BCM3137 OVERVIEW
The Broadcom BCM3137 QAMLink®Universal
QPSK/16 QAM Burst Receiver is a complete single-chip cable
network receiver, that accepts QPSK and 16 QAM upstream
burst data in a frequency-agile, time-division multiple access
(TDMA) scheme. An analog front-end (AFE), a QAM
demodulator and an FEC decoder are integrated on this single
chip. The AFE performs coarse gain setting and A-to-D
con version on either an IF input or baseband I/Q inputs. A digital
down-mixer translates the input spectral center to true DC.
The I and Q samples pass through dual decimators and square-
root raised cosine filters with an excess bandwidth α= 0.25.
Fast burst detection and acquisition are performed on the
preamble with programmable length and pattern. The chip
incorporates unique word (UW) detection in the preamble
process to delineate the packet and resolve phase ambiguity.
Carrier phase offset is removed by a derotator. An adaptive
equalizer characterizes the RF channel response and removes
inter-symbol interference (ISI) caused by micro-reflections.
The FEC decoder consists of a programmable derandomizer and
a programmable RS decoder. FIFO buffers provide input/output
data rate de-coupling for the FEC decoder.
The BCM3137 delivers the recovered data stream and accepts
receiver control inputs through a receive interface linked to an
MCNS MAC chip. The BCM3137 prepends ranging and data
information to each received code word and packet for
processing by the BCM3210B. An ATM UTOPIA-like receive
interface is also supported in a bit-serial style. The BCM3137
can be configured through either an SPI or I2C-compatible
serial interface.
The BCM3137 represents a highly-integrated, mixed-signal
solution that significantly increases the channel density per line
card for CMTS implementations. When combined with the
BCM3033 QAMLink Universal Modulator and the BCM3210B
QAMLink CMTS Media Access Controller, these chips are an
ideal solution for cable headends. A complete CMTS reference
design (BCM93210B), which integrates these three chips, is
available from Broadcom, providing a complete development
platform for a multi-channel, DOCSIS/EuroDOCSIS-compliant
Cable Modem Termination System.
Phone: 949-450-8700
FAX: 949-450-8710
Email: info@broadcom.com
Web: www.broadcom.com
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Broadcom Corporation and/or its subsidiaries in the United States and certain other countries.
All other trademarks are the property of their respective owners.
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© 2002 by BROADCOM CORPORATION. All rights reser ved.
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