Multi-window fast convolution processing

According to an aspect, there is provided a waveform processing device (600). Said waveform processing device (600) comprises means for performing the following. Upon receiving one or more input signals (601, 611, 621), each of which corresponds to a different subband, the waveform processing device (600) segments each of the one or more input signals (600, 611, 621) to a subband-specific set of parallel signal blocks. Then, the waveform processing device (600) filters each subband-specific set by applying at least a first time window function (603, 613, 623), a transform-plane window function (604, 614, 624) and a second time window function (608) in this order. Finally, the waveform processing device (600) concatenates filtered signals to an output signal (610).