Conditions | © 2016 ROHDE & SCHWARZ |