Access:
► | Select "Modulation > config... > DME". The "DME Modulation" dialog contains the channel, pulse pair and trigger parameters, and the parameters for setting the modulation. To measure the "Reply response", use an R&S NRP-Z81 Wideband Power Sensor. |
The remote commands required to define the DME modulation settings are described in "SOURce:DME Subsystem".
Activates the DME modulation
Note: Modulations PULSE, VOR, ILS-GS, ILS-LOC, MKR-BCN, ADF, AM, and internal FM/PhiM are automatically switched off when DME modulation is activated. Also, the pulse generator is automatically deactivated.
The DME modulation signal can be output at the LF connector.
Note: Automatic Level Control is deactivated with DME modulation.
When pulse modulation is activated, the R&S SMA deactivates ALC automatically ("ALC OFF", i.e. switches to "Sample & Hold" state).
The "Sample&Hold" state opens the ALC loop, and disables the automatic control of the output level. The level modulator is set directly.
However, to correct the output level, the R&S SMA executes a "Sample & Hold" measurement after each change of frequency or level settings.
- No attenuator is fitted (frequency option R&S SMA-B103L/B106L)
- "High Power" mode is enabled
- "Auto" mode is enabled, and if the level is in the range of the high power, i.e. the mechanical relay bypass is switched.
The level is decreased by 30 dB during "Sample & Hold" measurement.
Selects the DME modulation mode. The mode determines the signal type that is simulated. The exact timing of the signal for each mode is determined by the selected channel (X or Y, see below).
The timing and shape of the pulses can be freely selected. By default these values are set according to the standard.
"DME Interrogation CH X/Y" | The interrogation signal of the airborne transmitter is simulated. The following graph shows the interrogation signal of channel X. ![]() DME interrogation CH X (Trigger = Auto) 1 = SYNC signal (pulse width 50 ns) 2 = VIDEO signal (active with 50 % pulse width of first DME pulse) 3 = LF Output signal (DME modulation signal) 4 = RF Output signal (measured with external detector) |
"DME Reply CH X/Y" | The reply signal of the ground-based transponder is simulated. The trigger is automatically set to external and the default trigger delay either to 50 µs (channel X) or 56 µs (channel Y) depending on the selected channel. The trigger signal is input via the PULSE EXT connector. The interval between the pulse pairs can be set to a fixed value (repetition rate) or to random generation (pulse squitter). The following graph shows the reply signal of channel X (Trigger = External). In case of a trigger event, the reply pulse pair is generated after the set trigger delay. ![]() DME reply CH X (Trigger = External) 1 = external TRIGGER signal (T: pulse width 50 ns) 2 = SYNC signal (pulse width 50 ns) 3 = VIDEO signal with a delay of 50 µs between external trigger and video signal (= range distance of 0 nm) (active with 50 % pulse width of first DME pulse) 4 = LF Output signal (DME modulation signal) |
Selects the channel that is simulated.
Standard compliant X and Y channels differ in the spacing between the two pulses of the pulse pair and the delay of the ground station (see table below). ICAO indicates the ICAO channel parameter below for selecting the ICAO channel.
Channel | Pulse spacing interrogation mode | Pulse spacing reply mode | Reply delay 1st pulse | Reply delay 2nd pulse |
---|---|---|---|---|
X | 12 us | 12 us | 50 us | 50 us |
Y | 36 us | 30 us | 56 us | 50 us |
Selects the ICAO channel, i.e., the DME transmitting frequency. The RF frequency is set to the value selected here.
