Telit GE863-QUAD / GE863-PY
Hardware User guide
1vv0300715, Rev. ISSUE#0, - 21/02/06
Reproduction forbidden without Telit Communication written authorization – All Right reserved – Right of modification reserved
page 40 of 71
7 Speaker
7.1 Speaker lines characteristics and requirements
The Telit GE863-QUAD/PY provides two audio paths for both the microphone and the earpiece:
the internal and the external audio paths. Only one of the two paths can be active at a time and it
is selectable by hardware line AXE or by AT command. The audio characteristics of the two
paths are slightly different and this should be kept in mind when designing your application. The
internal audio path should be used for handset function, while the external audio path is suited
for hands free function (car kit).
Both speaker outputs from the Telit GE863-QUAD/PY are bridged type and the OEM circuitry
shall be designed bridged to reduce the common mode noise typically generated on the ground
plane and to get the maximum power output from the device; however for particular OEM
application needs also a single ended circuitry can be designed.
The GE863-QUAD/PY speaker output lines characteristics are:
internal speaker path ( , EAR_MT- )
•
line
coupling:
DC
•
line type:
bridged
•
speaker impedance (operating conditions):
≥
16
Ω
± 5% @ 1kHz
•
minimum
load
impedance:
15
Ω
•
signal bandwidth:
150 - 8000 Hz @ -3 dB
•
maximum
differential
output:
850
mV
rms
•
rated
output
power:
10
mW
•
maximum
power
output: 30
mW
•
volume level steps (SW):
- 2 dB
•
number
of
volume
steps(SW):
10
