7. The method of claim 3 , wherein: the vector is a line spectral frequency (LSF) vector including line spectral frequencies (LSFs); the illegal space represents illegal LSF vectors; and each candidate codevector is an LSF vector.
3. The method of claim 1 , wherein step (a) comprises: (a)(i) determining whether each candidate codevector among the set of candidate codevectors corresponds to an illegal space that represents illegal vectors, wherein the illegal space is defined by the one or more illegal space definitions; and (a)(ii) declaring as a legal candidate codevector each candidate codevector that does not correspond to the illegal space.