10384 B200034014 UDC ( ) 2003 4 2003 6 2003
( )
5 Q I
Abstract Abstract Since sound is the only effective information carrier for medium or long distance wireless communication in sea water, underwater acoustic (UWA) communication plays an important role in national defense and in the development of marine economy. With the characteristics of large ambient noise, very narrow bandwidth, low carrier frequency, great propagation latency and time-space-frequency variant multipath effect (MPE), the stochastic ocean channel has demonstrated the greatest complexity and difficulty for underwater acoustic wireless communications. Among them multipath effect (MPE) is the most difficult obstacle that results in signal fading and inter-symbol interference (ISI). Upon the request from some institutions that have the practical needs for UWA applications, the research is conducted to achieve the objective of developing a digital underwater acoustic voice communication system with longer working distance. The nature of the multipath effect (MPE) has decided that phenomenon that the longer the working distance is adopted, the worse the multipath effect (MPE) plays the role. New methods should be studied and employed to eliminate or mitigate the negative resulted by multipath effect (MPE). It has been proven that the Spread Spectrum Technologies have good capabilities of overcoming ISI in electromagnetic wireless channel. The feasibilities of their applications to underwater acoustic channel have been analyzed, the Frequency Hopping technology is chosen. Instead of using time-frequency diversity, convolutional coding and Viterbi decoding are employed to combat signal fading, consequently the bit-rate and bit-error-rate performance of the underwater acoustic voice communication system can be balanced and controlled. For medium or long distance underwater acoustic communication, the narrow bandwidth and low carrier frequency only supports low bit-rate signal transmission. In order to achieve real time communication, Speech Recognition technology is used to keep the semantic information, meanwhile the greatest compression on the information is obtained. Consequently the data rate needed on the channel is reduced dramatically. When the semantic information is received, Speech Synthesis is used to generate highly clear voice in the receiver. Synchronization is the commander of every digital communication system, without it the system is unable to work orderly and correctly. A five-tuple of time-frequency diversity is adopted to guarantee that the synchronization signal be retrieved reliably in the receiver. II
Abstract An innovative and novel concept of Communication Sonar Equation (CSE) is introduced in the dissertation. According to the Communication Sonar Equation (CSE), all solutions for improving the working range of underwater communication system are fully discussed. Considering the restrictions in practical application, some methods are confirmed, others are discarded. During the R&D process of the system, a new type of High Q Bandpass Filter with self-calibration and integrate and dump is designed, which is cooperated with instantaneous frequency analysis to greatly improve the resolution and reliability of signal