Regeneration of wideband speed

A method of regenerating a wideband speech signal at a receiver which receives a narrowband speech signal in encoded form via a transmission channel, the method comprising:

• decoding the received signal to generate speech samples of a narrowband speech signal;
• regenerating from the narrowband speech signal a highband speech signal, the highband speech signal having a range of frequencies above that of the narrowband speech signal;
• determining a pitch of the high hand speech signal;
• using the pitch to generate a pitch-dependent tonality measure from samples of the highband speech signal;
• filtering the speech samples using a gain factor derived from the tonality measure and selected to reduce the amplitude of harmonics in the highband speech signal;
• and
• combining the filtered highband speech signal with the narrowband speech signal to regenerate the wideband speech signal.

A system for processing a narrowband speech signal comprising speech samples in a first range of frequencies, the system comprising:

• means for generating from the narrowband speech signal a highband speech signal in a second range of frequencies above the first range of frequencies;
• means for determining a pitch of the highband speech signal;
• means for generating a pitch-dependent tonality measure from samples of the highband speech signal using the pitch;
• and
• means for filtering the speech samples using a gain factor derived from the tonality measure and selected to reduce the amplitude of harmonics in the highband speech signal.