Transmitter, receiver and a method for digital multiple sub-band processing

A transmitter that comprises:

• a set of first filters with outputs connected to a summing node;
• a set of upsamplers;
• a set of sub-band processors, wherein each sub-band processor comprises an interpolator, a cyclic shifter and a second filter;
• wherein each cyclic shifter is coupled between an interpolator and an upsampler;
• wherein each first filter follows an upsampler;
• wherein different interpolators are arranged to receive different sets of signals and perform up-sampling;
• wherein the set of first filters is arranged to output virtual sub-channels of information occupying disjoint spectral sub-bands;
• wherein each sub-band is associated with a pair of filters that comprises a first filter and a second filter, wherein the first filter has a milder frequency response outside the sub-band than a frequency response of the second filter outside the sub-band.