Ground digital TV five-channel merging modulator

A terrestrial digital TV, five-channel technology, applied in the direction of image communication, electrical components, selective content distribution, etc., can solve the problems of large number of hardware, high construction cost, low system stability, etc., and achieve hardware resources and overall machine performance The effect of reducing energy consumption, reducing construction costs and improving stability

Inactive Publication Date: 2017-01-18
焦桂花
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Problems solved by technology

The above-mentioned technical method requires a large amount of hardware, high construction cost, and low system stability

Method used

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  • Ground digital TV five-channel merging modulator
  • Ground digital TV five-channel merging modulator
  • Ground digital TV five-channel merging modulator

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Embodiment Construction

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] refer to figure 1 , a modulator for combining five channels of terrestrial digital television, comprising:

[0020] Power adjustment, using 0~-3dB power adjustment, 0.5dB step, multiplying the IQ of each channel by a fixed coefficient, which is the FPGA implementation of constant coefficient multiplication;

[0021] Constant coefficient multiplication replaces the hardware multiplier with an adder and a shifter. In order to further reduce the number of adders and shifters, the constant coefficient is encoded using Canonical Signed-Digital (CSD) encoding; CSD encoding is a ternary notation: any integer X can be encoded in CSD as , where C i is the element in the set {-1, 0, 1}.

[0022] The number of non-zero elements in a binary number is recorded as the weight of the number. The CSD code of a number is unique. Any two non-zero bit...

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Abstract

The invention provides a ground digital TV five-channel merging modulator which includes power adjustment, where 0-3dB power adjustment and 0.5dB stepping are employed to realize FPGA of IQ two paths of each channel multiplying by a fixed coefficient; upper sampling by inserting three zeros in each two sampling points to realize four-time up-sampling of baseband signals, and by suppressing mirror image frequency spectrum by a cascade Nyquist filter after interpolation; low-intermediate frequency modulation by employing a direct digital frequency synthesizer to generate orthogonal frequency signals required for modulating 15 frequency points; and merging amplitude limit by employing a ternary tree structure to optimize an adder, conducting amplitude limiting processing for the output of the adder, outputting to DA from orthogonal modulation and power amplification to radio frequency output. Compared with five independent modulators, the ground digital TV five-channel merging modulator has the same performance, substantially reduces cost and power consumption, and has higher practical value.

Description

technical field [0001] The invention belongs to the field of digital television, and in particular relates to a modulator for combining five channels of terrestrial digital television. Background technique [0002] Terrestrial digital TV is different from cable digital TV and satellite digital TV. It broadcasts and transmits digital TV signals through the establishment of transmitting base stations on the ground. A digital TV exciter can only transmit limited standard-definition or high-definition programs, which cannot meet people's viewing needs for dozens of programs. In the construction of existing terrestrial digital TV base stations, it is often necessary to configure multiple digital TV exciters, modulate each modulator to different VHF / UHF frequency bands, combine them at the radio frequency and send them out through the antenna, and complete the wireless transmission of multiple programs. broadcast. The above-mentioned technical method requires a large amount of h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N21/426
CPCH04N21/42676
Inventor 焦桂花
Owner 焦桂花
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