User Guide

PAMS
Technical Documentation
RAE–2
Baseband
Page 2– 6
Original 02/99
The baseband is running from a 2.8V power rail, which is supplied by the
power controlling ASIC. In the CCONT ASIC there are 6 individually con-
trolled regulator outputs for RF–section and two outputs for the base-
band. In addition there is one +5V power supply output (V5V) for flash
programming voltage and for other purposes where a higher voltage is
needed. The CCONT contains also a SIM interface, which supports both
3V and 5V SIM–cards.
Figure 2. BS8 Module
BaseBand Side RF Side
The interface between the baseband and the RF section is handled by
the specific ASIC COBBA. The COBBA provides:
– A/D and D/A conversion of the in–phase and quadrature receive and
transmit signal paths
– A/D and D/A conversions of received and transmitted audio signals to
and from the UI section.
The COBBA supplies the analog TXC and AFC signals to the RF section
according to the MAD DSP digital control and converts the analog AGC
into digital signal for the DSP. The data transmission between the COB-
BA and the MAD is implemented using a parallel connection for high
speed signalling and a serial connection for PCM coded audio signals.
Digital speech processing is handled by the MAD asic.
The COBBA is a dual voltage circuit, the digital parts are running from the
baseband supply VBB and the analog parts are running from the analog
supply VCOBBA.