User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Document history
- Introduction
- Product concept
- GSM application interface
- GSM/GPRS operating modes
- Power supply
- Power up / down scenarios
- Automatic GPRS Multislot Class change
- Charging control of the GSM part
- Power saving
- Summary of state transitions (except SLEEP mode)
- RTC backup for GSM part of XT55/56
- Serial interfaces of the XT55/56 GSM part
- Audio interfaces
- SIM interface
- Control signals
- GPS application interface
- GSM and GPS antenna interfaces
- Electrical, reliability and radio characteristics
- Mechanics
- Reference approval
- Example applications
- List of parts and accessories
XT55/56 Hardware Interface Description
Confidential / Released
s
XT55/56_hd_v02.06a Page 102 of 125 17.12.2004
6.5 Electrical characteristics of the voiceband part
6.5.1 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 analog 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 analog 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 inCalibrate, outCalibrate and sideTone accept also values from 32768
to 65535. These values are internally truncated to 32767.