博通BCM4505单片卫星电视接收方案

博通(Broadcom)公司的BCM4505是全集成卫星电视接收器单片解决方案,它集成了CMOS调谐器和支持DVB-S2广播, DVB-S, DIRECTV®,以及8PSK Turbo应用的调谐译码器. BCM4505还支持1-45Msps DCB工作范围,输入频率从215MHz到2150MHz,包括有2个8位ADC,全数字可变速率QPSK/ 8PSK接收器,高档调制LDPC/BCH 与Turbo FEC译码器以及DVB-S兼容的FEC译码器.此外还集成所有需要的RAM,所有的时钟从外接晶振产生.本文介绍了BCM4505的主要特性,主要优势,方框图以及系统方框图案例.

BCM4505: Advanced Modulation Satellite Receiver
The BCM4505 is a fully integrated satellite receiver single-chip solution targeted at multituner advanced modulation satellite receiver systems and ideally suited for new-generation satellite receivers and integrated multifunction Home Media Centers.
The BCM4505 integrates a CMOS tuner and advanced modulation decoder supporting DVB-S2 Broadcast, DVB-S, DIRECTV®, and 8PSK Turbo applications. The highly integrated tuner section is based on existing volume-production Broadcom technologies and a directconversion technology to reduce external components and increase
performance.

The BCM4505 is designed to support the full 1-45 Msps DVB operating range with support for 250 to 2150 MHz input frequencies. It contains two 8-bit A/D converters, all-digital variable-rate QPSK/ 8PSK receivers, an advanced modulation LDPC/BCH and Turbo FEC decoder, and a DVB-S compliant FEC decoder. All required RAM is integrated and all required clocks are generated on-chip from a single reference crystal. The baseband IQ analog waveforms from the tuner section are sampled by the integrated 8-bit A/D converters and resampled by the integrated interpolative digital filter banks.

Optimized soft decisions are then fed into either a DVB-S-compliant FEC decoder, or an advanced-modulation DVB-S2 LDPC/BCH or Turbo decoder. The final error-corrected output is delivered in MPEG-2 transport format. The output clock is generated by an on-chip PLL for low-jitter operation and glueless integration with Broadcoms high
definition audio video subsystems, such as the BCM7401 and the BCM7402.

The communication link sections include an on-chip microcontroller for all system configuration, acquisition, control, monitoring and diagnostics functions, as well as an integrated DiSEqC 2.x controller for 2-way communication with an LNB, and a single FSK transceiver for communication with ODUs that support multiple LNB configurations over a single coax connection.

The BCM94505 reference design is available for easy system design and testing using the BCM4505 advanced modulation receiver chip. Schematics, Gerber files, and evaluation software are available.

BCM4505主要特性:
Dual direct conversion satellite tuners
Direct conversion architecture in standard CMOS process
Supports QPSK and 8PSK demodulation
Input frequency range: 250 to 2150 MHz
Integrated 8-bit A/D converters
Integrated advanced demodulation decoder
DVB-S2 Broadcast, DVB-S, 8PSK Turbo
Data Rates:
DVB-S: 1-45 Msps
DVB-S2: 1-45 Msps
8PSK Turbo: 2-30 Msps
Code Rates: 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4 , 5/6, 7/8, 8/9, 9/10
Integrated DiSEqC 2.x transceivers
On-chip microcontroller for acquisition and tracking
128-pin epLQFP package
BCM4505主要优势:
Highly integrated, cost effective front-end solution for advanced modulation satellite systems in a single package
Ideal for next-generation PVR satellite systems and Home Media Centers, supporting DVB-S2 Broadcast while maintaining backward-compatible support for DVB-S legacy transmissions.
Advanced design architecture requires no external RAM.
MPEG-2 transport output interfaces provide glueless system integration with Broadcom® integrated audio/video decoders.
Integrated microcontroller for receiver operations, including configuration, acquisition, and performance monitoring.
Host interface operates via a high-level API to reduce software development time and to simplify system integration.
Small footprint and low power consumption



图1.BCM4505方框图



图2.BCM4505系统方框图案例