Design and Simulation of a Hybrid Filter Bank for Processing Wideband Signals with Low-Speed ADCs

Abstract

Currently, there is a tendency to increase the speed of information transmission by increasing used frequency band. However, when switching to broadband signals and operating under conditions of a high level of noise, a wide dynamic range is required when digitizing the received signal. To increase the dynamic range, it is proposed to use a hybrid filter bank, which allows processing the broadband signal with low-speed precision analog-to-digital converters. In this paper, was calculated and simulated a hybrid analysis-synthesis filter bank for the 26.25 MHz-86.25 MHz frequency range. Using matched filters, we estimated the distortion of a linearly frequency-modulated signal during the passage of filter banks without intermediate processing, after upsampling and downsampling intermediate signals from the outputs of analog filters. To reduce phase shifts and time delays arising during signal processing by synthesis filters, compensation delays and phase shifts were introduced, adjusted to distortions carried by the processing system. It was shown that phase correction allows reducing signal distortions. It was also shown that in the case of receiving a mixture of signal and noise, the distortion introduced by the processing system does not significantly affect the signal-to-noise ratio of the output signal.