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Fastrack Supreme User Guide
Technical Characteristics
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Page: 65 / 77
8.2.3
Audio Interface
The audio interface is available through the Sub HD 15-pin connector.
Table 19: Audio parameters caracteristics
Audio parameters
Min
Typ
Max
Unit
Comments
Microphone input current @2 V/2 k
Ω
0.5 mA
Absolute microphone input voltage
100
mVpp
AC voltage
Speaker output current 150
Ω
//1 nF
16 mA
Absolute speaker impedance
32
50
Ω
Impedance of the speaker amplifier output in
differential mode
1
Ω
+/-10 %
Table 20: Microphone inputs internal audio filter characteristics
Frequency
Gain
0-150 Hz
< -22 dB
150-180 Hz
< -11 dB
180-200 Hz
< -3 dB
200-3700 Hz
0 dB
>4000 Hz
< -60 dB
Table 21: Recommended characteristics for the microphone:
Feature
Value
Type
Electret 2 V / 0.5 mA
Impedance
Z = 2 k
Ω
Sensitivity
-40 dB to –50 dB
SNR
> 50 dB
Frequency response
compatible with the GSM specifications