
Tx Characteristics
Symbol
Gtx
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
Transmit Gain
_MIKGAIN=7FFF,_TXGAIN=7FFF, AGC disabled
V
MIC2
= -21dBV
V
MIC2
= -9dBV
2k
between MIC2 and GND
V
MIC2
= -21dBV
_MIKGAIN=7FFF,_TXGAIN=7FFF, AGC disabled
see Figure 3, V
MIC2
= -9dBV
_MIKGAIN=7FFF,_TXGAIN=7FFF, AGC disabled
see Figure 3, V
MIC2
= -9dBV
18
8
-73
60
2.5
dB
dB
Ntx
Mmic
VLpeak
Transmit noise
Microphone mute
Transmit softclipping
level on TxA1-TxA2
Transmit distortion
dBmp
dB
Vpp
Dtx
2
%
Rx Characteristics
Symbol
Grx
Nrx
Mrx
Dtx
Parameter
Test Conditions
Min.
Typ.
6
-79
60
Max.
Unit
dB
dBmp
dB
%
Receive Gain
Receive noise
Mute
Receive distortion
(SPK2 output)
_SPKGAIN=7FFF,AGC disabled, V
RXA
= -16 dBV
V
RXA
= dBV
_SPKGAIN=7FFF,AGC Disabled,V
RXA
= -16dBV
2
AGC
The line current information is coming from the
D.A.A.on DP_RINGpin(frequencycodedinforma-
tion using by example a TS555 general purpose
timer).The AGChas a6dBdepth. Theattenuation
table can be loaded to comply with each country
regulation.The default table has the followingval-
ues. The value of the AGC gain is applied to both
Tx and Rx path (see Table1).
The address of the table is given in the register
@_TABLE.
The table length is 53. The AGC is enabled using
CONF or MODC command (see paragraph ”VII -
COMMAND SETDESCRIPTION”.
Oncethe AGCisrunning,it ispossibletofreezethe
AGC gainwith theregister AGC_FRZ.
Softclipping
The softclippingintroducesa 12dBgain and has a
18dBdepth.
The softclipping value is half digital range
(4000 Hex) (see Figure5).
V - FUNCTIONALDESCRIPTION
(continued)
10
4
10
3
10
2
10
V
MICX
(mV
RMS
)
10
3
0
2
4
6
8
10
12
(mV
RMS
)
D (%)
VTxA1-TxA2 (V
RMS
)
Distortion
Tx Softclipping and Distortion
10
2
7
Figure 5 :
SoftclippingStatic Gain
Table1 :
AGCGainversus Period Information
Period (ms)
Table Index
Gain (dB)
<9
<13
0
10
13
0.7
10.8
14
1.5
11.6
15
2.2
14.5
16
3
13.3
17
3.4
14.1
18
4
15.5
19
4.5
16.6
20
4.8
17.5
21
5.1
18.3
22
5.4
19.1
23
5.6
20
24
5.8
>20
>24
6
ST75C530 - ST75C540
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