input module 2 c includes two parallel connected switches 32 each having an assigned low pass filter 34 the integral of signal x t is formed at various instances in conformance with the corresponding haar wavelet function see equation 14 with the assistance of the function of switches 32 and of low pass filters 34 in each branch 20 both results of input module 2 c are subsequently summed in a summing unit 36 in this context each result of input module 2 c characterizes a half wave of the corresponding haar wavelet function thus each branch 20 processes a haar wavelet function the various wavelet functions being generated by doubling or halving the width and by shifting the width by integral multiples coefficient a j of the wavelet transformation is subsequently supplied for digitization to corresponding module 6 to normalize discrete coefficient a j d as a function of the corresponding wavelet function a matching element 38 is provided in corresponding branch 20 thus the normalization is carried out in the digital domain for purposes of inverse transformation output module 4 includes multiplier 22 the normalized coefficients c i j in the digital domain determined with the assistance of the matching element are supplied to multiplier 22 for purposes of inverse transformation see equation 12 where c i j l u03c8 x a 1 b i through subsequent.