Frequency-residence differential frequency modulation keying modulated communication method

A technology of key modulation and communication method, which is applied in the direction of frequency modulation carrier system, etc., and can solve the problems of reducing the energy concentration of modulated signals, sudden changes in the frequency of modulated signals, and reducing frequency band utilization, etc.

Inactive Publication Date: 2010-08-04
HARBIN ENG UNIV
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Problems solved by technology

[0008] 3) VMCK modulation technology: Although the modulated modulation frequency is smooth and transitional within the symbol interval, the frequency of the modulated signal may change abruptly at symbol jumps
[0009] The discontinuity of the phase and the sudden change of the frequency will expand the spectrum of the modulated signal, reduce the energy concentration of the modulated signal, and thus reduce the frequency band utilization

Method used

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  • Frequency-residence differential frequency modulation keying modulated communication method
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  • Frequency-residence differential frequency modulation keying modulated communication method

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Embodiment Construction

[0059] The present invention is described in more detail below in conjunction with accompanying drawing example:

[0060] figure 1 It is a schematic diagram of FDDCK modulated signal frequency conversion. Depend on figure 1 It can be seen that the frequency rule of the FDDCK modulated signal is: when the data state remains unchanged, the frequency of the modulated signal remains unchanged, that is, the frequency resides; when the data state changes, the frequency of the modulated signal increases or decreases linearly.

[0061] figure 2 It is a schematic diagram of FDDCK modulated signal waveform. Depend on figure 2 It can be seen that the phase of the FDDCK modulated signal is continuous and the frequency is excessively smooth, which makes the smoothness of the modulated signal higher.

[0062] image 3 is the FDDCK modulated signal power density spectrum curve. Depend on image 3 It can be seen that the energy of the FDDCK modulated signal is mainly concentrated ne...

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Abstract

The invention provides a frequency-residence differential frequency modulation keying modulated communication method. The method comprises the following steps: calculating a frequency modulation coefficient alpha according to a frequency band utilization rate eta as a system required; calculating an upper limit frequency (f0+alphafs) and a lower limit frequency (f0-alphafs) of a modulated waveform sample according to the centre frequency f0, information transmission rate fs and modulation coefficient alpha of a modulated signal, and generating four modulated signal waveform samples; calculating the phase change quantities of the four modulated signal waveform samples in a code element interval; differentially selecting the modulated signal waveform samples according to bipolar binary data, calculating a primary phase phi iT of siT(t), and generating a modulated signal siT(t) of an ith code element; and generating a simulated modulated signal through a DA converter. The invention provides a digital modulation communication method with continuous phase and smooth transition frequency, which is a new band-pass ultra-narrow band communication method; and in the scheme, the energy of the modulated signal is mainly centralized nearby a carrier, the utilization rate of the frequency band is higher, and the high-speed data transmission is realized in an extremely narrow bandwidth.

Description

technical field [0001] The invention is a modulation and demodulation method for digital communication, is a novel band-pass ultra-narrowband modulation technology, and belongs to the field of digital communication. Background technique [0002] In the field of wireless digital communication, with the increasing demand for communication, the contradiction between communication rate and electromagnetic spectrum resources has become more and more serious, so a series of high-efficiency communication theories and their implementation technologies have emerged, so Orthogonal Frequency Division Multiplexing (OFDM) New theories and technologies that can improve the communication capacity of the system, such as high-efficiency digital modulation technology, multi-antenna (MIMO) technology, space-time coding technology, and ultra-wideband (UWB) technology, are constantly emerging. [0003] In 1997, the Very Minimum Shift Keying (VMSK) modulation proposed by Dr. H R Walker has higher...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/10
Inventor 孙志国周彬郭黎利
Owner HARBIN ENG UNIV
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