Empirical determination of the frequencies of an almost periodic sequence

This note is concerned with the problem of determination of the countable set /spl Lambda/={/spl lambda//sub 1/, /spl lambda//sub 2/, ...} of frequencies belonging to an almost periodic sequence by methods in which a finite number of frequencies {/spl lambda//sub 1//sup (n)/, /spl lambda//sub 2//sup (n)/, ..., L(K/sub n/)/sup (n)/}=/spl Lambda//sub n/ are produced at each stage n. We seek algorithms for which /spl Lambda//sub n/ converges to /spl Lambda/ but yet each /spl Lambda//sub n/ is not too big.