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5 Methods for Discrete Processing and Analysis of Biosignals

Fig. 5.10: Spectrum of a discrete-time signal at triple oversampling by adding two additional values

between each two samples but equal to zero, see Figure 5.9.

shift j

shift j

oversampling

with factor 3

anti-image

lowpass

LP

Fig. 5.11: Interpolation example of a discrete-time signal using the insertion of two zeros between

each two samples followed by low-pass filtering.

After successful suppression of these "interfering parts" in the spectrum by a low-

pass filter (see Figure 5.11), one then obtains new additional samples that inter-

polate the signal in the same way as if it had previously been converted into a