Water sound frequency hopping communication method for linear modulation signal modulation and demodulation

A linear frequency modulation signal, modulation and demodulation technology, applied to electrical components, transmission systems, etc., can solve the problem of fractional Fourier spectrum sampling value reduction, etc., to improve frequency band utilization, simple calculation process, and increase information transmission rate Effect

Inactive Publication Date: 2014-04-02
XIAMEN UNIV
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Problems solved by technology

[0025] When there is a Doppler shift f d When , the peak position moves, causing the sampling value of the fractional Fourier spectrum at the sampling position to decrease

Method used

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  • Water sound frequency hopping communication method for linear modulation signal modulation and demodulation
  • Water sound frequency hopping communication method for linear modulation signal modulation and demodulation
  • Water sound frequency hopping communication method for linear modulation signal modulation and demodulation

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Embodiment Construction

[0051] Below in conjunction with accompanying drawing, invention is described in further detail.

[0052] figure 1 A functional block diagram of an embodiment of the invention is shown. The communication transmitter first uses the original source as the source code to obtain the compressed digital signal, and performs channel coding on the compressed digital signal. The coding can be coded by convolutional code, Turbo code, etc.

[0053] The digital signal after channel coding is modulated by 4FH-LFM modulation method, and the modulation pattern of the chirp signal of each frequency hopping group is shown in figure 2 , image 3 , the decimal information represented by each chirp signal is correspondingly marked below the pattern. The system sampling rate fs is set to 96kHz, the frequency range is 10-20kHz, the number of frequency hopping is 4, the frequency hopping pattern is sequentially increasing, the symbol width is 10ms, and the communication rate is 600bps. The bina...

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Abstract

The invention provides a water sound frequency hopping communication method for linear modulation signal modulation and demodulation, and relates to a water sound frequency hopping communication. The water sound frequency hopping communication method comprises the following steps: carrying out source encoding on original information so as to obtain compressed digital signals; carrying out channel coding; using data obtained by the channel coding as a linear modulation signal control code; controlling to generate a linear modulation signal according to a frequency hopping sequence as a carrier for modulation, so as to obtain modulation signals; carrying out D/A (Digital/Analogue) conversion and power amplification on the modulation signals; converting the modulated signals into sound waves to spread in an ocean underwater acoustic channel through a transmission energy converter; receiving and converting acoustic signals spreading in the ocean underwater acoustic channel into electric signals through the receiving energy converter; obtaining stimulation signals through front amplification and band-pass filtering; carrying out A/D (Analogue/Digital) conversion on the received stimulation signals; after detecting that the digital signals after the A/D conversion are synchronous, carrying out linear modulation signal demodulation center frequency and demodulation frequency to obtain demodulation data; and carrying out channel decoding on the demodulation data; and carrying out source decoding on the digital signals to obtain information.

Description

technical field [0001] The present invention relates to underwater acoustic frequency hopping communication, in particular to a chirp using the inverse multiplication method to decompose the center frequency of the chirp signal and refining the discrete fractional Fourier transform (Zoom-DFRFT) to decipher the frequency modulation of the chirp signal The underwater acoustic frequency hopping communication method of signal modulation and demodulation. Background technique [0002] In traditional underwater acoustic frequency hopping communication, the carrier frequency is often used to carry information. Compared with other modulation methods such as MPSK, MFSK modulation frequency band utilization is relatively low, and its information transmission rate is relatively backward under the same bandwidth, but its robust and reliable performance makes it occupy an important place in underwater acoustic communication. Therefore, improving the frequency band utilization of the und...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/713
Inventor 涂星滨许肖梅邵志文陶毅张小康
Owner XIAMEN UNIV
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