User Manual

SDB670 – SERVICE MANUAL TNM-M-E-0032
May 13 Page 5 CONTENTS
5.1 MMI B OARD ..................................................................................................................... 30
5.1.1 Description ............................................................................................................. 30
5.2 C ONTROL B OARD ............................................................................................................. 30
5.2.1 Circuit Board Layout............................................................................................... 30
5.2.2 Circuit Description .................................................................................................. 31
5.2.2.1 Power............................................................................................................ 31
5.2.2.2 Main Processor ............................................................................................. 31
5.2.2.3 DSP Co-processor ........................................................................................ 31
5.2.2.4 Ethernet Interface.......................................................................................... 31
5.2.2.5 Radio Interface.............................................................................................. 31
5.2.2.6 USB A ........................................................................................................... 31
5.2.2.7 USB B ........................................................................................................... 31
5.2.2.8 Digital I/O ...................................................................................................... 31
5.2.2.9 Fan Control ................................................................................................... 31
5.2.2.10 Analogue Outputs ......................................................................................... 31
5.2.2.11 Analogue Inputs ............................................................................................ 32
5.2.2.12 GPS Input ..................................................................................................... 32
5.2.2.13 External Power.............................................................................................. 32
5.2.2.14 RS232 Serial Interface (DB9) ........................................................................ 32
5.2.2.15 Expansion Header......................................................................................... 32
5.3 T RANSMITTER AND R ECEIVER M ODULES ............................................................................ 32
5.3.1 Control ................................................................................................................... 32
5.3.1.1 DSP and FPGA............................................................................................. 32
5.3.1.2 DSP Clock Oscillator..................................................................................... 33
5.3.1.3 Analogue Inputs and Outputs........................................................................ 33
5.3.1.4 Flash Memory ............................................................................................... 33
5.3.2 Receiver................................................................................................................. 34
5.3.2.1 Front End Filters and RF Amplifier ................................................................ 34
5.3.2.2 Mixer and IF Section ..................................................................................... 34
5.3.2.3 IF Analogue to Digital Convertor ................................................................... 35
5.3.3 Transmitter............................................................................................................. 35
5.3.3.1 Drivers and PA Stages.................................................................................. 35
5.3.3.2 Power Control ............................................................................................... 36
5.3.3.3 Antenna Switch and Harmonic Filter ............................................................. 36
5.3.3.4 Temperature Sensor ..................................................................................... 36
5.3.4 Frequency Synthesiser........................................................................................... 37
5.3.4.1 General ......................................................................................................... 37
5.3.4.2 Fractional PLL............................................................................................... 37
5.3.4.3 Negative Bias Generator and Loop Filter ...................................................... 37
5.3.4.4 Reference Oscillator...................................................................................... 37
5.3.4.5 VCO’s ........................................................................................................... 38
5.3.5 Audio Processing ................................................................................................... 38
5.3.5.1 Receiver Audio.............................................................................................. 38
5.3.5.2 Transmitter Audio.......................................................................................... 39
5.3.6 Power Supplies ...................................................................................................... 39
5.3.6.1 Power On/Off Function.................................................................................. 39
5.3.6.2 Radio Power Supplies................................................................................... 40
6 MAINTENANCE .................................................................................................................. 43
6.1 T ORQUE S ETTINGS ........................................................................................................... 43
6.2 D ISASSEMBLY .................................................................................................................. 43
6.2.1 To Remove the Base from a Rack.......................................................................... 43
6.2.2 To Open the SDB670............................................................................................. 43
6.2.3 To Remove the Tx Assembly ................................................................................. 43