Dimetra EBTS » History » Version 5
laforge, 02/21/2016 08:03 AM
1 | 4 | laforge | {{>toc}} |
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2 | 1 | laforge | |
3 | 4 | laforge | h1. Motorola Dimetra EBTS |
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6 | 1 | laforge | The Motorola Dimetra EBTS is a TETRA Base Station design. |
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8 | We have been able to get our hands on some of them. This page documents our knowledge about the units, their configuration and how to use them. |
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11 | 4 | laforge | h2. Hardware |
12 | 1 | laforge | |
13 | 4 | laforge | |
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15 | h3. Motorola Dimetra Base Radio (T5931A) |
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18 | 1 | laforge | The Base Radio (BR) is a modular design in a 4U case, consisting of the following modules: |
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21 | 4 | laforge | h4. Power Supply (CPN1031B) |
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24 | 1 | laforge | As the name suggests, it is merely a power supply, converting from the 48 V input to the various voltages required within the radio |
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27 | 4 | laforge | h4. Controller (CAE010CMX) |
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30 | This is s small [[PowerPC]] based embedded system. It communicates with the TETRA Site Controller (TSC) over 10-Base-2 Ethernet |
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31 | 1 | laforge | and controls all the other units of the Base Radio via the backplane of the BR cabinet. |
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33 | It has the following connections: |
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34 | 4 | laforge | * RS-232 on the back of the BR |
35 | * RS-232 on the front of the BR |
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36 | * Site Alarm I/O on the back of the BR |
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37 | * 10-Base-2 Ethernet on the back of the BR (BNC) |
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38 | * Clock input on the back of the BR (BNC) |
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39 | 1 | laforge | |
40 | 4 | laforge | For more details see [[[Dimetra_EBTSBase_RadioController]]] |
41 | 2 | laforge | |
42 | 1 | laforge | |
43 | 4 | laforge | h4. 3x Diversity Receiver (CTX1090A) |
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46 | 1 | laforge | This is the receiver. It has three antenna inputs in order to use antenna diversity for additional signal gain. |
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48 | The received and demodulated TETRA bursts are forwarded to the Controller via the BR backplane. |
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50 | 4 | laforge | For more details see [[[Dimetra_EBTSBase_RadioReceiver]]] |
51 | 1 | laforge | |
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53 | 4 | laforge | h4. Exciter (CLN1510A) |
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56 | 1 | laforge | This is the transmitter. It receives TETRA frames from the Controler via the backplane and encodes/modulates them. The output |
57 | is fed into the power amplifier over a SMA jumper connection on the back of the base radio. |
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59 | 4 | laforge | For more details see [[[Dimetra_EBTSBase_RadioExciter]]] |
60 | 1 | laforge | |
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62 | 4 | laforge | h4. Power Amplifier (CTX1030A) |
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65 | 1 | laforge | This is a RF power amplifier, used to generate a high-power signal from the output of the exciter. |
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67 | It has three coaxial connections on the back, which are used as follows: |
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68 | 4 | laforge | * input from the exciter |
69 | * feedback from PA into the exciter |
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70 | * actual RF power output (towards antenna) |
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71 | 1 | laforge | |
72 | 4 | laforge | For more details see [[[Dimetra_EBTSBase_RadioAmplifier]]] |
73 | 1 | laforge | |
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75 | 4 | laforge | h3. Integrated Site Controller (CLN1480A) |
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78 | 1 | laforge | This is a unit that interfaces up to 8 Base Radios with the core network of the Dimetra TETRA network (SwMI). |
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80 | 4 | laforge | Hardware-wise, it is a [[PowerPC]] based system, looking very much like an old-fashioned PC mainboard with |
81 | 1 | laforge | both ISA and PCI slots. |
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83 | 4 | laforge | The mainboard houses the [[PowerPC]] CPU and it has slots for RAM. |
84 | 1 | laforge | |
85 | There are some extension cards plugged into the system: |
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86 | 4 | laforge | * Clock generation card (ISA, full length). |
87 | ** has an integrated GPS receiver, to which you attach a GPS antenna |
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88 | ** generates the reference 5MHz clock distributed over Coaxial cable to the Base Radios |
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89 | * Ethernet Card using DEC tulip chipset (PCI) |
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90 | ** This card is what talks to the Base Radios (BR) via 10-Base-2 |
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91 | * Unknown card with RJ-45 jack (REDUND) on the back. Might be E1 |
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92 | 1 | laforge | |
93 | There are further inputs and outputs on the system: |
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94 | 4 | laforge | * A DB-15 jack for X.21 synchronous serial backhaul (2048Mbps) |
95 | * FIXME |
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96 | * A RS-232 serial port for local configuration |
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97 | 1 | laforge | |
98 | 4 | laforge | For more details see [[[Dimetra_EBTSSite_Controller]]] |
99 | 1 | laforge | |
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101 | 4 | laforge | h3. RF Distribution System (CFX4041A) |
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104 | 1 | laforge | This is a sophisticated combiner for the high-power output signals of the PA of up to 4 Base Radios. |
