| The radar receiver is very important in radar systems. It is mainly to achieve functions of received signal amplification, frequency conversion, filtering and digital processing. In practice, it eliminates the interfering noise, retains the useful signal, and ultimately sends the received signal into signal processing. The most popular digital receivers nowadays directly perform the intermediate frequency (IF) ADC transform of the input signal, then process the digital signal, and finally restore the original signal.This thesis chose the intermediate frequency coherent radar receiver system as the research subject. Firstly, the thesis analyzed the design and main technical performance of the intermediate frequency coherent radar receiver, introduced the system function and theory, described in detail the receiver dynamic range, image rejection and DC suppression, filtering and extraction method and thoroughly analyzed the technical difficulties of the IF coherent receiving system; the MATLAB simulation was performed. Secondly, the implementation of the research project was proposed. The composition of the system and its block diagram were discussed, and the functions of various components of the receiving system and its performance parameters were analyzed. Moreover, the composition, structure and design of the system was investigated. The final results showed that the scheme was practicable.Finally, the analysis of the MATLAB simulation results showed that background noise of the final output I_D, Q_D data was between30-40db. The DC component would cause DC high frequency noise between30-40db, which would be filtered out in the next level signal processing. In summary, the experiments result indicated that the signal noise data transmission by the digital receiver met the design requirements and carried the complete and sufficient signal information. |
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