Segmented in-band modulation method for FM radio band digital analog mixed signal

A technology of FM broadcasting and digital-analog mixing, applied in the direction of multi-carrier systems, etc., can solve the problems of mutual interference of two signals, achieve the effect of improving demodulation signal-to-noise ratio and distortion index, and solving mutual interference

Active Publication Date: 2013-03-06
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 int...

Method used

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  • Segmented in-band modulation method for FM radio band digital analog mixed signal
  • Segmented in-band modulation method for FM radio band digital analog mixed signal
  • Segmented in-band modulation method for FM radio band digital analog mixed signal

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Embodiment Construction

[0030] The embodiment of the in-band segmental modulation method of the FM radio (FM) frequency band digital-analog mixed signal will be described in detail below in conjunction with the accompanying drawings.

[0031] figure 1 It is a schematic diagram of the in-band frequency spectrum of the digital audio broadcasting signal in the FM broadcasting frequency band in this embodiment. In this example, the FM broadcasting frequency band has a bandwidth of 200KHz, that is, -100KHz to +100KHz, and 0KHz is the midpoint of the frequency band. The 200KHz of the FM radio frequency band is divided into 5 sub-bands, such as figure 1 As shown, with the analog sound broadcasting signal potential 3.5μV as the set value,

[0032] In the -50~50kHz sub-band, the sub-carrier of the sound data symbol contained in the digital sound broadcasting signal is set to zero,

[0033] In the -50~-75kHz and 50~75kHz sub-bands, the analog sound broadcast signal potential is higher than 3.5μV, and the sou...

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Abstract

The invention relates to a segmented in-band modulation method for FM (frequency modulation) radio band digital analog mixed signals, in which analog sound broadcasting signals and digital sound broadcasting signals are combined to digital analog mixed signals which share an FM band. The FM band includes a plurality of sub-bands. For the digital sound broadcasting signals, sub-carriers are set to zero in an intermediate sub-band, or only synchronization symbol sub-carriers are retained; modulation modes in different orders are used in other sub-bands, and the distribution of sub-carriers of the sub-bands forms mirror symmetry to the center of the sub-bands, that is, the higher the modulation order is, the farther the distance is to the center. The synchronization symbol sub-carriers of the digital sound broadcasting signals are equally spaced and are modulated in an order lower than 24. Sound data symbol sub-carriers of the digital sound broadcasting signals are modulated in an order lower than 24 in a sub-band where the potential of analog signals is higher than 3.5 mu V. On the contrary, the sound data symbol sub-carriers of the digital sound broadcasting signals are modulated in an order higher than or equal to 24. The segmented in-band modulation method for FM radio band digital analog mixed signals has the advantages that the demodulation signal-to-noise ratio and the distortion index of analog signals of an FM digital analog mixed system are obviously improved, and the interference of digital analog signals in band same-frequency broadcasting signals is effectively eliminated.

Description

technical field [0001] The invention relates to the technical field of wireless broadcasting, in particular to an in-band segmental 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 d...

Claims

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Application Information

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IPC IPC(8): H04L27/32
Inventor 门爱东陈曦张光华王飞李立
Owner SHENZHEN SIKAIWEI ELECTRONICS CO LTD
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