TY - JOUR
N2 - In this paper, we show that signal sampling operation can be considered as a kind of all-pass filtering in the time domain, when the Nyquist frequency is larger or equal to the maximal frequency in the spectrum of a signal sampled. We demonstrate that this seemingly obvious observation has wideranging implications. They are discussed here in detail. Furthermore, we discuss also signal shaping effects that occur in the case of signal under-sampling. That is, when the Nyquist frequency is smaller than the maximal frequency in the spectrum of a signal sampled. Further, we explain the mechanism of a specific signal distortion that arises under these circumstances. We call it the signal shaping, not the signal aliasing, because of many reasons discussed throughout this paper. Mainly however because of the fact that the operation behind it, called also the signal shaping here, is not a filtering in a usual sense. And, it is shown that this kind of shaping depends upon the sampling phase. Furthermore, formulated in other words, this operation can be viewed as a one which shapes the signal and performs the low-pass filtering of it at the same time. Also, an interesting relation connecting the Fourier transform of a signal filtered with the use of an ideal low-pass filter having the cut frequency lying in the region of under-sampling with the Fourier transforms of its two under-sampled versions is derived. This relation is presented in the time domain, too.
L1 - http://journals.pan.pl/Content/117111/PDF/80_2532_Borys_skl_new.pdf
L2 - http://journals.pan.pl/Content/117111
PY - 2020
IS - No 3
EP - 594
DO - 10.24425/ijet.2020.134016
KW - Signal sampling
KW - filtering
KW - discrete-time Fourier transform
A1 - Borys, Andrzej
PB - Polish Academy of Sciences Committee of Electronics and Telecommunications
VL - vol. 66
T1 - Filtering Property of Signal Sampling in General and Under-Sampling as a Specific Operation of Filtering Connected with Signal Shaping at the Same Time
DA - 2020.09.17
SP - 589
UR - http://journals.pan.pl/dlibra/publication/edition/117111
T2 - International Journal of Electronics and Telecommunications
ER -