Error concealment or correction of speech, image and video signals

A method of error concealment or correction of a sampled analog signal comprising:

• receiving a signal in which some samples have not been correctly received;
• and
• recovering a signal from the received signal by using redundancy introduced into the transmitted signal, said redundancy consisting of a predetermined set of M Fourier components in each block of the discrete Fourier transform of the transmitted signal of block length N being equal to zero;
• CHARACTERISED IN THAT
• said predetermined set of Fourier coefficients consists of the coefficients numbered p(k) where k takes on M successive integer values, p(k) being defined as p(k)=pk mod N where p is a positive integer, greater than unity, relatively prime to N.

An apparatus for introducing increased redundancy into a discrete signal for the purpose of error concealment or correction of bursty and/or frame losses comprising:

• means for forming the discrete Fourier transform of a block of samples of said signal;
• means for modifying said Fourier transform to form a block of coefficients of block length N in which a predetermined set of M Fourier coefficients are equal to zero;
• and
• means for forming the inverse discrete Fourier transform of said block of Fourier coefficients to form the increased-redundancy signal;
• CHARACTERISED IN THAT
• said predetermined set of Fourier coefficients consists of the coefficients numbered p(k) where k takes on M successive integer values, p(k) being defined as p(k)=pk mod N where p is a positive integer, greater than unity, relatively prime to N.

An apparatus for error concealment or correction of a sampled analog signal comprising:

• means for receiving a signal in which some samples have not been correctly received;
• and
• means for recovering a signal from the received signal by using redundancy introduced into the transmitted signal, said redundancy consisting of a predetermined set of M Fourier components in each block of the discrete Fourier transform of the transmitted signal of block length N being equal to zero;
• CHARACTERISED IN THAT
• said predetermined set of Fourier coefficients consists of the coefficients numbered p(k) where k takes on M successive integer values, p(k) being defined as p(k)=pk mod N where p is a positive integer, greater than unity, relatively prime to N.