Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Downsampling Non-Uniformly Sampled Data | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 147407 10 pages doi 2008 147407 Research Article Downsampling Non-Uniformly Sampled Data Frida Eng and Fredrik Gustafsson Department of Electrical Engineering Linkopings Universitet 58183 Linkoping Sweden Correspondence should be addressed to Fredrik Gustafsson fredrik@ Received 14 February 2007 Accepted 17 July 2007 Recommended by . Li Decimating a uniformly sampled signal a factor D involves low-pass antialias filtering with normalized cutoff frequency 1 D followed by picking out every Dth sample. Alternatively decimation can be done in the frequency domain using the fast Fourier transform FFT algorithm after zero-padding the signal and truncating the FFT. We outline three approaches to decimate non-uniformly sampled signals which are all based on interpolation. The interpolation is done in different domains and the intersample behavior does not need to be known. The first one interpolates the signal to a uniformly sampling after which standard decimation can be applied. The second one interpolates a continuous-time convolution integral that implements the antialias filter after which every Dth sample can be picked out. The third frequency domain approach computes an approximate Fourier transform after which truncation and IFFT give the desired result. Simulations indicate that the second approach is particularly useful. A thorough analysis is therefore performed for this case using the assumption that the non-uniformly distributed sampling instants are generated by a stochastic process. Copyright 2008 F. Eng and F. Gustafsson. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Downsampling is here considered for a non-uniformly sampled signal. Non-uniform sampling .
