Practical consideration for a continuous time digital spectrum analyzer

The authors propose a paradigm shift for digital spectrum analysis from a transform to a digital filter bank. With the digital filter bank, they gain an additional degree of freedom in the design of the windows, namely, the window length can be specified independently of the DFT length. The authors also explain the problem of measurement aliasing when more than one component fall within the passband of a DFT bin. With this digital filter bank point of view, they design a flat-top window with very sharp roll-off, achieving excellent frequency resolution