psb21381 Infineon Technologies Corporation, psb21381 Datasheet - Page 157

• Manufacturer Part Number: psb21381
• Description: Siemens Codec With S/t Transceiver
• Manufacturer: Infineon Technologies Corporation

Description of the programmable parameters:
Parameter # of CRAM
LGAX
COMX
AAX
AGX
AGIX
TMLX
TMHX
NOISX
4.4.5
The Automatic Gain Control of the receive direction AGCR (see figure Chapter 85) is
similar to the transmit AGC. One additional parameter (AAR) offers more flexibility since
the AGCR is able to attenuate signals as well. Depending on the parameters AAR and
AGR different behaviours of the AGCR are possible as figure Chapter 86 illustrates. For
example with AGR set to 0dB and AAR set to maximum (-48 dB) the AGCR acts as a
limiter.
The AGCR is working only together with the speakerphone function (GCR.SP=1). The
digital gain stage LGAR is always enabled in speakerphone mode, independent of the
setting of GCR.AGCR.
It is highly recommended to program reasonable amplifications in the digital gain stages.
Otherwise the ASP will run into saturation above the 3.14 dB PCM-value.
Note that the speech detector for the receive direction is supplied with the signal that
comes out of the AGR-block unless XCR.PGCR = ’1’.
Data Sheet
Automatic Gain Control of the Receive Direction (AGCR)
Bytes
1
1
1
1
1
1
1
1
Range
– 12 to 12 dB
0 to – 73 dB
0 to 47 dB
0 to 18 dB
0 to 18 dB
1 to 2700 ms/dB
1 to 340 ms/dB
0 to – 95 dB
147
Comment
Loudness Gain Adjustment
Compare level rel. to max. PCM-value
Attenuation range of Automatic Control
Gain range of Automatic control
Initial AGC gain transmit
Settling time constant for lower levels
Settling time constant for higher levels
Threshold for AGC-reduction
by background noise
PSB 21381/2
PSB 21383/4
2001-03-12
Codec