BASEBAND OVERVIEW
Issue 1
Section 6
MCUK991001G8
Revision 0
– 24 –
Technical Guide
When using the internal Handsfree feature, the receive audio frequency response must fit within the mask shown below.
Figure 6.8: Handsfree GSM Transmit Audio frequency response mask
6.2.10 Desktop Hands Free Mode (GD50 only)
In handheld mode, the speaker is driven by the ear-piece amplifier inside VEGA U504.
GD50 can operate in desktop (internal) hands free mode. This is achieved by disabling the ear-piece amplifier and driving the
speaker from the auxiliary speaker output in VEGA via external power amplifier U601. The power amplifier is enabled via the
nINT_HF signal from SIM Interface/Port Expander U501.
Figure 6.9: Speaker connection for GD50 Handheld/Desktop Hands Free operation
dB
0
-10
-5
-15
100
1000
10000
Frequency (Hz)
10072-1
10169-1
VEGA
U504
PORT
EXPANDER
U501
POWER
AMPLIFIER
U601