- Ch. No. = ICAO channel number
- VOR freq. = VOR interrogation frequency (MHz)
- DME interrog. freq. = DME interrogation frequency (MHz)
- DME reply freq. = DME reply frequency (MHz)
Ch. No. | VOR freq. | DME interrog. freq. | DME reply freq. | Ch. No. | VOR freq. | DME interrog. freq. | DME reply freq. | Ch. No. | VOR freq. | DME interrog. freq. | DME reply freq. | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1X 1Y | 1025 1025 | 962 1088 | 43X 43Y | 110.60 110.65 | 1067 1067 | 1004 1130 | 85X 85Y | 113.80 113.85 | 1109 1109 | 1172 1046 | |||
2X 2Y | 1026 1026 | 963 1089 | 44X 44Y | 110.70 110.75 | 1068 1068 | 1005 1131 | 86X 86Y | 113.90 113.95 | 1110 1110 | 1173 1047 | |||
3X 3Y | 1027 1027 | 964 1090 | 45X 45Y | 110.80 110.85 | 1069 1069 | 1106 1132 | 87X 87Y | 114.00 114.05 | 1111 1111 | 1174 1048 | |||
4X 4Y | 1028 1028 | 965 1091 | 46X 46Y | 110.90 110.95 | 1070 1070 | 1007 1133 | 88X 88Y | 114.10 114.15 | 1112 1112 | 1175 1049 | |||
5X 5Y | 1029 1029 | 966 1092 | 47X 47Y | 111.00 111.05 | 1071 1071 | 1008 1134 | 89X 89Y | 114.20 114.25 | 1113 1113 | 1176 1050 | |||
6X 6Y | 1030 1030 | 967 1093 | 48X 48Y | 111.10 111.15 | 1072 1072 | 1009 1135 | 90X 90Y | 114.30 114.35 | 1114 1114 | 1177 1051 | |||
7X 7Y | 1031 1031 | 968 1094 | 49X 49Y | 111.20 111.25 | 1073 1073 | 1010 1136 | 91X 91Y | 114.40 114.45 | 1115 1115 | 1178 1052 | |||
8X 8Y | 1032 1032 | 969 1095 | 50X 50Y | 111.30 111.35 | 1074 1074 | 1011 1137 | 92X 92Y | 114.50 114.55 | 1116 1116 | 1179 1053 | |||
9X 9Y | 1033 1033 | 970 1096 | 51X 51Y | 111.40 111.45 | 1075 1075 | 1012 1138 | 93X 93Y | 114.60 114.65 | 1117 1117 | 1180 1054 | |||
10X 10Y | 1034 1034 | 971 1097 | 52X 52Y | 111.50 111.55 | 1076 1076 | 1013 1139 | 94X 94Y | 114.70 114.75 | 1118 1118 | 1181 1055 | |||
11X 11Y | 1035 1035 | 972 1098 | 53X 53Y | 111.60 111.65 | 1077 1077 | 1014 1140 | 95X 95Y | 114.80 114.85 | 1119 1119 | 1182 1056 | |||
12X 12Y | 1036 1036 | 973 1099 | 54X 54Y | 111.70 111.75 | 1078 1078 | 1015 1141 | 96X 96Y | 114.90 114.95 | 1120 1120 | 1183 1057 | |||
13X 13Y | 1037 1037 | 974 1100 | 55X 55Y | 111.80 111.85 | 1079 1079 | 1016 1142 | 97X 97Y | 115.00 115.05 | 1121 1121 | 1184 1058 | |||
14X 14Y | 1038 1038 | 975 1101 | 56X 56Y | 111.90 111.95 | 1080 1080 | 1017 1143 | 98X 98Y | 115.10 115.15 | 1122 1122 | 1185 1059 | |||
15X 15Y | 1039 1039 | 976 1102 | 57X 57Y | 112.00 112.05 | 1081 1081 | 1018 1144 | 99X 99Y | 115.20 115.25 | 1123 1123 | 1186 1060 | |||
16X 16Y | 1040 1040 | 977 1103 | 58X 58Y | 112.10 112.15 | 1082 1082 | 1019 1145 | 100X 100Y | 115.30 115.35 | 1124 1124 | 1187 1061 | |||
17X 17Y | 108.00 108.05 | 1041 1041 | 978 1104 | 59X 59Y | 112.20 112.25 | 1083 1083 | 1020 1146 | 101X 101Y | 115.40 115.45 | 1125 1125 | 1188 1062 | ||
18X 18Y | 108.10 108.15 | 1042 1042 | 979 1105 | 60X 60Y | 1084 1084 | 1021 1147 | 102X 102Y | 115.50 115.55 | 1126 1126 | 1189 1063 | |||
19X 19Y | 108.20 108.25 | 1043 1043 | 980 1106 | 61X 61Y | 1085 1085 | 1022 1148 | 103X 103Y | 115.60 115.65 | 1127 1127 | 1190 1064 | |||
20X 20Y | 108.30 108.35 | 1044 1044 | 981 1107 | 62X 62Y | 1086 1086 | 1023 1149 | 104X 104Y | 115.70 115.75 | 1128 1128 | 1191 1065 | |||
21X 21Y | 108.40 108.45 | 1045 1045 | 982 1108 | 63X 63Y | 1087 1087 | 1024 1150 | 105X 105Y | 115.80 115.85 | 1129 1129 | 1192 1066 | |||
