This paper introduces the generalized sharpening technique to improve the magnitude characteristics of comb decimation filter in passband as well in the folding bands. To this end we design two-stage comb filter. The first stage can be operated at low sampling rate by using polyphase decomposition. A simple compensator is applied in the second stage to improve the passband characteristic of the comb in the second stage. Then the generalized sharpening technique is applied to decrease the passband droop induced by the comb filter placed in the first stage. As a result, a computationally efficient comb-based decimation filter is obtained which presents better magnitude characteristics than previous proposed sharpening methods.