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106 | In order to ensure optimal impedance matching, the combiner is mechanically tuned by electrical motors |
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107 | which are controlled by some control logic. |
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109 | 4 | laforge | The combiner inside the system has the following connections (external connections in *bold*): |
110 | * *4 high-power radio input ports* (N socket on the front, one close to each motor) |
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111 | ** this is where the RF signal emitted by the PA of the BR enters |
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112 | * 4 RF taps, one for each of the high-power radio inputs |
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113 | ** they are connected to the controller unit attached to the inside of the front lid |
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114 | * 1 high-power radio output port (N socket) |
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115 | ** this output is connected to a power meter inside the same cabinet |
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116 | * 4 stepper motor electrical connections |
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117 | ** connected to the controller unit attached to the inside of the front lid |
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118 | * RS-232 serial line for control+monitoring |
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119 | ** this is a DB-9 port of the controller unit attached to the inside of the front lid |
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120 | ** interconnected to one of the Base Radios (typically BR1) inside the rack |
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121 | 1 | laforge | |
122 | The flow of the signals is as follows: |
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123 | 4 | laforge | * RF from the PA enters at the four combiner inputs |
124 | * combined RF output leaves through central output of the combiner, from where |
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125 | * it is routed to the FR power meter |
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126 | * whose output socket is routed to the transmit antenna (or a duplexer in case of a shared Rx/Tx antenna) |
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127 | 1 | laforge | |
128 | 5 | laforge | {{graphviz_link() |
129 | 1 | laforge | digraph G { |
130 | graph [ rankdir = LR ]; |
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131 | |||
132 | //{ rank=same; combiner; controller; }; |
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133 | |||
134 | br1_pa_out -> combiner |
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135 | br2_pa_out -> combiner |
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136 | br3_pa_out -> combiner |
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137 | br4_pa_out -> combiner |
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138 | |||
139 | combiner -> power_meter |
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140 | power_meter -> tx_antenna |
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141 | |||
142 | combiner -> controller [ dir=both color=red ] |
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143 | power_meter -> controller [ color=red ] |
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144 | |||
145 | power_meter [ shape=box ]; |
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146 | combiner [ shape=box ]; |
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147 | controller [ shape=box ]; |
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148 | } |
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149 | 5 | laforge | }} |
150 | 1 | laforge | |
151 | h3. Rx LNA Multicoupler (CRX102A) |
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152 | 4 | laforge | |
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154 | The purpose of the Rx LNA multicoupler is to amplify the received signal from the antennas, and split |
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155 | 1 | laforge | the signal so each Base Radio is attached to each antenna: |
156 | 4 | laforge | |
157 | 5 | laforge | {{graphviz_link() |
158 | 1 | laforge | digraph G { |
159 | graph [ rankdir = LR ]; |
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160 | |||
161 | antenna1 -> lna1 |
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162 | antenna2 -> lna2 |
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163 | antenna3 -> lna3 |
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164 | |||
165 | lna1 -> multicoupler1 |
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166 | lna2 -> multicoupler2 |
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167 | lna3 -> multicoupler3 |
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168 | |||
169 | multicoupler1 -> br1_rx1 |
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170 | multicoupler1 -> br2_rx1 |
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171 | multicoupler1 -> br3_rx1 |
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172 | multicoupler1 -> br4_rx1 |
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173 | |||
174 | multicoupler2 -> br1_rx2 |
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175 | multicoupler2 -> br2_rx2 |
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176 | multicoupler2 -> br3_rx2 |
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177 | multicoupler2 -> br4_rx2 |
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178 | |||
179 | multicoupler3 -> br1_rx3 |
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180 | multicoupler3 -> br2_rx3 |
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181 | multicoupler3 -> br3_rx3 |
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182 | multicoupler3 -> br4_rx3 |
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183 | |||
184 | lna1 [ shape=box label="LNA 1" ]; |
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185 | lna2 [ shape=box label="LNA 2" ]; |
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186 | lna3 [ shape=box label="LNA 3" ]; |
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187 | multicoupler1 [ shape=box ]; |
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188 | multicoupler2 [ shape=box ]; |
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189 | multicoupler3 [ shape=box ]; |
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190 | } |
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191 | 5 | laforge | }} |