User Manual

SGD-SB2025NT-TUM, Part 1
Jan 12 Page 33 TECHNICAL DESCRIPTION
Table 14. 100 W PA Banding Information.
100 W Wide Band PA
Model Frequency Coverage
A3V 39 MHz – 47 MHz
ABV 66 MHz – 88 MHz
CDV 135 MHz – 175 MHz
FV 217 MHz – 222 MHz
NWV 400 MHz – 435 MHz
OWV 435 MHz – 470 MHz
PWV 450 MHz – 495 MHz
5.4 M ICRO C ONTROLLER B OARD
The SB2025 Micro Controller Board has four main functions:
• Overall radio management.
• Tx and Rx signal processing.
• RF power control.
• User interface.
5.4.1 Overall Radio Management
In addition to analogue signal processing circuitry, the Micro Controller board accommodates an
80C552 microprocessor IC1, a 64 kb Erasable Programmable Read-Only Memory (EPROM) IC3,
32 kb Random Access Memory (RAM) IC4, a 16 kb Electrically Erasable Programmable Read
Only Memory (EEPROM), as well as address decoding, I/O latches and other miscellaneous
circuitry. The Micro Controller is responsible for ensuring that the radio acts as programmed by the
user. It stores the user-entered parameters for each channel in the EEPROM. This information
includes Rx and Tx RF frequencies; Rx and Tx CTCSS frequencies, as well as RF output power
and operating mode. An eight channel analogue to digital converter allows the microprocessor to
read eight analogue values internal to the radio, which, in conjunction with the digital inputs to the
microprocessor, allow the operating status of the radio to be monitored and controlled.
The analogue items that are read are listed below in Table 15.
Table 15. Microprocessor Port Parameters.
Port Parameter
ADC0 Received Signal Strength Indication (RSSI)
ADC1 Detected Discriminator Output Level
ADC2 DC Operating Voltage
ADC3 Rx VCO Tuning Voltage
ADC4 Tx VCO Tuning Voltage
ADC5 PA Temperature
ADC6 PA Forward Power
ADC7 PA Reflected Power