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: http://www.mrao.cam.ac.uk/~rachael/systems/Summary2.html
Äàòà èçìåíåíèÿ: Tue Feb 10 15:01:56 2004 Äàòà èíäåêñèðîâàíèÿ: Tue Oct 2 04:55:00 2012 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: massive stars |
1. Sampling is multiplication by a comb of delta functions:
á á
2. Fourier transformá á á
á á
3. Alternative representation of FT:
á á
á á á á á á á á possibility of aliasing.
4. Finite length sequence á convolution with sinc function.
5. Windowingá á multiply sequence in order to achieve balance between width and sidelobes of convolving function
6. Leakage á sidelobes of window function may affect appearance of samples in the frequency domain.
7. Circular convolution á sampling the function in the frequency domain á á periodicity in the time domain.
8. Filtering of sampled data in frequency domain is convolution in the time domain over a periodic function.
9. Stability determined as for continuous systems: stable if no poles in Right Half-Plane.