Siemens S55 Repair Documentation page 26

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.
Generation of the PA Control Signal (PA_RAMP)
The RF output power amplifier needs an analogue ramp up/down control voltage. For
this the system interface on EGOLD+ generates 10 bit digital values which have to be
transferred serially to the power ramping path. After loading into an 10 bit latch the
control value will be converted into the corresponding analogue voltage with a
maximum of ~2V
Key-Value
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