detection. That is another highlight of innovation in the study. The performance of the system has been investigated both in the laboratory s pool and on sea trials in real ocean environments at Xiamen bay coast. The results have indicated that the new generation of underwater acoustic voice communication system has the capability to overcome the severe multipath interference and has longer working range. It has been demonstrated that the objective of the research is achieved. Key Words: Underwater Acoustic Voice Communication, Multipath Effect, Diversity, Frequency-Hopping, Communication Sonar Equation, Instantaneous Frequency Analysis, Self-Calibration Bandpass Filter III
1 1.1 1 1.2 1 1.2.1 1 1.2.2 2 1.3 3 4 6 2.1 6 2.1.1 6 2.1.2 7 2.1.3 7 2.2 7 8 9 3.1 9 3.1.1 9 3.1.2 10 3.1.3 11 3.2 13 3.3 14 3.3.1 14 3.3.2 14 3.3.3 16 3.3.4 16 3.3.5 17 3.3.6 17 3.4 17 IV
3.4.1 17 3.4.2 19 3.5 20 3.6 22 3.7 24 3.8 24 24 26 4.1 26 4.1.1 26 4.1.2 26 4.2 27 4.2.1 28 4.2.2 28 4.2.3 29 4.2.4 29 4.3 30 4.4 30 4.4.1 30 4.4.2 IBM Via-Voice 30 4.4.3 IBM Via-Voice 33 4.4.4 TTS 33 34 35 5.1 35 5.2 36 5.2.1 36 5.2.2 36 5.2.3 37 5.2.4 37 5.2.5 39 5.3 40 5.3.1 41 5.3.2 42 5.3.3 44 5.3.4 49 5.3.5 Turbo 49 V
5.3.6 TCM 49 50 52 6.1 52 6.1.1 52 6.1.2 53 6.1.3 53 6.2 54 6.3 54 6.4 55 6.4.1 55 6.4.2 57 6.4.3 59 6.5 59 60 61 7.1 61 7.2 61 7.3 62 7.4 62 7.4.1 62 7.4.2 63 7.4.3 68 7.4.4 69 70 71 8.1 71 8.2 71 8.2.1 71 8.2.2 72 8.3 73 8.4 75 8.5 76 8.5.1 76 8.5.2 76 8.5.3 76 8.5.4 78 VI
8.5.5 79 8.5.6 80 8.5.7 81 8.6 81 82 84 9.1 84 9.1.1 84 9.1.2 87 9.2 90 9.2.1 90 9.2.2 90 9.2.2 91 9.2.3 91 9.2.4 92 9.2.5 94 9.2.6 96 9.3 96 9.3.1 96 9.3.2 96 9.3.3 97 9.3.4 98 9.3.5 Q 102 9.3.6 103 9.3.7 DSP 103 9.3.8 Viterbi 107 9.3.9 107 9.3.10 107 9.3.11 108 9.4 109 109 112 10.1 112 10.2 113 10.2.1 113 10.2.2 115 10.2.3 116 VII
10.3 117 10.4 117 10.4.1 117 10.4.2 118 119 1 120 [ 1-A] 120 [ 1-B] 123 2 DSP 125 [ 2-A] 125 [ 2-B] 127 [ 2-C] DSP 127 [ 2-D] 128 3 132 [ 3-A] 132 [ 3-B] 134 136 VIII
2-1 6 3-1 9 3-2 10 3-3 10Hz 100KHz 12 3-4 5KHz 15KHz 12 3-5 15 3-6 16 3-7 Wenz 18 3-8 18 3-9 19 3-10 19 3-11 20 3-12 20 3-13 21 3-14 21 3-15 22 4-1 29 4-2 30 4-3 IBM Via-Voice 31 5-1 40 5-2 40 5-3 41 5-4 45 5-5 2,1,2 47 5-6 Viterbi 48 6-1 54 6-2 54 6-3 55 6-4 55 6-5 56 6-6 57 7-1 62 7-2 a 7K5 9000m 4 63 IX
7-2 b 9K5 9000m 4 63 7-3 64 7-4 65 7-5 66 7-6 67 7-7 68 7-8 69 7-9 69 8-1 72 8-2 73 8-3 74 8-4 75 8-5 75 8-6 1# 76 8-7 2# 77 8-8 3# 78 8-9 4# 78 9-1 84 9-2 84 9-3 85 9-4 85 9-5 9000m 7K5 89 9-6 9-5 89 9-7 90 9-8 90 9-9 2,1,2 91 9-10 93 9-11 95 9-12 96 9-13 97 9-14 B 97 9-15 4 ISP 98 9-16 99 9-17 99 9-18 101 9-19 102 9-20 102 X
9-21 Q 103 9-22 X (k) 104 9-23 X (k) 105 9-24 106 9-25 107 9-26 9-23 108 9-27 108 10-1 59H Ch2 113 10-2 3 114 10-3 a 114 10-3 b 115 10-4 5km 115 10-5 10km 116 10-6 12km 116 10-7 12km Q 117 A1-1 AN/WQC-2A 120 A1-2 AN/WQC-2A 120 A1-3 121 A1-4 Benthos 3 121 A1-5 LinkQuest Modem 122 A1-6 TIVA 123 A1-7 MATS 123 A2-1 125 A2-2 126 A2-3 127 A2-4 DSP 128 A2-5 129 A2-6 129 A2-7 130 A2-8 130 A2-9 131 A2-10 131 A3-1 132 A3-2 133 A3-3 133 XI
A3-4 134 A3-5 134 A3-6 135 XII
3-1 9 3-2 10km 13 4-1 27 4-2 28 5-1 35 5-2 2,1,2 47 8-1 79 8-2 SL 79 V 8-3 SL 80 W 8-4 ML 81 p 9-1 86 9-2 87 9-3 88 9-4 91 XIII
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