22X 22Y | 108.50 108.55 | 1046 1046 | 983 1109 | 64X 64Y | 1088 1088 | 1151 1025 | 106X 106Y | 115.90 115.95 | 1130 1130 | 1193 1067 | |||
23X 23Y | 108.60 108.65 | 1047 1047 | 984 1110 | 65X 65Y | 1089 1089 | 1152 1026 | 107X 107Y | 116.00 116.05 | 1131 1131 | 1194 1068 | |||
24X 24Y | 108.70 108.75 | 1048 1048 | 985 1111 | 66X 66Y | 1090 1090 | 1153 1027 | 108X 108Y | 116.10 116.15 | 1132 1132 | 1195 1069 | |||
25X 25Y | 108.80 108.85 | 1049 1049 | 986 1112 | 67X 67Y | 1091 1091 | 1154 1028 | 109X 109Y | 116.20 116.25 | 1133 1133 | 1196 1070 | |||
26X 26Y | 108.90 108.95 | 1050 1050 | 987 1113 | 68X 68Y | 1092 1092 | 1155 1029 | 110X 110Y | 116.30 116.35 | 1134 1134 | 1197 1071 | |||
27X 27Y | 109.00 109.05 | 1051 1051 | 988 1114 | 69X 69Y | 1093 1093 | 1156 1030 | 111X 111Y | 116.40 116.45 | 1135 1135 | 1198 1072 | |||
28X 28Y | 109.10 109.15 | 1052 1052 | 989 1115 | 70X 70Y | 112.30 112.35 | 1094 1094 | 1157 1031 | 112X 112Y | 116.50 116.55 | 1136 1136 | 1199 1073 | ||
29X 29Y | 109.20 109.25 | 1053 1053 | 990 1116 | 71X 71Y | 112.40 112.45 | 1095 1095 | 1158 1032 | 113X 113Y | 116.60 116.65 | 1137 1137 | 1200 1074 | ||
30X 30Y | 109.30 109.35 | 1054 1054 | 991 1117 | 72X 72Y | 112.50 112.55 | 1096 1096 | 1159 1033 | 114X 114Y | 116.70 116.75 | 1138 1138 | 1201 1075 | ||
31X 31Y | 109.40 109.45 | 1055 1055 | 992 1118 | 73X 73Y | 112.60 112.65 | 1097 1097 | 1160 1034 | 115X 115Y | 116.80 116.85 | 1139 1139 | 1202 1076 | ||
32X 32Y | 109.50 109.55 | 1056 1056 | 993 1119 | 74X 74Y | 112.70 112.75 | 1098 1098 | 1161 1035 | 116X 116Y | 116.90 116.95 | 1140 1140 | 1203 1077 | ||
33X 33Y | 109.60 109.65 | 1057 1057 | 994 1120 | 75X 75Y | 112.80 112.85 | 1099 1099 | 1162 1036 | 117X 117Y | 117.00 117.05 | 1141 1141 | 1204 1078 | ||
34X 34Y | 109.70 109.75 | 1058 1058 | 995 1121 | 76X 76Y | 112.90 112.95 | 1100 1100 | 1163 1037 | 118X 118Y | 117.10 117.15 | 1142 1142 | 1205 1079 | ||
35X 35Y | 109.80 109.85 | 1059 1059 | 996 1122 | 77X 77Y | 113.00 113.05 | 1101 1101 | 1164 1038 | 119X 119Y | 117.20 117.25 | 1143 1143 | 1206 1080 | ||
36X 36Y | 109.90 109.95 | 1060 1060 | 997 1123 | 78X 78Y | 113.10 113.15 | 1102 1102 | 1165 1039 | 120X 120Y | 117.30 117.35 | 1144 1144 | 1207 1081 | ||
37X 37Y | 110.00 110.05 | 1061 1061 | 998 1124 | 79X 79Y | 113.20 113.25 | 1103 1103 | 1166 1040 | 121X 121Y | 117.40 117.45 | 1145 1145 | 1208 1082 | ||
38X 38Y | 110.10 110.15 | 1062 1062 | 999 1125 | 80X 80Y | 113.30 113.35 | 1104 1104 | 1167 1041 | 122X 122Y | 117.50 117.55 | 1146 1146 | 1209 1083 | ||
39X 39Y | 110.20 110.25 | 1063 1063 | 1000 1126 | 81X 81Y | 113.40 113.45 | 1105 1105 | 1168 1042 | 123X 123Y | 117.60 117.65 | 1147 1147 | 1210 1084 | ||
40X 40Y | 110.30 110.35 | 1064 1064 | 1001 1127 | 82X 82Y | 113.50 113.55 | 1106 1106 | 1169 1043 | 124X 124Y | 117.70 117.75 | 1148 1148 | 1211 1085 | ||
41X 41Y | 110.40 110.45 | 1065 1065 | 1002 1128 | 83X 83Y | 113.60 113.65 | 1107 1107 | 1170 1044 | 125X 125Y | 117.80 117.85 | 1149 1149 | 1212 1086 | ||
42X 42Y | 110.50 110.55 | 1066 1066 | 1003 1129 | 84X 84Y | 113.70 113.75 | 1108 1108 | 1171 1045 | 126X 126Y | 117.90 117.95 | 1150 1150 | 1213 1087 |
("Reply Mode" only)
Sets the simulated distance between interrogator and transponder for reply mode. The distance is given in nautic miles (nm). 1 nm is 1852.01 meters and corresponds to a run time of 12.359 µs.
