Design of 2FSK Modulator for Balise Dynamic Detection System Based on Improved DPS
The balise dynamic detection system based on the high speed comprehensive inspection train platform can implement real-time performance inspection of balise related equipment.To test the performance of the onboard balise dynamic detection system,it is necessary to generate high-precision modulated signals(2FSK)with controllable baud rates and carrier frequencies and use them as uplink signals.Based on direct digital synthesizer(DDS)technology,a segmented phase accumulation algorithm was developed by designing a phase accumulation module and a phase-amplitude conversion module.Additionally,the phase increment within the same period and that at the symbol jump were calculated.Furthermore,the signal amplitude was calculated in real time with an improved coordinate rotation digital computer(CORDIC)algorithm,and the discrete signals were converted into analog signals using a digital-to-analog converter(DAC)to modulate signals with variable frequency offset and data rate and continuous phase.In the design of the phase-to-amplitude conversion module,an improved CORDIC algorithm was used instead of the traditional look-up table method to convert phase increment to signal amplitude.This process effectively reduced the storage resource overhead of field programmable gate array(FPGA).The design of 2FSK modulator based on improved DDS can provide high-precision 2FSK modulated signals with controllable baud rates and carrier frequencies for the balise dynamic detection system,ensuring its calibration accuracy.
NETL
NSTL
万方数据
