AR-11627 Datasheet, PDF (4/24 Pages) Conexant Systems, Inc – AccessRunner ADSL Modem Device Set for PCI Applications

AccessRunner
Digital Interface (DI)
The DI Transmit Block performs the following
functions: transmit data multiplexing and buffering,
fast and interleave data stream framing, transmit
data synchronization control, eoc/aoc insertion, CRC
encoding, scrambling, FEC encoding, and data
interleaving.
The DI Receive Block performs the following
functions: data de-interleaving, FEC decoding,
descrambling, CRC check, receive data
synchronization and receive clock generation,
demultiplexing and buffering of receive data and
receive eoc/aoc.
QAM Encoder/Decoder
The QAM Encoder/Decoder performs the following
functions: constellation encoding, clock recovery,
receive gain compensation, frequency domain
equalization (FEQ), slicing, and constellation
decoding. The block also performs other functions
like frequency domain signal processing, signal
power, error power averaging and computations
related to frequency domain training.
FFT
The FFT performs IFFT for modulation of the
transmit symbol, and FFT for demodulation of the
receive symbol.
Controller-less ADSL Modem Device Set for PCI Applications
Analog Front End (AFE) Interface
The AFE Interface performs the following functions:
transmit signal filtering, time domain equalization,
and time domain signal power averaging, and echo
cancellation (EC).
Microcontroller Interface
The microcontroller interface enables the host
computer via the PCI controller to set parameters to
control DSP sequencing and to read/write
coefficients or data.
20441 Line Driver
The 20441 line driver is designed for use in full-rate
and G.lite (G.992.2) ADSL modems. It is optimized
for ideal ADSL performance providing low noise,
high bandwidth, and superior linearity. The 20441
line driver transmits a DMT modulated signal in the
25 – 132 kHz band. It operates from a single 5V
±TBD% supply, refer to
Figure 3.
The driver is optimized for ADSL performance: it has
a very low noise figure, high bandwidth and good
linearity.
INP_DRV
INM_DRV
RBIAS
248.4
+
+
400
+
248.4
Current Control
Block
Line Driver
( ₍₂₀₄)₄₁₎
OUTP_DRV
OUTM_DRV
Figure 3. AccessRunner 20441 Line Driver
DSL015_003
4
Conexant
Doc. No. 100394B
Proprietary Information
October 19, 1999