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4 Radio Part
The radio part of the A55/C55, is using a Hitachi and an Infineon RF chip-set. This
manual covers the Hitachi chip-set. For Infineon there is an additional manual
available.
The radio part is designed for Dual Band operation, covering EEGSM900 as well as
GSM 1800 frequencies, and can be divided into 4 Blocks.
-Power supply for RF-Part
-Transmitter
-Receiver
-Synthesizer,
The RF-Part has it´s own power supply realised by a voltage regulator which is
located
inside the ASIC. The voltages for the logic part are generated by the Power-Supply
ASIC too.
The transmitter part converts the I/Q base band signals supplied by the
(EGOLD+)
into
RF-signals
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 are 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. Only
the monitor time slot can be selected independently of the frequency band.
Transmitter and receiver can of course never operated simultaneously.
4.1 Power Supply RF-Part
The voltage regulator for the RF-part is located inside the
5.2)
It generates the required 2,8V "RF-Voltages" named
voltage regulator is activated as well as deactivated via
VCXOEN_UC
(Miscellaneous R6)
is used to extend the stand by time.
Circuit diagram
V1.20
A55/C55_Hitachi
with
characteristics
provided by the EGOLD+. The temporary deactivation
Page 6 of 48
Company Confidential © Copyright Siemens AG
as
defined
in
the
ASIC
D361.(see chapter
VCC2_8
and
VCC_SYN
SLEEPQ
(TDMA-Timer H16)
VCC2_8
VCC_SYN
ICM MP CCQ GRM
logic
GSM
. The
and
04/03
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