Radio Part - Siemens C45 Repair Documentation

4 Radio Part

The radio part of the C45, M50 AND MT50 consists of a Hitachi RF chip-set.
The radio part is designed for Dual Band operation, covering EGSM900 as well
as GSM 1800 frequencies, and can be divided into 4 Blocks.
Power supply for RF-Part
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Transmitter
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Receiver
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Synthesizer,
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The RF-Part has it´s own power supply realised by a voltage regulator
which is directly connected to the battery. The voltages for the logic part are
generated by the Power-Supply ASIC
The transmitter part converts the I/Q base band signals supplied by the
logic (EGOLD+) into RF-signals with characteristics as defined in the
GSM recommendation (www.etsi.org) After amplification by a power
Amplifier the signal is radiated via the internal or external antenna.
The receiver part converts the received GMSK signal supplied by the
antenna into IQ base band signals which can then be further processed by
the logic (EGOLD+).
The synthesizer generates the required frequencies for the transmitter and
Receiver. A 26MHz oscillator is acting as a reference frequency.
Restrictions:
The mobile phone can never transmit and receive in both bands simultaneously.
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Only the monitor time slot can be selected independently of the frequency band.
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Transmitter and receiver can of course never operated simultaneously.
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V1.0
C45, M50 AND MT50
Page 6 of 46
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ICM MP CCQ ST
05/02