10. A method of coding a signal at a predetermined bit rate, the signal reflecting speech information and comprising sets of signal segments, each set comprising a plurality of N signal segments, the method comprising the steps of: a. forming a plurality of trial coded representations of a set of N signal segments, each trial coded representation formed by 1. generating a coded representation of each of M signal segments of the set, which coded representation is generated based on output signals of a first speech coder and a second speech coder, where M is determined based on the predetermined bit rate; and 2. generating a coded representation of each of P other signal segments of the set, which coded representation is based on an output signal of the first speech coder; where P&gt;0 and M&gt;0 and N=P+M; and b. based on a coding criterion, selecting a particular trial coded representation to represent signal segments.
10. A method of coding a signal at a predetermined bit rate, the signal reflecting speech information and comprising sets of signal segments, each set comprising a plurality of N signal segments, the method comprising the steps of: a. forming a plurality of trial coded representations of a set of N signal segments, each trial coded representation formed by 1. generating a coded representation of each of M signal segments of the set, which coded representation is generated based on output signals of a first speech coder and a second speech coder, where M is determined based on the predetermined bit rate; and 2. generating a coded representation of each of P other signal segments of the set, which coded representation is based on an output signal of the first speech coder; where P&gt;0 and M&gt;0 and N=P+M; and b. based on a coding criterion, selecting a particular trial coded representation to represent signal segments. 13. The method of claim 10 wherein the step of generating a coded representation of each of P signal segments comprises, for each such segment, the steps of: a. generating a plurality of modified signal segments based on a signal segment to be coded; b. coding a modified signal segment to produce a modified signal segment coded representation; c. synthesizing an estimate of the modified signal segment based on the modified signal segment coded representation; d. determining an error between the signal segment to be coded and the synthesized estimate of the modified signal segment; and e. selecting as the coded representation of such signal segment to be coded a particular modified signal segment coded representation having an associated error which satisfies an error evaluation process.