AM79Q031 ETC1 [List of Unclassifed Manufacturers], AM79Q031 Datasheet - Page 32

• Manufacturer Part Number: AM79Q031
• Description: Quad Subscriber Line Audio-Processing Circuit (QSLAC) Devices
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

7. Transmit time slots and receive time slots are set to
8. DXA port is selected for all channels.
9. DRA port is selected for all channels.
10. The master clock frequency selected is 8.192 MHz
11. All four channels are selected in the Channel
12. Any pending interrupts are cleared, all interrupts
13. The supervision debounce time is set to 8 ms.
14. The previously programmed B, Z, X, R, GX, and
15. The chopper clock frequency is set to 256 kHz but
32
V
Full
Digital
Loop
back
(FDL)
V
IN
OUT
0, 1, 2, and 3 for channels 1, 2, 3, and 4,
respectively. The clock slots are set to 0, with
transmit on the negative edge.
and is programmed to come from PCLK.
Enable register.
are masked, and the Interrupt Output state is set to
open drain.
GR filters are unchanged.
the chopper clock is turned off.
AISN
+
VREF
*
AX
*
AR
*
ADC
DAC
*
polator
programmable blocks
mator
Deci-
Inter-
Figure 12. QSLAC Device Block Diagram
Z
+
Am79Q02/021/031 Data Sheet
*
High Pass Filter (HPF)
mator
Deci-
polator
Inter-
B
+
16. The E1 Multiplex state is turned off and the polarity
17. No signalling on the PCM highway.
SIGNAL PROCESSING
Overview of Digital Filters
Several of the blocks in the signal processing section
are user programmable. These allow the user to
optimize the performance of the QSLAC device for the
system. Figure 12 shows the QSLAC device signal
processing and indicates the programmable blocks.
The advantages of digital filters are:












*
GR
GX
*
*
High reliability
No drift with time or temperature
Unit-to-unit repeatability
Superior transmission performance
Flexibility
Maximum possible bandwidth for V.34 modems
is set for high going pulses.
Lower Receive
R
X
*
*
Gain (RG)
& HPF
LPF
LPF
Cutoff Receive
Path (CRP)
0
pressor
pander
Com-
Loopback
Ex-
(TLB)
TSA
1 kHz Tone
(TON)
TSA
TSA
Cutoff
Transmit
Path
(CTP)
21108-027
Digital
RX
Digital
TX