ATSC 8-VSB解调器LSI硬件实现
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摘要
ATSC Standard A/53B标准规定,可以用8-VSB(8 Level Vestigial Side Band)调制方式实现在6Mhz带宽内传输19.39Mbps有效数据。论文详细描述了实现该功能的数字前端接收器的实现方法。数字前端接收器可由一块大规模集成电路来实现(8-VSB-LSI),该芯片从功能上可分为8-VSB解调器(Demodulator)和信道译码器(FEC)两部分。
芯片的8-VSB解调器部分提供对接收信号的处理:首先用正交解调器(Quadrature Demodulate)对A/D采样后数字信号进行解调,同时在这个过程中通过自动增益控制器(Auto Gain Controller)调整RF接受器输出合理增益范围的模拟信号。其次进行信号采样时间恢复(Timing Recovery),即把A/D任意频率采样率信号调整到一个固定采样率。再次用导频跟踪(Pilot Tracking),载波恢复(CarrierRecover)把从天线抖动、频道切换或者噪声脉冲激励等情况下造成的短暂的、偶然的信号丢失中情况下快速恢复。最后用判决反馈均衡器(DFE)把解调后的固定采样率信号从可能对应存在的各种噪声环境,例如信号重影(ghosts),脉冲噪声干扰(noise bursts/impulse noise interference),信号衰减(signal fades),峭壁效应(cliffeffect),同频干扰(co-channel interference),邻近频道干扰(adjacent-channelinterference),多径效应(multipath distortion)中可靠的恢复。信道译码器(ForwardError Correction)提供对包含在信号中的数据进行处理,将已经恢复为按照发送时钟/相位采样的信号流正确复原为MPEG所需格式的数据,主要包括帧同步(Field Sync)、网格译码(Trellis Decoder)、解交织(De-interleaver)、里德所罗门译码(Reed-Solomon Decoder)、解扰码(De-Randomizer),和MPEG编码恢复。
The ATSC Digital Television Standard A/53B describes a system designed to transmit high quality video and audio and ancillary data over a single 6 MHz channel. The 8-VSB system can deliver reliably about 19.39Mbps of throughput in a 6 MHz terrestrial broadcasting channel.This discourse describes the design of digital television front receiver detailedly.The digital teevision front receiver can design to a LSI(large scale integration) which include demodulator and channel decoder.
The main function of 8-VSB demodulator is to deal with the received sample data. First,an analog to digital converter that samples a near base band signal' using a free-running rate and a combined demodulator that demodulates the digitized analog television signals.At the same time,the AGC(Auto Gain Controller) will adjust the RF output gain to a rational range.The Quadrature Demodulator block receives the 25.14Mhz sampling signal which comes from the AD and generantes two quadrature digital signal.Next,a interpolator filter receives the 25.14Mhz sampling signal which comes from the Quadrature Demodulator,after interpolation filtering,the sampling rate is down to 21.52Mhz.When the timing recover device gets to steady state,the 21.52Mhz symbol is down sampled to 10.76Mhz symbol,which is the synchronized samples supplied to the latter functional part,such as SRRC filter.The pilot tracking and carrier recover device can fast resume the signal that is losted transitory or unmeant in the environment of antenna dithering,channel swich and noise impulse. Last,The DFE(decision feedback equalizer) is tO deal with the intersymbol interference(ISI) caused by the wireless channel multipath distortion,symbol ghosts, noise bursts/impulse noise interference,signal fades,cliff effect,co-channel interference,adjacent-channel interference.
The channel decoder(Forward Error Correction) deal with the digital recovery symbol and output the data and control signal according the MEPG spec.It includes the Field Sync、Trellis Decoder、De-interleaver、Reed-Solomon Decoder、De-Randomizer and MPEG recovery.
芯片的8-VSB解调器部分提供对接收信号的处理:首先用正交解调器(Quadrature Demodulate)对A/D采样后数字信号进行解调,同时在这个过程中通过自动增益控制器(Auto Gain Controller)调整RF接受器输出合理增益范围的模拟信号。其次进行信号采样时间恢复(Timing Recovery),即把A/D任意频率采样率信号调整到一个固定采样率。再次用导频跟踪(Pilot Tracking),载波恢复(CarrierRecover)把从天线抖动、频道切换或者噪声脉冲激励等情况下造成的短暂的、偶然的信号丢失中情况下快速恢复。最后用判决反馈均衡器(DFE)把解调后的固定采样率信号从可能对应存在的各种噪声环境,例如信号重影(ghosts),脉冲噪声干扰(noise bursts/impulse noise interference),信号衰减(signal fades),峭壁效应(cliffeffect),同频干扰(co-channel interference),邻近频道干扰(adjacent-channelinterference),多径效应(multipath distortion)中可靠的恢复。信道译码器(ForwardError Correction)提供对包含在信号中的数据进行处理,将已经恢复为按照发送时钟/相位采样的信号流正确复原为MPEG所需格式的数据,主要包括帧同步(Field Sync)、网格译码(Trellis Decoder)、解交织(De-interleaver)、里德所罗门译码(Reed-Solomon Decoder)、解扰码(De-Randomizer),和MPEG编码恢复。
The ATSC Digital Television Standard A/53B describes a system designed to transmit high quality video and audio and ancillary data over a single 6 MHz channel. The 8-VSB system can deliver reliably about 19.39Mbps of throughput in a 6 MHz terrestrial broadcasting channel.This discourse describes the design of digital television front receiver detailedly.The digital teevision front receiver can design to a LSI(large scale integration) which include demodulator and channel decoder.
