V1.0
10
Hardware Description
The handset consists of the following major integrated circuits:
1)
E-GOLD (PMB 2850)
This IC is a combination of microprocessor and signal processor.
The microprocessor part of this component is responsible for controlling the keyboard, SIM-
Card, Flash and RAM. Furthermore it controls the power up/power down of the RF module
and sets the amplification of the PA.
The signal processor part of PMB 2800 is responsible for processing the Rx I/Q signals
(filtering, equalizing, speech and channel decoding).
Furthermore it does the speech and channel encoding and the GSMK modulation of the Tx
I/Q signals.
The coprocessor PMB 2805 is used to realize advanced features regarding coding of the
speech signal. These are:
•
Halfrate-Encoding
•
Halfrate-Decoding
•
Enhanced Fullrate Encoding
•
Enhanced Fullrate Decoding
•
Voice Activity Detection
•
Comfort Noise
3)
GAIM (PMB 2906)
The GAIM (GAIM =
G
SM
A
nalog
I
nterfacing
M
odule) provides the interface between the
analogue signals (I/Q, voiceband, PA-control, charging control signals) and its digital
representation.
4)
Transceiver Circuit (Bright II HD155124F)
This circuit provides the following main functionalities:
•
Low Noise Amplifier (LNA) with a fixed amplification of +20dB to amplify the input RF
signal.
•
Mixer to mix down the RF signal to the Intermediate Frequency (IF)
•
Programmable IF amplifier with a dynamic range of 60dB ( -10dB ~+50dB in steps of
2dB).
•
Mixer to mix down the IF signal to the baseband, generating and inphase (I) and a
quadrature (Q) signal.
•
Offset compensation for the I/Q signals.
This circuit provides the IF synthesizer, the I/Q modulator, prescalers to regulate the RF
synthesizer and a buffer stage to feed the PA.
The antenna switch is mechanical, located in the connector for the external antenna.
Power Supply Concept
