BT8954 CONEXANT [Conexant Systems, Inc], BT8954 Datasheet - Page 27

• Manufacturer Part Number: BT8954
• Description: VOICE PAIR GAIN FRAMER
• Manufacturer: CONEXANT [Conexant Systems, Inc]

Bt8954
Voice Pair Gain Framer
Figure 3-3. Receiver Block Diagram
3.3.1 2B1Q Decoder
N8954DSC
QCLK
RDAT
BCLK
TDAT
Decoder
2B1Q
State
CNT
Receive Framer
3.3 Receiver
The receiver performs SYNC word detection, overhead extraction, descrambling
of payload data, error performance monitoring, and payload mapping of DSL data
from the received DSL frame into the PCM RFIFO.
receiver block diagram. The receiver consists of the 2B1Q decoder, receive
framer, descrambler, CRC check, and payload demux.
The 2 Binary, 1 Quaternary (2B1Q) decoder provides the capability to connect
directly to the Bt8960/70 DSL transceivers. The 2B1Q decoder samples and
aligns the incoming sign and magnitude data. Refer to
mapping.
Table 3-2. 2B1Q Decoder Alignment
PD_LOOP
0
1
Detector
Sync
First Bit
(Sign)
1
1
0
0
Descrambler
Detector
Conexant
STUFF
CRC
CHK
(Magnitudes)
Second Bit
0
1
1
0
Payload
Demux
RDAT_DESCR
Figure 3-3
Table 3-2
3.0 Circuit Descriptions
RDSL_6ms
Quaternary Symbol
illustrates the
RFIFO
for 2B1Q
(Quat)
PCM
+3
+1
–1
–3
3.3 Receiver
3-5