Logic/Audio Part; Acrobat Reader 7.0 (Or Later Version) And Enter The Component Name Or Other Word. Use Zoom To Bluetooth - Sony Ericsson K800 Electrical Repair Manual

The TX ASIC is the main component for controlling the power. The VGA is able to handle at least
50dB power dynamic in 1dB steps while the QVGA handles 1dB in 0.25dB steps.
"Buffgain" is a programmable PA buffer in which the bias current is optimized and fi nally is the buffer
possible to be used in low gain mode, which generates about 30dB lower output power compared
with the highest output setting.
The PA has also a variable voltage created by a DC/DC converter. By changing the PA voltage it's
possible to have a better effi ciency and it's done with the reference signal from a DAC.
It's also possible to change the bias current in the PA by tuning a DAC.
By combining the variable voltage and bias current it's possible to have the best current effi ciency
and still cope with the linear performance demands.

2.3 Logic/Audio Part

2.3.1 Functions
The purpose of the logic part is to control and monitor the transmission and reception functions of
the mobile phone and to maintain contact with the mobile phone system. The logic therefore has
links to all the relevant parts of the radio. Its functions, with reference to the radio, include selection
of radio channel and control of the transmitter power and the overall radio timing. It also generates
the base-band modulation after encryption, channel coding and demodulates the received base-
band signal including equalization, decryption and channel decoding.
Its functions, with reference to the audio parts, include volume control of the earphone and
loudspeaker. Speech codec and PCM A/D and D/A are also performed here, together with the
appropriate audio frequency fi ltering.
The external tasks of the logic part include monitoring and control of links with the control unit and
power supply and also the communication to the SIM/USIM and external units connected to the
external connectors.
The Logic/Audio part also includes a 32.768 kHz XTAL used for the real time clock.
2.4 Antenna
The in-built antenna is made as a pattern on a fl exible printed circuit foil supported by a plastic
carrier containing the loudspeaker and attached to PCB. This HDA type antenna is fed via 2
contacts springs, one grounded and one connected to RF signal.
The antenna signal is also accessible through the external antenna connector located at the upper
part on back of the phone.
FUNCTION OVERVIEW Description
2.5 BLUETOOTH
The Bluetooth implementation is compliant with Bluetooth specifi cation 2.0 + EDR
2.5.1
The Bluetooth
MHz. The same band is used for both transmission and reception. This gives 79 frequency
channels.
2.5.2
The Bluetooth
One synthesizer is used for both RX and TX. To separate the receiver from the transmitter an
integrated antenna switch is used.
2.5.3
The fi rst stage of the receiver is an external antenna fi lter, which suppresses unwanted
frequencies. The receiver is of a "near-zero" IF receiver architecture. The local oscillator is
generated by a frequency synthesizer, which allows the receiver to be set at frequencies in
intervals of 1 MHz. The synthesizer is controlled from the logic part.
The received signal is sampled in the logic for later signal processing.
2.5.4
The synthesizer generates the TX frequency which modulated by the BT baseband block. It
is then amplifi ed. The BT system is a class 1 device with maximum of +4 dBm output power
(minimum setting is about -50 dBm).
2.5.5
The purpose of the logic part is to control and monitor the transmission and reception functions of
the Bluetooth
parts of the radio. Its functions, with reference to the radio, include selection of radio channel and
control of radio timing. It also generates the data to be sent over the link after burst building and
channel coding. The logic/audio part also demodulates the received base-band signal including
channel decoding.
Its functions, with reference to the audio parts, include a PCM interface.
2.5.6
The antenna is in-built and located in the bottom part of the phone. The antenna is in contact with
the PCB by means of two metal springs.
TM
RF part
transceiver has frequency channels with 1 MHz separation from 2402 to 2480
TM
Frequency generation
transceiver uses the 13 MHz system clock as reference clock to the synthesizer.
TM
Receiver
Transmitter
Logic/Audio part
TM transceiver in the mobile phone. The logic therefore has links with all the relevant
Antenna
SEMC Electrical Repair Manual
K800 - K810
1202-3085 rev. 2 5 (121)