Downstream QAM receiver for international
applications
Integrated QAMLink receiver with Forward Error
Correction (FEC)
1-7 MBaud variable symbol rate receiver
Supports variable channelization
Supports 4, 16, 32, 64, 128 and 256-QAM
Digital demodulator, Nyquist filters, tracking loops,
and 20-tap adaptive decision feedback equalizer
Digital derotator for wideband carrier phase tracking
DVB/DAVIC-compliant FEC decoder
Reed-Solomon (N,K) = 204,188: t=8
Convolutional detinterleaver, I=1-12 with internal
RAM, I=204 with external RAM
I
2
C or SPI-compatible microcontroller interface
Integrated 10-bit analog-to-digital converter
On-chip generation of all clock and control signals
JTAG test interface
100-pin PQFP Package
B C M 3 1 1 8 B F E A T U R E S
S U M M A R Y O F B E N E F I T S
Fully-integrated solution enables less-complex,
low-cost cable modems and cable-TV set-top boxes
Significantly increases channel capacity
Variable data rates enable systems to adapt to
channels encoded at different data rates
Integrated A/D converter reduces system
manufacturing costs and complexity
A universal chip solution that supports DVB, DAVIC,
ITU-T J.83/Annex A and Annex C, IEEE 802.14-based
systems
Digital adaptive equalizers ensure robust performance
in the presence of multipath reflections
B C M 3 1 1 8 B Q A M L I N K
D V B / D AV I C R E C E I V E R
PRODUCT
Brief
B C M 3 1 1 8 B
CPU
BCM3118B
Video 2
Out-of-Band
DOCSIS
Video 1
Video 2
PCI
Video 1
Audio Out
Video Out
BCM3250
Advanced
Single-Chip
Set-top Box
Front End
BCM7030
High Definition
Video/Graphics
Subsystem
Interactive Set-top Box with DOCSIS and Watch and Record Dual Video Channels
The BCM3118B QAMLink DVB/DAVIC Receiver with FEC is
an integrated digital transmission solution for cable modems,
cable-TV set-top boxes and digital microwave radios. Its
bandwidth-efficient feature set expands the existing potential
bandwidth of a standard analog network and provides operators
with reliable, error-free transmission. Optimized for high-
volume manufacturing, the BCM3118B is a highly integrated
solution that reduces the system-level chip count, the cost, and
the complexity associated with manufacturing RF receivers.
A single-chip solution, the BCM3118B has a 10-bit A/D
converter, a 256-QAM demodulator with square-root raised-
cosine receive filters, an adaptive equalizer with an embedded
phase recovery derotator, acquisition and tracking loops, and a
DVB/DAVIC-compliant Reed-Solomon FEC decoder with
deinterleaver. The demodulator supports QPSK, 16, 32, 64, 128
and 256-QAM formats and adapts to channels encoded at
different data rates up to 56 Mbps. The equalizer in the
BCM3118B achieves transmission performance within 1 dB of
theory over worse-case channels with multipath delays as long as
2.4 microseconds at 5 MBaud or 1.7 microseconds at 7 MBaud
and amplitudes within .5 dB of the desired signals. With this
level of performance, the BCM3118B combats the effects of
channel distortions commonly found in cable-TV systems. The
BCM3118B has an integrated A/D converter, which eliminates
the costs associated with fine tuning of external components
during high-volume production.
The BCM3118B samples the analog IF waveform being
delivered to BCM3118B by the integrated A/D converter. The
signal is then digitally mixed to baseband and filtered by dual
square-root Nyquist filters. Inter-symbol interference is then
removed by the adaptive decision feedback equalizer. A decision
slicer, which supports constellations up to 256-QAM, formats the
equalized data. The data is then fed into a DVB/DAVIC-
compliant synchronization block, deinterleaver, Reed-Solomon
FEC, and derandomizer. The final error-corrected output is
delivered in an MPEG-2 transport format.
The BCM3118B can be used as a stand-alone chip or with
Broadcom's BCM3250 for a complete watch and record solution
with EuroDOCSIS. Compliant with the ITU-T J83/Annex A and
Annex C, DVB/DAVIC and the IEEE802.14 cable transmission
standards for QAM downstream, the BCM3118B is a universal
downstream solution for worldwide coaxial cable applications.
B C M 3 1 1 8 B O V E R V I E W
Phase
Recovery
and
8-tap
FFE
Deinterleaver
RAM
A_IF+/-
LPS_SYNC
JTAG [3:0]
LPS_DATA [7:0]
PS_DATA
A/D
Variable
Rate
Demod
Nyquist
=
= .13-.15
MBus/SPI
Interface
JTAG
10
RF [5:0]
cos
M
n
sin
M
n
Phase
ROM
12-tap
DFE
Q
I
Tuner
Control
LPS_CLK
MICRO [3:0]
RAM_CTRL
PS_ERR
4
4
Nyquist
=
= .13-.15
AGC_CTRL
IF_OSC
GEN_CTL
BAUD_CTRL
Reed-
Solomon
Decoder
(204, 188)
t=8
Acquisition/Tracking Loops
and Clock Generation
For more information please contact us at:
Phone: 949-450-8700, FAX: 949-450-8710
Email: info@broadcom.com
Visit our web site at: www.broadcom.com
2001 BROADCOM CORPORATION
3118B-PB02-R-8.17.01
Broadcom
and the pulse logo
are registered trademarks of Broadcom Corporation.
QAMLink is a trademark of Broadcom Corporation.
BROADCOM CORPORATION
16215 Alton Parkway, P.O. Box 57013
Irvine, California 92619-7013
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