Uniform modulated filterbank

A modulated filterbank is composed of analysis branches which:

• Modulate the input to center the desired sub-band at DC
• Lowpass filter the modulated signal to isolate the desired sub-band
• Downsample the lowpass signal

In $M$ -branch critically-sampled uniformly-modulated filterbanks, the $k$ th branch has a modulation frequency of $\pm ({\omega }_k)=\frac{2\pi }{M}k\mathrm{radians}$ , a lowpass cutoff frequency of $\frac{\pi }{M}$ radians, and a downsampling/upsampling factor of $M$ .

The most common way to implement this type of uniform modulated filterbank is through the use of polyphase filterbanks and DFTs .