The Design Of VHF-band Array Antenna And Receiving Front-end

This subject mainly undertakes on the development task of cloud lightning detection equipment, on specifically is the hardware realization of the array-antenna and eight-channel VHF-band array receiving front-end; The so-called array signal receiver is to set the number of antennas composed of different locations in space antenna array ,through of the array to receive and treat the spatial signal field, aimed to extract the signal received by the array and characteristics of information (parameters), while suppressing the interference and noise or not interested information; It enhance the signal through of the spatial characteristics and effectively extract the signal spatial information, so array signal receiving is also often called spatial signal receiving. It has a higher capacity, stronger anti-interference ability, higher spatial super-resolution capabilities than normal signal processing; For each channel receiver design is specialized superheterodyne receiving mode, channel primary design amplitude limit filtering protection circuit, adopt two-stage surface acoustic wave filter, adjustable intermediate frequency gain, variable this vibration signal, etc. The key to array channel design lies in ensuring channel consistency.In addition to regular calibration or calibration following the need according to channel calibration algorithm for external calibration,in the phase of hardware design, in the aspects of chip selection and PCB layout routing all give priority to ensuring the consistency of physical features and electrical characteristics between the signal channels, that's the key of the design's success or failure; all the chip's configuration or switch centralized control by the FPGA chips, FPGA chip resources seting aside take into account the needs of function Extension for future, It can upgrade firmware through the means of serial port, trigger bus, and ISP, the combination of hardware and software increase flexibility and expansibility of system. Through the actual board-level debugging, the IF differential signal can stable and consistent output, the phase difference between channels within the calibration range, Other indicators also meet the design requirements. The channel data receiving by the analog array receiver are sent to the AD device and digital processing circuit,the result of calculation has been able to supply a good positioning of the Lab thunder source, further verify the feasibility of the design and the circuit design.