Detecting and analyzing method for multi system frequency shift key control signal

A technology of frequency shift keying and analysis method, applied in transmission monitoring, modulation carrier system, frequency modulation carrier system, etc., can solve the problems of unfavorable system implementation, the power distribution of each symbol is not equal, not easy, etc.

Inactive Publication Date: 2007-04-11
TSINGHUA UNIV
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Problems solved by technology

[0050] ●This method assumes that the power distribution of each symbol is equal, but in the actual test environment, due to factors such as frequency selective fading, the power distribution of each symbol is often not equal;
[0051] ●When calculating DFT, the author declares to use as long as possible FFT length, which is not conducive to the realization of the actual system, and it is not easy to estimate a reasonable FFT length when the signal bandwidth is unknown

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  • Detecting and analyzing method for multi system frequency shift key control signal
  • Detecting and analyzing method for multi system frequency shift key control signal
  • Detecting and analyzing method for multi system frequency shift key control signal

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Embodiment Construction

[0136] The overall flow of the MFSK signal detection and analysis method proposed by the present invention is shown in Figure 1, comprising the following steps:

[0137] 1) Receive the data to be processed and obtain the real signal x(n);

[0138] 2) Turn the real signal x(n) into an analytical signal s(n);

[0139] 3) According to the predefined threshold, the s(n) amplitude is detected segmentally, and the weak signal segment is removed;

[0140] 4) Calculate the normalized instantaneous frequency sequence f of s(n) n (n);

[0141] 5) Calculate the rate of change sequence Δf of the normalized instantaneous frequency n (n) and its absolute value mean m Δfn ;

[0142] 6) will m Δfn Same as predefined threshold τ m compare if m Δ f n τ m , Then determine the signal as an MFSK signal, otherwise determine that the...

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Abstract

This invention relates to automatic identification to communication signals and analysis technology aiming at testing and analyzing multi-bit frequency shift key controlled signals characterizing in comparing the mean value of the absolute value of the variance rate sequence of the normalized instant frequencies with the set threshold value to judge MFSK signal, when analyzing, Smooth filtration is used in reducing shake of the MFSK signal transient frequency then the entropy principle is used in analyzing the histogram for the distribution of transient frequencies to estimate the state number of code elements and frequency sphere with an equal probability distribution principle then to use the equal frequency distance to get more accurate code element state number, frequency sphere and central frequency.

Description

technical field [0001] The invention belongs to the field of communication signal analysis, in particular to automatic identification and analysis of multi-ary frequency shift keying (MFSK) signals in digital modulation modes. Background technique [0002] Automatic identification of modulation mode is an important link in applications such as electronic warfare (communication reconnaissance), radio monitoring, and adaptive communication. It is also an important topic in the field of non-cooperative communication. Various theories of communication signal analysis have been widely used in this direction. Frequency shift keying modulation (FSK) plays an important role in shortwave / ultrashort wave communication and amateur radio communication of the army and government. It is an important digital signal modulation method. The detection and analysis of this type of signal is a radio signal monitoring And the important content of military communication reconnaissance. The invent...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/10H04L27/14H04L27/156H04B17/00
Inventor 邹红星俞力杰王普
Owner TSINGHUA UNIV
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