User Guide

PAMS
Technical Documentation
RAE–2
Baseband
Page 2– 7
Original 02/99
The COBBA supports three microphone inputs and two earphone out-
puts. The inputs can be taken from an internal microphone, a headset mi-
crophone or from an external microphone signal source.
The output for the internal earphone is a dual ended type output capable
of driving a dynamic type speaker. Input and output signal source selec-
tion and gain control are performed inside the COBBA according to con-
trol messages from the MAD. Call alerts, keypad tones, DTMF, and other
audio tones are generated and encoded by the MAD and transmitted to
the COBBA for decoding.
EMC shielding (figure below) is implemented on the BB side using a me-
tallized plastic B–cover and conductive gasket between the B–cover and
the PCB. On the RF side the engine is shielded with a conductive frame
which makes a contact to a ground ring of the CMT board and a ground
plane of the PDA board. There is a conductive gasket between the frame
and the PCB for ensuring proper shielding. In addition he RF area has
three metal cans for RF shielding. Heat generated by the circuitry is con-
ducted out mainly via the PCB ground planes.
Bottom connector
Microphone
4 srews for fastening
B–cover to frame
Metallized B–cover
BS8 module
Metal
gasket
Conductive frame +gasket
Metal cans