Motorola Cleartone CM5000 Basic Service Manual page 25

OVERVIEW
System Controller
System Controller consists of System On Chip (SOC), ROM / RAMs, and supply voltage regulator.
The SOC (IC 601) contains Microprocessor (CPU), DSP (Digital Signal Processor) and peripheral
circuit. It is constantly working when the radio unit is turned on. It is sampling the signal cause from
switch operation of the radio and the received control signal from a TRBS which is processed by dig-
ital signal processor circuit.
Once any of these signal lines have been changed the microprocessor knows what to do and then
sends out the control signal to the necessary circuit.
The system program for the Main unit is installed in the Flash-ROM (IC602).
The microprocessor in the SOC copies the program from Flash-ROM to the SDRAM (IC603) when
the radio is powered up. The microprocessor reads the program from SDRAM, and executes the
instructions accordingly.
The radio parameter of the equipment is installed in the free area of the Flash-ROM (IC602).
The temporary data of the equipment is stored in the SDRAM (IC603) and SRAM (IC604). The radio
parameters (e.g. output power adjustment, receiver adjustment) are stored in the EEPROM (IC605).
Digital Signal Processing
Digital signal processing circuit is consist of the following devices.
• Channel CODEC DSP, Voice CODEC DSP and signal processing hardware in the SOC (Sys-
tem On Chip)
• ADC, DAC and Linear CODEC in the AFE (Analog Front End).
• Peripheral 10 bit ADC and 12 bit DAC
Receive Process and Decoding
Received analog signal that is converted to the IF frequency was converted to the digital signal by
the 10 bit ADC and fed to the SOC.
The digital signal is quadrature detected and filtered, then converted to the I/Q signal.
The channel CODEC recover the I/Q signal to the original signal stream by delay detection, and per-
form Channel Decoding.
Then the decoded signal is fed to Voice CODEC in case of voice signal or fed to CPU in case of con-
trol signal or message data.
Transmit Process and Coding
The voice CODEC DSP sends the coded voice data to the Channel CODEC. The CPU sends the
control and message data to the Channel CODEC.
The channel CODEC DSP perform channel encoding and framing the provided signal, then convert
to the I/Q signal.
The I/Q signal is filtered (roll off alpha = 0.35) by the signal processing hardware in the SOC. Then
converted to the analog signal as I/Q signal by the 12 bit DAC.
CM5000 Mobile Repeater/Gateway - Basic Service Manual 11