BCM312 5
PRODUCT
®
Brief
O F
B E N E F I T S
BCM312 5
QAMLink
®
UNIVERSAL TRANSMISSION SOLUTION
B C M 3 1 2 5
F E AT U R E S
S U M M A R Y
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Integrated QAMLink
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in-band receiver
10-bit A/D converter with input AGC amplifier
Variable symbol rate 256-QAM receiver
Digital demodulator, Nyquist filters, tracking loops,
and 32-tap adaptive decision feedback equalizer
ITU-T J.83 Annex A/B/C compatible FEC decoder
®
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Universal set-top and cable modem front-end
supports the ITU-T J.83 Annex A/B/C standards, as
well as OpenCable™, DOCSIS/EuroDOCSIS, and
DVB/DAVIC
supporting physical layer requirements including
out-of-band
downstream channels (in-band and out-of-band) and
the upstream channel
and upstream blocks reduces board complexity and
system costs
count
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Connects directly to Broadcom digital TV ICs
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Represents a complete solution for dual
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Integrated QPSK out-of-band receiver
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Baseband interface to dual 6-bit A/D converters or IF
interface to signal A/D converter
Variable symbol rate QPSK receiver
Digital demodulator, Nyquist filters, tracking loops,
and 4-tap adaptive decision feedback equalizer
DigiCipher
®
II/DVB/DAVIC FEC decoder
MPEG transport output interface/DAVIC MAC
output interface
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Integrated analog front end for the dual downstream
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Serial control interface results in reduced overall pin
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Out-of-band QPSK receiver provides flexibility for
IF or baseband inputs
VCXOs
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Integrated upstream transmitter
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Programmable Starvue
II/DOCSIS™/EuroDOCSIS™/DVB/ DAVIC FEC
encoder
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Pre-equalization filter
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Up to 6 MBaud variable rate QPSK/16-QAM modulator
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10-bit D/A converter with output power control
interfaces
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Single, low-cost crystal solution eliminates costly
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Includes direct interface to the OpenCable point-of-
deployment (POD) module
channels
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Control unit
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Single device supports both 6-MHz and 8-MHz
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Allows direct connection to Broadcom ICs to support
additional data and video channels for
DOCSIS/EuroDOCSIS/DAVIC systems and PVR set-
top boxes
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BSC/SPI compatible interface for configuration and
device control
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RF tuner control
160-pin PQFP package
Set-Top Box Block Diagram
In-Band Channel
BCM3125
QAMLink
®
Universal
Transmission
Solution
Audio
BCM7020/BCM7030
High Definition Video /
Graphics Subsystem
Video
Tuner
Out-of-Band Channel
Upstream Channel
CPU
I/O
Memory
BOARDCOM [ Broadcom Corporation. ]
