DRM嵌入式接收机软件关键技术实现

发布时间：2019-01-07 22:08

【摘要】：DRM(Digital Radio Mondiale)系统是频率在30MHz以下的多媒体数字无线广播系统。DRM采用OFDM调制方式和多级信道编码,信源编码等通信领域新技术,既充分利用了30MHz以下广播频段覆盖范围广、传播距离远的优势,又克服了传统的模拟调幅广播抗干扰能力差,发射功率大,业务单一等固有技术缺陷。在与模拟调幅广播同样的带宽(9 k或10 kHz)下实现了调频的音质,而且在音频业务的基础上增加了文本、图像等附加的数据业务,丰富了调幅广播的内容。 DRM信源解码和数据业务解码的正确实现决定了用户能否得到质量良好的音频以及丰富的增值业务,因此信源解码和数据业务解码的研究与实现对DRM接收机的整体实现具有重要的意义。此外,目前的接收机多为专用接收机和软件接收机,为数不多的便携式接收机也由于实现复杂而价格过高,并没有真正的实现大范围推广,因此研究DRM嵌入式接收机系统具有重要的实际应用意义。本文介绍了DRM系统音频业务解码以及数据业务中文本信息和静态图片解码的原理和实现方法,并介绍了DRM系统的信道估计、FFT解调以及linux系统下音频播放功能的实现方法。本文的开发平台是基于DM3730内核的Beagleboard-xM嵌入式开发平台,该平台集成了功能强大的主频1GHz的ARMCortex-A8内核和主频800MHz的TMS320C64+数字信号处理器,适合作为DRM软件接收机平台。论文基于该平台实现了linux系统下的DRM嵌入式接收机的音频解码和数据解码,通过软件优化,成功的在嵌入式开发板上得到清晰流畅的音乐和语音节目,解码后得到的音频文件与编码前的源文件比较,证明其误比特率性能良好。
[Abstract]:DRM (Digital Radio Mondiale) system is a multimedia digital radio broadcasting system with frequency below 30MHz. DRM adopts new communication technologies such as OFDM modulation mode, multilevel channel coding, source coding and so on, which make full use of the wide coverage of broadcast frequency band below 30MHz. The advantage of long propagation distance overcomes the inherent technical defects of traditional analog AM broadcasting, such as poor anti-jamming ability, large transmitting power, single service, and so on. In the same bandwidth (9 k or 10 kHz) as analog AM broadcast, the FM sound quality is realized, and the additional data services such as text and image are added to the audio service, which enriches the content of AM broadcast. The correct implementation of DRM source decoding and data service decoding determines whether the user can get good quality audio and rich value-added services. Therefore, the research and implementation of source decoding and data decoding is of great significance to the overall implementation of DRM receiver. In addition, most of the current receivers are dedicated receivers and software receivers, and a small number of portable receivers are expensive because of the complexity of their implementation, and have not really been widely promoted. Therefore, the study of DRM embedded receiver system has important practical significance. This paper introduces the principle and implementation method of audio service decoding in DRM system, Chinese text information and static picture decoding of data service. It also introduces the channel estimation of DRM system, FFT demodulation and the realization of audio playback function in linux system. The development platform of this paper is the Beagleboard-xM embedded development platform based on the DM3730 kernel. The platform integrates the ARMCortex-A8 kernel of the main frequency 1GHz and the TMS320C64 digital signal processor of the main frequency 800MHz, and is suitable for the DRM software receiver platform. Based on this platform, the audio decoding and data decoding of DRM embedded receiver in linux system are realized. Through software optimization, clear and smooth music and voice programs are successfully obtained on the embedded development board. The comparison between the decoded audio file and the source file shows that the bit error rate (BER) is good.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP368.1;TN851

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