1 hour ago · It completely describes the discrete-time Fourier transform (DTFT) of an -periodic sequence, which comprises only discrete frequency components. (Using the DTFT with periodic data)It can also provide uniformly spaced samples of the continuous DTFT of a finite length sequence. (§ Sampling the DTFT)It is the cross correlation of the input sequence, , and a complex sinusoid at frequency .
A set of elements in the periodic table of elements, defined by shape of an orbital—s, p, d, or f—where the valence electron lies
A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in. The term seems to have been first used by Charles Janet. Each block is named after its characteristic orbital: s-block, p-block, d-block, f-block and g-block. The block names (s, p, d, and f) are derived from the spectroscopic notation for the value of an electron's azimut... Wikipedia