The main function of 8-VSB demodulator is to deal with the received sample data. First,an analog to digital converter that samples a near base band signal' using a free-running rate and a combined demodulator that demodulates the digitized analog television signals.At the same time,the AGC(Auto Gain Controller) will adjust the RF output gain to a rational range.The Quadrature Demodulator block receives the 25.14Mhz sampling signal which comes from the AD and generantes two quadrature digital signal.Next,a interpolator filter receives the 25.14Mhz sampling signal which comes from the Quadrature Demodulator,after interpolation filtering,the sampling rate is down to 21.52Mhz.When the timing recover device gets to steady state,the 21.52Mhz symbol is down sampled to 10.76Mhz symbol,which is the synchronized samples supplied to the latter functional part,such as SRRC filter.The pilot tracking and carrier recover device can fast resume the signal that is losted transitory or unmeant in the environment of antenna dithering,channel swich and noise impulse. Last,The DFE(decision feedback equalizer) is tO deal with the intersymbol interference(ISI) caused by the wireless channel multipath distortion,symbol ghosts, noise bursts/impulse noise interference,signal fades,cliff effect,co-channel interference,adjacent-channel interference.
The channel decoder(Forward Error Correction) deal with the digital recovery symbol and output the data and control signal according the MEPG spec.It includes the Field Sync、Trellis Decoder、De-interleaver、Reed-Solomon Decoder、De-Randomizer and MPEG recovery.
引文
1.ATSC Standard A53/B(1995),Digital Television Standard.
2.ATSC Standard A/52(1995),Digital Audio Compression(AC-3).
3.ATSC Document A/54(1995),Guide to the Use of the ATSC Digital Television Standard.
4.ISO/IEC IS 13818-1,International Standard(1994),MPEG-2 Systems.
5.ISO/IEC IS 13818-2,International Standard(1994),MPEG-2 Video.
6.Bhasker J.,A Verilgo HDL Primer(Second Edition),2001.
7.Bhasker J.,Verilgo HDL Synthesis:A Practical Primer,Star Galaxy Publishing,PA,1998,ISBN 0-9650391-5-3.
8.IEEE Standard Hardware Description Language Based on the Verilog Hardware Description Language,IEEE Std 1364-1995,IEEE,1995.
9.Proakis,J.G,数字通信.英文版(第四版),电子工业出版社,2004
10.樊昌信,曹丽娜,通信原理(第6版),国防工业出版社,2006
11.王新梅,肖国镇,纠错码:原理与方法(修订版)——21世纪高等学校通信类系列教材,西安电子科技大学出版社,1991
12.王伟,Verilog HDL程序设计与应用,人民邮电出版社,2005
13.余兆明,余智,数字电视传输与组网,人民邮电出版社,2003
14.(美)普罗克斯 等著,刘树棠 译,现代通信系统(MATLAB版)(第二版)——国外电子与通信教材系列,电子工业出版社,2005
15.余兆明,余智,数字电视原理,人民邮电出版社,2004
2.ATSC Standard A/52(1995),Digital Audio Compression(AC-3).
3.ATSC Document A/54(1995),Guide to the Use of the ATSC Digital Television Standard.
4.ISO/IEC IS 13818-1,International Standard(1994),MPEG-2 Systems.
5.ISO/IEC IS 13818-2,International Standard(1994),MPEG-2 Video.
6.Bhasker J.,A Verilgo HDL Primer(Second Edition),2001.
7.Bhasker J.,Verilgo HDL Synthesis:A Practical Primer,Star Galaxy Publishing,PA,1998,ISBN 0-9650391-5-3.
8.IEEE Standard Hardware Description Language Based on the Verilog Hardware Description Language,IEEE Std 1364-1995,IEEE,1995.
9.Proakis,J.G,数字通信.英文版(第四版),电子工业出版社,2004
10.樊昌信,曹丽娜,通信原理(第6版),国防工业出版社,2006
11.王新梅,肖国镇,纠错码:原理与方法(修订版)——21世纪高等学校通信类系列教材,西安电子科技大学出版社,1991
12.王伟,Verilog HDL程序设计与应用,人民邮电出版社,2005
13.余兆明,余智,数字电视传输与组网,人民邮电出版社,2003
14.(美)普罗克斯 等著,刘树棠 译,现代通信系统(MATLAB版)(第二版)——国外电子与通信教材系列,电子工业出版社,2005
15.余兆明,余智,数字电视原理,人民邮电出版社,2004