An FFT-Based High SNR MWC Back-End Architecture with Analog Low-Pass Filter Compensation

We study the impacts of non-ideal filters in Modulated wideband converter (MWC). An analog filter compensating method is presented. The limitations of the conventional back-end of the advanced MWC is analyzed and an improved back-end based on Fast Fourier transform (FFT) is proposed. By setting proper length of the digital signal processed each time, the proposed system increases the recovery Signal-to-noise ratio (SNR) and significantly reduces the computation loads. The compensating operation is accurate to each frequency point and the expanding operation is simplified to a splitting of the frequency points. Numerical simulations demonstrate our proposed system against the ideal MWC with different filters. The results indicate that the recovery SNR of over 70 decibel is achieved with almost only one-tenth the computation complexity of the conventional MWC backend.