Patent ID: 6961698

Claim:
A communication system for transmitting a frame of a speech signal, the communication system comprising: a communication medium operable to transmit the frame in the form of a bitstream at a bit rate, the bit rate comprising one of a first bit rate of 8.5 kilobits per second and a second bit rate of 4.0 kilobits per second, the bitstream comprising: a type component representative of a type classification of the frame, the type classification comprising a first type and a second type; a gain component representing an adaptive codebook gain and a fixed codebook gain jointly encoded as a function of the bit rate when the type classification is the first type; the gain component comprising a fixed codebook gain component and an adaptive codebook gain component exclusively encoded as separate components of the bitstream as a function of the bit rate when the type classification is the second type; and a mode signal generation module in communication with the communication medium, the mode signal generation module operable to generate a mode signal indicative of a desired average bit rate for the bitstream.