Siemens SL55 - Page 23

Customer Care
V 1.0 Page 23of 52 ICM MP CCQ GRM
SL55
Company Confidential © Copyright Siemens AG
06/03
Measurement of Battery and Ambient Temperature
The battery temperature is measured via the voltage divider R1387, R138 by the EGOLD+
(Analog Interface P2). For this, the integrated SD converter of the RX-I base band branch is
used. This SD converter compares the voltage of TBAT and TENV internally. Through an
analogue multiplexer, either the RX-I base band signal, or the TBAT signal and the TENV
signal is switched to the input of the converter. The signal MEAS_ON from the
EGOLD+
(GSM TDMA-TIMER H15) activates the battery voltage measurement The ambient
temperature TENV is measured directly at of the EGOLD+
(Analog Interface P3).
Measurement of the Battery Voltage
The measurement of the battery voltage is done in the Q-branch of the EGOLD+, for this
BATT+ is connected via a voltage divider R143, R146 to the EGOLD+
(Analog Interface P1).
An analogue multiplexer does the switching between the baseband signal processing and
the voltage measurement.
A/D conversion of MIC-Path signals incl. coding
The Microphone signals (MICN2, MIP2, MICP1, MICN1) arrive at the voiceband part of
the EGOLG+. For further operations the signals will be converted into digital information,
filtered, coded and finally formed into the GMSK-Signal by the internal GMSK-Modulator.
This so generated signals (RF_I, RF_IX, RF_Q, RF_QX) are given to the Bright IC in the
transmitter path.
D/A conversion of EP-Path signals incl. decoding
Arriving at the baseband-Part, the demodulated signals (RF_I, RF_IX, RF_Q, RF_QX) will
be filtered and A/D converted. In the voiceband part after decoding (with help of the µC
part) and filtering, the signals will be D/A converted amplified and given as (EPP1_FIL,
EPN1_FIL) to the Power Supply ASIC.