Sony Ericsson K800, Electrical Repair Manual

Page: 6 / 122

K800 - K810
1202-3085 rev. 2
FUNCTION OVERVIEW
FU
N
C
T
IO
N
O
V
E
R
V
IE
W
2.6 IR
The IR transceiver is IrDA compatible.
2.7 FM radio
The FM radio receiver is a stereo radio able to decode RDS information.
2.7.1 RF part
The FM radio can tune to the US/European broadcast FM frequency band, 87.5 – 108 MHz
2.7.2 Frequency generation
The FM radio receiver uses a 32.768 kHz reference clock to tune the local oscillator.
2.7.3 Receiver
The RF signal to the FM radio is fi rst fed into a low noise ampli fi er. The ampli fi ed signal is then
mixed with the local oscillator. The IF is of low frequency-type.
The signal is then further ampli fi ed, limited and demodulated. The demodulated signal is fed into a
decoding circuitry where the right and left audio signals and RDS information are separated.
2.7.4 Logic part
The logic part of the FM radio controls the frequency tuning system, and various settings within
the FM radio system. It also handles the communication, including transfer of RDS data, with the
CPU of the mobile phone. The communication with the CPU is over a two-wire I
2
C interface.
2.7.5 Antenna
The cord to the portable hands-free headset functions as the antenna for the FM radio.
2.8 External Connectors
External units are connected to the transceiver by means of a 12-pin connector on the bottom of
the phone. The pin numbering is starting from the left when looking at the system connector with
the back of the phone up.
1
Vbus
2
SP
Ref
5
Sp
L
/
DBG
TX
6
Sp
R
/
DBG
RX
4
Mic-
/
Aux in
R
7
Video
/
Strobe
8
AID
/
ACB
/
Vpp
Flash
9
GND
10
D+
/
DTMS
3
Mic+
/
Aux in
L
11
D-
/
DFMS
12
DCIO
Figure 3. System connector pin out
Description
SEMC Electrical Repair Manual
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