Patent ID: 7725311

Claim:
A conversion entity for converting higher-rate speech parameters for a current frame into lower-rate speech parameters for the current frame, the conversion entity comprising: a first decoder configured to produce a respective target excitation signal for each of a series of frames including the current frame and a previous frame, the target excitation signal for a given frame being based on a respective first fixed contribution for the given frame and a respective first adaptive contribution for the given frame; a second decoder configured to produce a second adaptive contribution for the current frame and further configured to selectably operate in a first mode or a second mode; in the first mode, the second adaptive contribution for the current frame being generated based on the first fixed contribution for the previous frame; in the second mode, the second adaptive contribution for the current frame being generated based on a second fixed contribution for the previous frame; the second decoder being configured to operate in the second mode in response to a rate reduction request for the current frame; a processing module configured to determine dimmed excitation parameters for the current frame, the dimmed excitation parameters for the current frame being generated based on the target excitation signal for the current frame and the second adaptive contribution for the current frame, the dimmed excitation parameters for the current frame being used to generate a second fixed contribution for the current frame; wherein the dimmed excitation parameters for the current frame are included in the lower-rate speech parameters for the current frame.