U4091BM-N Datasheet, PDF (28/38 Pages) ATMEL Corporation – PROGRAMMABLE TELEPHONE AUDIO PROCESSOR

2. P (the pole position of the low-pass)
The P adjustment has 31 steps. P(0) means the lowpass determined by the
external application (RST, CST). The internally processed low-pass frequency is
fixed by equation:
f(P) = -₂----_×------_π-----_×------_C---¹-_S----_T-----_×------_R----_S----_T-- × 1.122^P
3. SL (sidetone slope; the pole frequency of the high-pass)
The SL has 3 steps. SL(0) is a lower frequency of the high-pass. SL(3) is a
higher frequency of the high-pass. With SL, can be influenced the suppression at
high frequencies.
Figure 21. Audio Frequency Signal Management U4091BM-N
-10dB
-3dB ... -10dB and 7dB (NWT)
ST
7dB → 0dB and
20dB (NWT)
VL
Line
Sidetone
balancing
1dB steps
Offset
cancel
Handset
micro-
phone
Intercom
micro-
phone
MIC1
0dB
MIC2
MIC3
0dB
Answering
machine AMPB
DTMF
generator
Filter
30dB→ 12dB
→
7dB→ -48dB
6dB steps
1dB steps
DTMF
< -24dBm/
-22dBm >
Offset
cancel
0dB
Offset
cancel
32dB→ -23dB
LRX
RXLS
1.5dB steps
26dB→ -3dB and
-10dB (DTMF)
DTMF
EPO
Switching
matrix
1dB steps
9dB → 2dB
MIC
LTX
1dB steps
AMPB AMREC
0dB
SAO1
6dB
Loud-
speaker
SAO2
RECO1
RECO2
Earpiece
DTMF
< -34dBm/
-32dBm >
VL
8dB
MOD
Line
AMREC _Answering
machine
0dB
AGCO
AGCI
0dB
AGC
14578
28 U4091BM-N
4666B–CORD–08/04