Private Communication Systems
Mobile Phones
Hardware Description
The handset consists of five major integrated circuits:
1) HiGOLD (PMB 2800)
This IC is a combination of microprocessor and signalprocessor.
The microprocessor is responsible for controlling the keyboard, SIM-Card, EEPROM,
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 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.
3) GAIM (PMB 2905)
The GAIM provides the interface between the analogue signals (I/Q, voiceband, PA-
control) and its digital representation.
4) Receiver Circuit (PMB 2405/07)
This circuit provides the following main functionalities:
a) Low Noise Amplifier (LNA) with a fixed amplification of +20dB to amplify the input
RF signal.
b) Mixer to mix down the RF signal to the Intermediate Frequency (IF)
c) Programmable IF amplifier with a dynamic range of 60dB ( -10dB ... +50dB in
steps of 2dB)
d) Mixer to mix down the IF signal to the baseband, generating and inphase (I) and a
quadrature (Q) signal.
e) Offset compensation for the I/Q signals.
5) Transmitter Circuit PMB 2240/45
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 electrical, controlled by a signal at the bottom connector.
Power Supply Concept
V1.2 Page 11 of 18 PN MP ST
D. Schnoor
4/98
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