RECONSTRUCTION OF NONUNIFORMLY SAMPLED BANDLIMITED SIGNALS

摘要

The present invention refers to a method and apparatus for reconstruction of a nonuniformly sampled bandlimited analog signal xa(t), said nonuniformly sampled signal comprising N subsequences xk(m), k=0, 1, . . . , N-1, N=2, obtained through sampling at a sampling rate of 1/(MT) according to xk(m)=xa(nMT+tk), where M is an integer, and tk=kMT/N+DELTAtk, DELTAtk being different from zero. The invention comprises forming a new sequence y(n) from said N subsequences xk(m) such that y(n) at least contains the same information as x(n)=xa(nT), i.e. xa(t) sampled with a sampling rate of 1/T, in a frequency region lower than omega0, omega0 being a predetermined limit frequency, by means of (i) upsampling each of said N subsequences xk(m), k=0, 1, . . . , N-1, by a factor M, M being a positive integer; (ii) filtering each of said upsampled N subsequences xk(m), k=0, 1, . . . , N-1, by a respective digital filter; and (iii) adding said N digitally filtered subsequences to form y(n). The respective digital filter is preferably a fractional delay filter and has preferably a frequency response Gk=ake(-jomegasT), k=0, 1, . . . , N-1, in the frequency band |omegaT|=omega0T, ak being a constant and s=d+tk, d being an integer.