| With the rapid development of water transport and sharp increase of ship density, vessel traffic services (VTS) has been introduced to the maritime departments of current major ports. With the coming of information era, several technologies which take computer as kernel are widely used in VTS system. As a significant component of VTS system, the very high frequency (VHF) radiotelephony subsystem ensures the basic speech communication functions of VTS. However, traditional VHF speech processing methods cannot satisfy the developing demands of modern VTS system in many aspects, including speech recording, reappearance and integration of speech system with VTS.To adapt to the requirements of VTS modernization, the subjected is proposed according to the practical needs of "Beichangshan radar renovation project" and "Jingzhou Yangtze River Bridge anti-crash surveillance system". This paper focuses on Multi-Band Excitation (MBE) speech coding-decoding method used by speech system. MBE is a parameter coding method based on analysis-synthesis. It subdivides the spectrum of a frame speech data to several sub-bands and estimates parameters in sub-bands. According to the voiced/unvoiced judgment of each sub-band, different excited source in composing speech is applied. Based on this theory, an independent speech processing system is built. Critical technologies to realize the system is discussed and studied in the paper, as well as their implement procedures. The system has multiple functions, including continuous recording and storage of the speech data, high-performance real-time compression of original speech, rapid location of specific speech using time and number of speech channels, real-time decompression and play of the compressed speech data.This paper introduces modern advanced technologies on speech-processing to VTS system, solving some present problems in the system; Meanwhile, the speech-processing system realized in the paper can be used in other fields with great applicable value. |
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