Intermediate frequency modulation and demodulation method for digital T/R assembly

A modulation and demodulation and component technology, which is used in multi-frequency modulation and conversion, radio wave measurement systems, instruments, etc., can solve the problems of complex circuits, difficulty in integrated miniaturization design, and large size, and achieve high resolution, timely and effective storage and storage. The effect of processing, low price

Active Publication Date: 2021-04-09
NO 20 RES INST OF CHINA ELECTRONICS TECH GRP
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  • Abstract
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  • Application Information

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Problems solved by technology

The circuit of these methods is too complicated and huge, which brings great difficulty to the integrated miniaturization design.

Method used

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  • Intermediate frequency modulation and demodulation method for digital T/R assembly
  • Intermediate frequency modulation and demodulation method for digital T/R assembly
  • Intermediate frequency modulation and demodulation method for digital T/R assembly

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Embodiment Construction

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] In launch state, see figure 1 , in a radar cycle, the DDS transmits a waveform of 3 signals f with an interval frequency of 15MHz at a certain interval 1 , f 2 , f 3 , requiring not only frequency modulation but also phase modulation. The initial state of the frequency sweep transmitting signal is determined by the frequency word, phase word, amplitude word and other control registers, and the sweep state is determined by the frequency scan rate register, scan rate timer clock and scan frequency step word register. Transmitting three frequency sweep signals with different frequencies and different pulse widths in one radar cycle means that the DDS frequency word, frequency scan rate register, scan rate timer clock and scan frequency step word register must be completed within a limited time Configuration. In order to solve the above difficul...

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Abstract

The invention provides an intermediate frequency modulation and demodulation method for a digital T / R assembly. The method comprises the steps: transmitting N types of swept-frequency signals with different frequencies and different pulse widths in one radar period during the modulation and demodulation of a digital intermediate frequency signal through employing a DDS and DDC digital processing method, completing the configuration, and controlling a DDS chip through a digital circuit, thereby achieving the modulation and demodulation of the digital intermediate frequency signal. The configuration speed is improved by shortening the total configuration time, during receiving, intermediate frequency signals are generated after signal down-conversion, data of sampled digital signals are sent to the FPGA, orthogonal demodulation is conducted on the sampled digital signals in the FPGA, and zero intermediate frequency signals are subjected to matched filtering through the low-pass filter and sent to the signal processing subsystem. According to the invention, the blind compensation splicing points become smoother, so that the efficiency of the transmitter is exerted to the greatest extent, the cost performance of the frequency synthesizer is improved, and very high I / Q orthogonal sampling precision and stability are obtained.

Description

technical field [0001] The invention relates to the field of digital modulation and demodulation, in particular to a method for three-coordinate radar to transmit multiple pulses to realize distance blindness compensation. The present invention adopts the digital processing method of direct digital frequency synthesis technology DDS (Direct Digital Frequency Synthesis) and digital down-conversion DDC (Direct Digital Controller) to complete the modulation and demodulation of digital intermediate frequency signals. Background technique [0002] With the development and demand of technology, higher requirements are put forward for radar performance indicators such as operating distance, resolution and speed measurement accuracy at this stage. The detection ability of radar is proportional to the average power of radar emission. In the case of device load limitation, increasing the average power is generally achieved by increasing the emission pulse width. In order to meet the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03D7/16G01S7/28
CPCH03D7/16G01S7/2813
Inventor 宋锐桂阳
Owner NO 20 RES INST OF CHINA ELECTRONICS TECH GRP
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