1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-287A 58 W 7779711 0020071 2 W OFFICE OP THE ASSISTANT SECRETARY OF DEFENSE Supply and ILOgitics Test Signals for Electronic Tactical Air Navigation Equipment (TACAN) MIL-STD-287A 1. This standar
2、d has been approved by the Department of Defense and is mandatory or use by the Departments of the Army, the Navy, and the Air Force, effective immediately, 2. In accordance with established procedure, the Standardization Divison has designated the Signal Corps, the Bureau of Aeronautics, and the Ai
3、r Force, refjpectively, as Army-Navy-Air Force custodians of this standard, 3. Recommended corrections, additions, or deletions should be ad- dressed to the Standardization Division, Office of the Asistant Secretary of Defense. (Supply and Logistics), Washington 25, D. C. Provided by IHSNot for Resa
4、leNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-27A 58 7777711r 0020073 b U INTERROGATING CHANNEL FREQ. (Ne) 67 1091 68 1092 69 1093 70 1094 71 1095 72 1096 73 1097 74 109
5、8 76 1059 76 1100 77 1101 78 1102 . 79 1103 80 1104 81 1105 82 1196 83 1107 84 1108 85 1109 86 1110 87 1111 88 1112 89 1113 90 1114 91 1115 92 1116 98 1117 94 1118 95 1119 96 1120 REPLY FREQ. (MC) 2.1.1 Number of ch.annels. There shall be i26 channels provided, numbered 1 through 126. Each channel s
6、hall have: (a) An interrogating frequency. (b) A reply frequency. 2.1.1.1 Interrogating frequency. The inter- rogating frequency shall begin with channel . 1 at 1025 mc and increase in 1 mc incre- ments until channel 126 at 1160 mc is reached. 2.1.1.2 Rsplv fTequencp. The reply fre- quency shall beg
7、in with channel I at 962 mc (which is 63 mc Zozoes. than the interro- gating frequency) and increase in 1 mc in- crements until channel 63 is reached at 1024 mc. Continuing with channel 64 at a reply frequency of 1151 mc (which is 63 1154 1155 1156 1157 *U58 1159 1160 1161 1162 1163 1164 1165 1166 1
8、167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1174 1178 1179 1180 1181 1182 1183 INTERROGATING CHANNEL FREQ. (Mc) 97 1121 98 1122 99 1123 100 1124 101 1125 102 1126 103 1127 104 1128 105 1129 106 1130 107 1131 108 1132 109 1133 110 1134 111 1135 112 1136 113 1137 li4 1138 115 1139 116 1140 117 11
9、41 118 1142 119 1143 120 1144 121 1145 122 1146 123 1147 124 1148 125 1149 126 1150 REPLY FREQ. (Mc) 1184 1185 1186 1189 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 mc higher than the interrogating frequency) and i
10、ncrease in 1 mc increments until chan- nel 126 is reached at 1213 mc. 3. CHARACTERISTICS OF THE TA- CAN TEST SIGNAL POR AIR- The Airborne Tacan equipment shall be tested with a signal having the following characteristics. 3.1 Radio frequency. The frequency of the signal generator oscillator shall be
11、 maintain- ed within * 0.005% of its specified fre- quency. 3.2 R-F pulse spectrum. The energy level contained in a 0.5 mc band centered on a frequency I: 0.8 mc from the channel fre- quency; shall be at least 25 db below the BORNE EQUIPMENT Provided by IHSNot for ResaleNo reproduction or networking
12、 permitted without license from IHS-,-,-energy level contained in a 0.5 mc band cen- tered on the channel frequency. The energy level contained in a 0.5 mc band centered on a frequency therefore, these pulses shall not ap- pear during a Main or Auxiliary Reference Group. 3.8 Identification test sign
13、al, The identifi- cation signal shall consist of a series of pair- ed pulses transmitted at a repetition rate of I350 pulse pairs per second, phase-locked within =r: Ei0 microseconds of the tenth harmonic of the 135 cycle reference bearing signal. The first puise of an identity pair shall occur 740
14、the spaces between dots and dashes being occupied by random pulses, The dots shall be 0.125 =1: 10% sec- onds long; dashes shall be 0.375 * 10% seconds long, Key-down time per identity cycle shall not be less than 4 seconds out.of 7.5 seconds, repeated every identity cycle. 3.9 Pulse repetition rate
15、. In addition to the reference pulse groups, the signal shall have a randomly distributed pulse. repetition rate which shall be maintained at 2700 rt: 90 pairs per second before the reference groups are added to the signal; the random rate may include distance replies. The minimum spacing between an
16、y two consecutive ran- dom pulse pairs shall be 60 r+ 10 microsec- onds. The distribution of the random pulse spacing, for no interrogation load, shall fall within the limits shown in the graph,.fig- Ure 1. 3.10 Composite 15 and 135 cycle variable bearing test signal. The 15 and 135 cycle bearing si
17、gnal shall be generated by the composite amplitude modulation of the radio- frequency pulse signals at 15 and 135 cycles per second. The combined amplitude modula- tion percentage shall be as given in the formula following. The amplitude modula- tion shall be synchronized with the 15 cycle Main Refe
18、rence Group so that, for a bearing of zero degrees, receiver south of the beacon, the 10th puIse of the Main Reference Group will coincide with the positive slope point of inflection of the 15 cycle component of the bearing signal to within The time required for the trailing edge of the pulse to fal
19、l from 90 to 10 “/. of its maximum voltage amplitude shal1 be 2.6 & 1.0 microseconds. 4.3A Pulse wation. The pulse duration, which is measured between the points on the leading and trailing edges of the pulse which are 50% of the maximum voltage amplitude of the pulse, shall be 3.5 * 0.6 microsecond
20、s. 4.4 F&e coding. The pulses shall be coded in pair with a spacing which shall be 12 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-7777711 0020078 5 _- _- MIL-STD-287A !id - - 7 GPO 822932 .- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
