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AC75 Hardware Interface Description
Strictly confidential / Preliminary
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AC75_HD_V00.202
Page 96 of 120
27.04.2006
5.7
Electrical Characteristics of the Voiceband Part
5.7.1 Setting Audio Parameters by AT Commands
The audio modes 2 to 6 can be adjusted according to the parameters listed below. Each
audio mode is assigned a separate set of parameters.
Table 30: Audio parameters adjustable by AT command
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 (inCalibrate/
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 summation of
sidetone and DAC
Present for each volume step[n]
0...32767 -
∞
...+6dB
20 * log (2 *
outCalibrate[n]/
32768)
sideTone
Digital attenuation of sidetone
Is corrected internally by outBbcGain to
obtain a constant sidetone independent
of output volume
0...32767 -
∞
...0dB
20 * log (sideTone/
32768)
Note: The parameters outCalibrate and sideTone accept also values from 32768 to 65535.
These values are internally truncated to 32767.