Self-adaptive in-band modulation method of digital and analog mixed signals of frequency-modulation broadcast frequency range

A technology of FM broadcasting and digital-analog mixing, applied in the field of broadcasting, can solve the problem of mutual interference between two kinds of signals

Active Publication Date: 2013-03-27
SHENZHEN SIKAIWEI ELECTRONICS CO LTD
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Problems solved by technology

[0011] However, none of the existing solutions can completely solve the problem of mutual interference between the two signals in the digital-analog mixed signal in the FM radio frequency band.

Method used

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  • Self-adaptive in-band modulation method of digital and analog mixed signals of frequency-modulation broadcast frequency range
  • Self-adaptive in-band modulation method of digital and analog mixed signals of frequency-modulation broadcast frequency range
  • Self-adaptive in-band modulation method of digital and analog mixed signals of frequency-modulation broadcast frequency range

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Embodiment Construction

[0052] An embodiment of an adaptive in-band modulation method for an FM broadcast frequency band digital-analog mixed signal will be described in detail below in conjunction with the accompanying drawings.

[0053] The frequency range of FM broadcasting in my country is 87-108MHz. In order to prevent mutual interference between FM stations, the channel interval between stations is stipulated as 200kHz, the maximum frequency deviation is 75kHz, and the maximum modulation signal frequency is 15kHz. In addition to being used for sound broadcasting, analog FM broadcasting can also use FM broadcasting subcarriers (67kHz or 92kHz) to carry out data services (Subsidiary Communication Authorization, SCA).

[0054] my country's national standard (GB4322.3-84) stipulates that in FM broadcasting, the frequency of 0~15kHz is the main channel; 23~53kHz is used to transmit the difference signal of stereo broadcasting, and its subcarrier frequency is 38kHz; 19kHz is used to transmit the pilot...

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Abstract

The invention relates to a self-adaptive in-band modulation method of digital and analog mixed signals of a frequency-modulation broadcast frequency range. The self-adaptive in-band modulation method includes that analog sound broadcast signals and digital sound broadcast signals which are respectively generated are synthesized to generate a channel of analog and digital mixed signals to share a same frequency-modulation broadcast frequency range, and is characterized in that an FM (frequency modulation) frequency range is divided into a plurality of sub-frequency range so as to simulate characteristic parameters of sound broadcast signals to be self-adaptive parameters of digital sound broadcast signals, and sets a digital sound broadcast signal sub-carrier high and low-order modulation way in various sub-frequency ranges. The method includes steps that firstly, the FM frequency range is divided into three sub-frequency ranges on each side by being symmetric relative to a center; secondly, calculating simulated sound broadcast signal energy distribution in the FM frequency range; and thirdly, comparing the simulated sound broadcast signal energy En in each sub-frequency range with a preset threshold value, and determining the modulation way of the digital sound broadcast signals of each sub-frequency range. Demodulation signal noise ratio and distortion degree index of the simulated sound broadcast signals of an analog and digital mixing system are remarkably increased, and mutual interference of the analog and digital signals in the in-band same-frequency mixing broadcast signals is overcome.

Description

technical field [0001] The invention belongs to the technical field of broadcasting, and in particular relates to an adaptive in-band modulation method of a digital-analog mixed signal in an FM broadcast frequency band. Background technique [0002] At present, the digitization process of TV all over the world has been initially completed. my country's digital terrestrial broadcasting (Digital Television Terrestrial Broadcasting, DTTB), mobile multimedia broadcasting (China Mobile Multimedia Broadcasting, CMMB, that is, mobile phone TV) has entered a stage of steady development, while the digitalization of cable TV has been commercialized for many years, and is entering the two-way, high-definition era . Digitalization has brought higher-quality program production, transmission and reception, and digitalization has enabled users to enjoy a better user experience. When the digitalization of film, TV, mobile multimedia and many other media has achieved remarkable results, the...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 门爱东李栋陈曦王飞彭铁雁
Owner SHENZHEN SIKAIWEI ELECTRONICS CO LTD
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