Event Detection: Qrs-Complexes in Ecg Signals - microLab

BioMedSigProcAnademand on preservation of signal forms calls for linear-phasefilters, which must be Fir filters. “Integer” filters as we discussthem here are Fir filters with recursive implementations.The slide on the previous page 14 states that our “integer”filters have only coefficients being 0, ±1, and ±2. This is notthe full truth: The basic blocks that we consider have suchcoefficients, but cascading these basic blocks leads to additionalcoefficient values, see page 27.Simple Example• transfer function• zerosH(z) =N(z z ) = z 6 z − 1 ≡ 01 − z −61 − z −1 + z −2 = z 6 − 1z 4 (z 2 − z + 1)ˆ=N(z)D(z)❀z z = e j·k·2π/6 , k = 0, 1, . . ., 5 ˆ= 6-th roots of unity❝j❝❝.❝1❝❝zeros: 6-th roots of unityNote that the transfer function of the above example definesa filter that has only coefficients ±1.6 EventDet 15 2014