Patent ID: 8184922

Claim:
A digital filter configuration for the filtration of a digital video signal, wherein the functions of a zoom filter, in the form of a low-pass filter, which is a polyphase filter, and of at least one peaking filter, in the form of a high-pass filter, are realized, wherein the functions of the two filters are realized in a combined filter in an integrated circuit in a manner such that, for each phase of the zoom filter to be set, combined filter coefficients are calculated in real time according to a summation formula in conjunction with implementation of the filtration of the digital video signal, wherein the combined filter coefficients are calculated from filter coefficients stored for a corresponding phase of the zoom filter and from filter coefficients stored for the peaking filter, wherein each combined filter coefficient comprises a single value derived from a combination of at least one of the filter coefficients stored for the corresponding phase of the zoom filter and at least one of the filter coefficients stored for the peaking filter, which combined filter coefficients are applied to the video data to be filtered in a filtration process, so that both filtration functions are executed with the combined filter coefficients in this filtration process, and further wherein the calculation of the filter coefficients of the combined filter is undertaken in accordance with: Coefficient k = ∑ z = 0 y - 1 ⁢ ⁢ F 2 ⁢ ( y - z ) * F 1 ⁢ ( k - y + 1 + z ) where F 1 =Coefficients of a phase of the zoom filter, x=Quantity of the coefficients F 1 of a phase of the zoom filter, F 2 =Coefficients of the peaking filter, y=Quantity of the coefficients F 2 of the peaking filter, n=Quantity of the coefficients of the combined filter, k=Consecutive number of the coefficient to be calculated (1, 2 . . . n) of the combined filter, wherein: n=x+y−1.