OVERVIEW

®

Phone: 949-450-8700

Fax: 949-450-8710

E-mail: info@broadcom.com

Web: www.broadcom.com

BROADCOM CORPORATION

16215 Alton Parkway, P.O. Box 57013

Irvine, California 92619-7013

© 2006 by BROADCOM CORPORATION. All rights reserved.

3520-PB05-R

10/23/06

are among the trademarks of Broadcom Corporation and/or its affiliates in the United States, certain other

countries and/or the EU. Any other trademarks or trade names mentioned are the property of their

respective owners.

BCM3520 Block Diagram

The BCM3520 is a ATSC/NTSC/QAM Digital Cable Ready DTV

receiver that contains a digital receiver that is compatible with both

North American digital cable television and digital terrestrial broadcast

television standards. This receiver is capable of receiving all standard-

definition and high-definition digital formats (SDTV/HDTV). It also

contains an IF demodulator compatible with the NTSC video standard.

The output of the IF demodulator can be directed to an external BTSC or

Zweiton M decoder, or can be sent to an on-chip audio decoder. The on-

chip audio decoder is fully compliant with the BTSC audio standard. An

out-of-band QPSK receiver is also contained to meet the needs of the

CableCard specification.

The BCM3520’s digital receiver and NTSC demodulator accepts an

analog signal centered at the standard television IF frequencies, and

amplifies and digitizes this signal with an integrated programmable gain

amplifier and 12-bit A/D converter. The output of the A/D is sent to the

receiver and demodulator. The digital receiver consists of a QAM

demodulator and a VSB demodulator. Each demodulator contains

adaptive filters that remove multi-path propagation effects, NTSC co-

channel interference, and RFI interference. The output of the VSB

demodulator goes to an ATSC A/53 coding forward error corrector

(FEC), with integrated trellis and Reed-Solomon decoder. The output of

the QAM demodulator goes to an ITU-T J.83 Annex A/B/C coding FEC.

The output of either QAM or VSB FEC is delivered in either parallel or

serial MPEG-2 transport format. The NTSC demodulator filters and

demodulates the analog NTSC and FM audio signals and delivers a

composite output via an on-chip 10-bit DAC. An IF modulated audio

output is also provided via a second on-chip 10-bit DAC. An on-chip

BTSC decoder handles the decoding of the base-band multiplexed audio

from the IF demod, providing an stereo left/right, mono, or SAP output

via a pair of high precision HiFiDACs.

All gain, clock, and carrier, acquisition, and tracking loops are integrated

on-chip as are the necessary phase-locked loops, referenced to a single

external crystal.

Chip configuration, channel acquisition, and performance monitoring

functions are conducted by the on-chip acquisition processor using

Broadcom-provided software.

EIA/CEA-909

Interface

JTAG

Interface

HiFi DAC

Master

PLL

Output

Interface

BTSC

Decoder

10-Bit D/A

HAB

10-Bit D/A

BSC Master

Interface

OOB AFE

PGA

6-Bit A/D

AGC Control

VCO

In-Band AFE

PGA

12-Bit A/D

AGC Control

GPIO/GPO

Interface

16-1024 QAM

Advanced Receiver

ITU-T J.83

Annexes A/B/C FEC

ATSC FEC

ATSC 8/16 VSB

Advanced Receiver

BSC/SPI Slave

Interface

Acquisition

Processor

BSC/SPI Host Interface

In-Band Tuner

Interrupt

MPEG Transport

Composite NTSC

IF Audio

L/R Audio or Multiplexed

Baseband Audio

OOB Transport for

CableCard/POD

In-Band AGC

In-Band AFT

OOB Tuner

OOB AGC

OOB VCO

Internal Bus

To All Blocks

Tuner/Peripheral

Control

GPIO

GPO

Antenna

Control

JTAG

Controller

BCM3520

NTSC IF

DEMODULATOR

DVS-167 FEC

DVS-178 FEC

OOB Output

Interface

OOB QPSK

Receiver