Research On The Key Technology Of The Broadband Electromagnetic Signal Direct Fourier Transform Based On The Dual Optical Frequency Combs

Discrete Fourier Transformation(DFT)is one of the powerful tools in Digital Signal Processing(DSP).With the continuous development of modern information science and technology,users’ demands for mass information transmission and processing are also increasing,which greatly increases the requirements for the speed and throughput of the DFT processor.The real-time DFT processor with high precision,high throughput and low power consumption is one of the key technologies for broadband electromagnetic signal acquisition and analysis in the future.At present,the channelization technology based on microwave photonics has broken the bandwidth bottleneck of electronic system and reduced the system bandwidth and sampling rate requirement.However,the DSP part of the system is still limited by traditional electronic devices,which is difficult to meet the demand of large bandwidth and high-speed data real-time processing.In this paper,a direct DFT scheme for wideband electromagnetic signals based on Dual Optical Frequency Comb(DOFC)combines the advantages of Optical large bandwidth and electronic narrow band fine control.The equivalent Fourier transform of broadband radio frequency signal is realized by physical devices.This solution only needs a low-speed analog-to-digital converter(ADC)to realize the real-time DFT calculation of broadband(10 GHz)signals.Using the system to capture the DFT coefficients of the radio frequency signal and simple mathematical calculations can capture all the spectrum information of the broadband electromagnetic signal and restore the original signal waveform with high fidelity.1)In this paper,two sets of DOFC direct Fourier transform systems--serial scanning and parallel detection systems are built.The performance of the system was tested on the DOFC direct Fourier transform serial scanning platform.2)The parallel detection capability of the system was initially verified on the DOFC Fourier transform parallel detection platform.3)The wireless communication function was developed on the DFT-based hardware system platform,which realized the successful demodulation of multiple modulation format signals such as binary phase shift keying(BPSK)and Orthogonal Frequency Division Multiplexing(OFDM),which proves that the system has great application potential in high-speed wireless signal reception.