Underwater acoustic communication method based on mode frequency modulation

A technology of underwater acoustic communication and FM signal, applied in multi-frequency code systems, electrical components, transmission systems, etc., can solve the problems of relatively large differences in fundamental frequency curves, achieve low interception rates, improve resolution capabilities, and improve frequency spectrum Effect of Utilization and Communication Data Rate

Inactive Publication Date: 2012-08-08
SOUTH CHINA UNIV OF TECH
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Problems solved by technology

This is similar to the fundamental frequency curve of a tone. Although there is a frequency deviation at a single point frequency in the fundamental frequency curve of a female voice relative to a male voice, the fundamental frequency curve still has a very similar relative shape for the same tone. Tone, the relative shape of the fundamental frequency curve is quite different

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  • Underwater acoustic communication method based on mode frequency modulation
  • Underwater acoustic communication method based on mode frequency modulation
  • Underwater acoustic communication method based on mode frequency modulation

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Embodiment Construction

[0044] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific implementation examples, but the embodiments of the present invention are not limited thereto.

[0045] (1) Assuming that m represents the number of bits contained in each symbol, the design consists of M=2 m A frequency modulation pattern group (also known as a frequency modulation curve group) composed of frequency modulation curves of different modes: that is, M frequency modulation curves f i (t)(i=1, L, M), representing M different binary symbols. At the same time, the eigenvector library corresponding to the frequency modulation mode group is obtained

[0046] In order to describe the present invention more clearly, it is assumed that each symbol carries m=3 bits of information, and two straight lines and the i-th harmonic of the sinusoidal signal are used as the signal frequency modulation curve as an example to describe how the frequency ...

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Abstract

The invention provides an underwater acoustic communication method based on mode frequency modulation, which comprises the following steps: carrying out frequency modulation on transmitted signals by adopting frequency modulation curves with different modes and further carrying different symbol information through the frequency modulation curves with the different modes. The underwater acoustic communication method has the advantages that the different transmitted signals are carried at the transmitting end by adopting the different modes of the frequency modulation curves to eliminate traditional frequency modulation technology; by adopting a special frequency modulation mode group, when the receiving end classifies time frequency curves, the interference caused by noise can be resisted, so that the requirements on instantaneous frequency estimation precision are effectively reduced; and when the receiving end judges transmitted symbols by adopting an instantaneous frequency estimation algorithm and in combination with an automatic mode recognition classifier, and the orthogonality among the transmitted frequency modulation signals is not required, and the different information can be carried by using a plurality of frequency modulation modes in a same frequency band, so that the frequency spectrum utilization rate and the communication data rate are effectively improved.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication, in particular to a mode frequency modulation-based narrow-band nonlinear frequency modulation communication method applied in long-range (>10km) low-speed underwater acoustic communication. Background technique [0002] With the development of ocean resources in various countries in the world today, whether it is military or civilian, the development demand for underwater acoustic communication technology is becoming more and more urgent. However, the underwater acoustic channel is one of the most complex of all communication channels. The signal frequency offset caused by multipath interference and Doppler effect in underwater acoustic environment seriously affects the performance of underwater acoustic communication. Since the attenuation of underwater acoustic communication signals increases with the increase of frequency, the frequency band used in underwater acoustic comm...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/711H04B13/02H04L27/26
Inventor 韦岗曹晓珊杨萃曹燕
Owner SOUTH CHINA UNIV OF TECH
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