Design Of The Civil Air Defense Alarm Spread Spectrum Receiver Based On FPGA

Future wars will be led by informatization wars,so the key point of civil air defense construction naturally focused on the anti-electromagnetic interference and the improvement of accuracy of air defense warning signals.As the existing alarm communications system is based on narrowband communications technology and the interference effects the narrow-band communication system a lot,thus caused the bit error rate increased and the reliability of communication reduced.With the development of the spread spectrum communication technology and its advantages in communication transmission,it has been used gradually in the civil air defence alarm.Moreover,with the development of modern integrated circuits and microelectronic design and process technology,create beneficial conditions for the establishment of functional and technological progress and highly inteligent alarm control system.FPGA,due to its advantages,such as high integration and rich logical resources and can carry out complex signal processing,has been implemented in the civil air defense alarm system.This paper,according to the analysis of the principle of spread spectrum communication technology and related knowledge and the requirements of the civil air defense alarm communication,puts forward the idea of using FPGA to realize the spread spectrum civil air defense alarm spread spectrum receiver.This paper focused on the design of digital processing of the alarm signal receiver,by the analysis of actual demand,we select the appropriate despreading and demodul-ation method.And we choose EP1C12Q240C8 N as the core processing chip,using related mapping software to complete the outer circuits of the civil air defense alarm spread spectrum receiver,such as power supply circuit,clock circuit,reset circuit,the external expansion memory circuits and alarm circuits and related hardware circuit design,all the circuits have detailed description.We also have the relevant software design based on Quartus ? software platform,using the schematic and VHDL language to design the digital down-conversion module,the pseudo code acquisition module,the pseudo code tracking module,carrier phase synchronization module,despreading and demodulation module and related design of signal processing modules.This paper provide theoretical basis and design ideas for the producibility of the spread spectrum civil air defence alarm spread spectrum receiver.