Speech coding with improved background noise reproduction

speech decoding apparatus, comprising:

• an input for receiving encoded information from which an approximation of an original speech signal is to be produced;
• an output for outputting said approximation;
• a parameter determiner coupled to said input for determining from the encoded information a current parameter to be used in producing an approximation of a current segment of the original speech signal;
• a reconstructor coupled between said parameter determiner and said output for producing the approximation of the original speech signal;
• a modifier coupled between said parameter determiner and said reconstructor for using said current parameter and corresponding previous parameters respectively associated with previous segments of the original speech signal to produce a modified parameter, said modifier includes a mix factor determiner for determining a mix factor indicative of the importance of the previous parameters relative to the current parameter in producing the modified parameter;
• and
• said modifier further for providing said modified parameter to said reconstructor for use in producing said approximation of the current segment of the original speech signal.

A transceiver apparatus for use in a communication system, comprising:

• an input for receiving information from a transmitter via a communication channel;
• an output for providing an output to a user of the transceiver;
• a speech decoding apparatus having an input coupled to said transceiver input and having an output coupled to said transceiver output, said input of said speech decoding apparatus for receiving from said transceiver input encoded information from which an approximation of an original speech signal is to be produced, said output of said speech decoding apparatus for providing said approximation to said transceiver output;
• and
• said speech decoding apparatus further including a parameter determiner coupled to said input of said speech decoding apparatus for determining from said encoded information current parameters to be used in producing an approximation of a current segment of the original speech signal, a reconstructor coupled between said parameter detector and said output of said speech decoding apparatus for producing the approximation of the original speech signal, and a modifier coupled between said parameter detector and said reconstructor for using at least one of the current parameters and corresponding previous parameters respectively associated with previous segments of the original speech signal to produce a modified parameter, said modifier includes a mix factor determiner for determining a mix factor indicative of the importance of the previous parameters relative to the current parameter in producing the modified parameter, said modifier further providing the modified parameter to the reconstructor for use in producing said approximation of the current segment of the original speech signal.