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Information modulation and demodulation method of high frequency band utilization rate

A technology for information modulation and utilization, applied in the field of digital information transmission, it can solve the problems of modulation efficiency and complex processing that have not yet been seen, and achieve the effect of adapting to wide area, flexible control, and improving reliability.

Inactive Publication Date: 2004-05-05
北京驰信畅达科技有限公司
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Problems solved by technology

This is usually achieved by increasing the number of constellation points in the signal space as much as possible, such as multi-level quadrature amplitude phase modulation (MQAM) and multi-phase shift keying (MPSK) modulation methods, but the processing is relatively complicated, and has not yet been seen. Reports that its modulation efficiency exceeds 20bit / s / Hz

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  • Information modulation and demodulation method of high frequency band utilization rate
  • Information modulation and demodulation method of high frequency band utilization rate
  • Information modulation and demodulation method of high frequency band utilization rate

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Embodiment Construction

[0028] The present invention directly changes a waveform symmetry parameter α of the sinusoidal carrier by using the binary information symbol, so that the waveform difference between the modulated signal and the sinusoidal signal is minimized, and the information transmission rate is equal to the carrier frequency. The waveform modulated by logic "0" is g(t, τ), and the waveform modulated by logic "1" is g(t, T-τ):

[0029]

[0030] Here T is the period of the signal waveform, which is also the symbol width and symbol width of information; and f=1 / T is the frequency of the signal waveform, which is also equal to the transmission rate of the symbol in value; the modulation waveform itself has the following technology feature:

[0031] ① The waveform is defined in two sections, each of which is a half period of a sine wave, but the amplitudes are A / τ and A / (T-τ), and the periods are 2τ and 2(T-τ);

[0032] ②The degree to which the carrier is modulated varies with τ; if τ=αT...

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Abstract

The method changes symmetric parameter of waveform alpha directly by using binary information code-element so as to reach minimum difference between waveforms of modulated signal and sine signal, its information transmission rate is equal to carrier frequency. Waveform g(t, iota) is modulated by logic '0', and waveform g(t, T-iota) is modulated by logic '1'. Here, T is cycle of signal waveform, also is symbol width and code-element width of information, and f=1 / T is frequency of signal waveform, or equal to transmission rate of code-element in numerical value. Since information transmission rate is euqal to carrier frequency, and transmission signal is very close to sine wave, thus, energy of frequency spectrum is concentrated highly so as to use very narrow bandwidth. The invented method possesses features of very high utilization rate of frequency band, and applicable to high-speed digital transmission in ultra narrow bandwidth.

Description

technical field [0001] The invention relates to an information modulation method for digital communication, belonging to the technical field of digital information transmission. Background technique [0002] In order to realize long-distance transmission of digital information, binary data must be loaded onto a high-frequency signal (carrier), this process is called modulation, and the opposite process is called demodulation. Since the modulated high-frequency signal (modulated wave) occupies a certain frequency bandwidth (signal bandwidth), in order to transmit the modulated wave more reliably, it must also occupy a corresponding frequency bandwidth (transmission bandwidth). However, frequency is a non-renewable precious resource. In order to achieve the highest possible frequency band utilization, it is necessary to improve the modulation efficiency when converting digital signals to analog channels, so that more frequencies can be transmitted wit...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/49H04L27/00H04L27/12
CPCH04L27/12H04L25/4906
Inventor 吴乐南李小平司宏伟张士凯
Owner 北京驰信畅达科技有限公司
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