A Photonics Channelization Approach for Broadband RF Spectrum Measurement Based on I/Q Coherent Detection and Spectrum Stitching Technique

A novel channelization approach is proposed to realize a competitive photonics-based broadband RF spectrum measurement (BRSM) system with better completeness and cost-effectiveness based on a single OFC, I/Q coherent detection and improved FFT-based DSP. This photonics-based approach removes the need of complex tunable optical filters through optical direct conversion, and reduces the bandwidth requirement of hardware in each channel to half of the width of each spectrum slice. Relying on the coherence of the spectrum slices and the CE and spectrum stitching algorithm, a broadband and complex RF spectrum can be detected and reconstructed in a high fidelity. As a proof of concept, a two-channel architecture is analyzed in simulation to demonstrate the abilities in detecting and reconstructing the broadband RF spectrum. The operation bandwidth is up to 40GHz, and the analysis bandwidth per channel is <= 12.5GHz. The high degree of fidelity in the spectrum reconstruction are demonstrated with regression analysis of spectrum and coherence analysis of waveform between reconstructed signal and origin signal.