The impulse responses hk(n) of the filters in a T-channel cosine modulated filter bank may be written h k ( n ) = C p 0 ( n ) cos [ ??? 2 T ( 2 k + 1 ) ( n - N - 1 2 ) + ?? k ] , ( 19 ) where k=0, 1, . . . , T???1, N is the length of the lowpass prototype filter p0(n), C is a constant and ??k is a phase-angle that ensures alias cancellation between adjacent channels.