The range distance and the external trigger delay are interdependent according to:
"Range Distance" = ("Trigger Delay" – X/Y mode delay) / 12.359 µs/nm,
where:
X mode delay = 50 µs, Y mode delay = 56 µs
Changing one value automatically changes the other value.
Remote command:The average repetition rate is 2700 pp/s. The pulse spacing is distributed randomly in the range of 60 µs to about 1500 µs according to EUROCAE EN-54 6.2.12.
The squitter pulses are constantly sent by the ground station in order to ensure proper operation and in order to ease synchronization of the aircraft interrogator to the ground station.
Remote command:- In "Interrogation mode"
Sets the pulse repetition rate for trigger setting "Auto" or "Ext Gated". - In "Reply Mode"
Indicates the mean pulse repetition rate in squitter mode.
("Reply Mode" only)
Sets the relation between reply pulse pairs and received trigger signals. E.g. with a set efficiency of 50 % only every second trigger event leads to the generation of a reply pulse pair.
Remote command:Accesses the dialog for setting the trigger parameters (see "Trigger Settings for DME").
("Reply Mode" only)
Accesses the dialog for setting the DME ID signal parameters (see "ID Settings for DME Reply Mode").
Selects the pulse shape.
"Cos^2" | The falling and the rising edge of the pulse are cos^2 shaped. |
"Cos Cos^2" | The rising edge is cos shaped and the falling edge is cos^2 shaped. |
"Linear" | The falling and the rising edge of the pulse are shaped linear. |
Sets the rise time of the pulse (10 % to 90 % of peak voltage).
Remote command:Sets the pulse width (50 % to 50 % of peak voltage).
Remote command:Sets the fall time of the pulse (90 % to 10 % of peak voltage).
Remote command:Sets the spacing between the first and second pulse of a pulse pair. I.e. the time between half-voltage points on the leading edge of each pulse.
Remote command:Activates generation of a single test pulse.
Remote command:("Pulse Squitter > Off" only)
Activates an echo pulse pair. The echo pulses have the same shape and timing as the original pulses.
You can determine the delay and attenuation of the echo pulses, see "Echo Delay - DME Modulation", and "Echo Attenuation - DME Modulation".
Remote command:("Echo Pulse > On" only)
Sets the delay from the first original pulse to the first echo pulse.
Remote command:("Echo Pulse > On" only)
Sets the attenuation of the echo pulses compared to the original pulses. A positive attenuation leads to echo pulses with reduced amplitude compared to the original pulses. A negative attenuation leads to echo pulses with increased amplitude compared to the original pulses.
Remote command:Activates the generation of a DME signal with higher spectral purity but less dynamic compared to the default mode. The ON/OFF ratio of the pulses is reduced from >100 dB to 35 dB typically.
Remote command:("Reply Mode" only)
Accesses the dialog for defining the two-tone signals that can be additionally superimposed on the pulses (see "DME Composite AM Settings").
(Only if an R&S NRP-Z81 power sensor is connected to the R&S SMA sensor connector)
Accesses the dialog for setting the "DME Analysis" (see "DME Analysis").
Sets a default DME signal (interrogation mode channel X).
Selects the default settings for the pulse parameters according to standard (EUROCAE ED57/ED54 and ICAO ANNEX 10 to the convention of international civil aviation).
This button does not impact the modulation state.
Remote command:Activates internal adjustment of the DME pulse slope for best linearity.
Remote command:
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