MC55i Terminal Hardware Interface Description
4.5 Electrical Characteristics of the Voiceband Part
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4.5
Electrical Characteristics of the Voiceband Part
The electrical characteristics of the voiceband part depend on the current audio mode selected
by the AT command AT^SNFS. See
: Audio modes.
The audio modes 4 and 5 can be adjusted by parameters. Each audio mode is assigned a sep-
arate parameter set.
Note:
The parameters inCalibrate, outCalibrate and sideTone accept also values from 32768
to 65535. These values are internally truncated to 32767.
Table 20:
Audio parameters adjustable by AT commands
Parameter
Influence to
Range
Gain range
Calculation
inBbcGain
MICP/MICN analogue amplifier
gain of baseband controller before
ADC
0...7
0...42dB
6dB steps
inCalibrate
digital attenuation of input signal
after ADC
0...32767
-
...0dB
20 * log (inCali-
brate/
32768)
outBbcGain
EPP/EPN analogue output gain of
baseband controller after DAC
0...3
0...-18dB
6dB steps
outCalibrate[n]
n = 0...4
digital attenuation of output signal
after speech decoder, before sum-
mation of sidetone and DAC
present for each volume step[n]
0...32767
-
...+6dB
20 * log (2 * out-
Calibrate[n]/
32768)
sideTone
digital attenuation of sidetone
is corrected internally by outBbc-
Gain to obtain a constant sidetone
independently to output volume
0...32767
-
...0dB
20 * log (sideTone
32768)
