21
Figure1-22
Startup/shutdown module
8. Battery temperature switchover module
This module converts the thermistor into voltage and sends the voltage to ADC on
the TCPU board to be measured. Thus, the battery temperature will be measured.
See the following figure for the circuit.
Figure1-23
Battery temperature switchover module
1.3.3 MSM6000 Sub-System
The MSM6000 sub-system includes voice coding/decoding unit, baseband signal
processing unit, and CPU system on which protocol software runs. All these
functional units are integrated into the MSM6000 chip. The main function of the
voice coding/decoding unit is to conduct compressing and coding operations over
64K voice and digital code traffics like EVRC codes, to let them be suitable for
being transmitted in wireless environment. The baseband signal processing unit
mainly includes functions like baseband modulation/demodulation and channel
coding/decoding. It also includes the CPU system through which protocol software
runs, as well as FLASH for storing software and SRAM for running software
1.3.4
Radio Frequency Sub-System
For
ETS20XX/ETS22XX/ETS25XX,
the
working
frequency
band
is
450MHz/800MHz1900MHz.
The following chapter will explain the detail description of ETS2000 series FWT
radio frequency sub-system components.
1. Receiving unit
Unit function: After the duplex module sufficiently suppresses the out-of-band
spurious filter, the received radio frequency signals will be sent to the down-convert
frequency mixer via the radio frequency low noise amplifier and radio frequency