Audio encoding device, audio decoding device, and their method

A speech decoding apparatus comprising:

• a first decoding section that decodes first encoded data and acquires a first decoded signal comprising a lower band of a speech signal;
• a pitch filter that has a multitap configuration comprising a filter parameter for smoothing a harmonic structure;
• and
• a second decoding section that sets a filter state of the pitch filter based on a spectrum of the first decoded signal and acquires a second decoded signal which is a higher band of the speech signal by decoding second encoded data using the pitch filter.

A speech coding method comprising the steps of:

• encoding a lower band of an input signal and generating first encoded data;
• decoding the first encoded data and generating a first decoded signal;
• setting a filter state of a pitch filter that has a multi-tap configuration comprising a filter parameter for smoothing a harmonic structure, based on a spectrum of the first decoded signal;
• and
• generating second encoded data by encoding a higher band of the input signal using the pitch filter.

A speech decoding method comprising:

• decoding a first encoded data and acquiring a first decoded signal comprising a lower band of a speech signal;
• setting a pitch filter that has a multitap configuration comprising a filter parameter for smoothing a harmonic structure, based on a spectrum of the first decoded signal;
• and
• acquiring a second decoded signal comprising a higher band of the speech signal by decoding second encoded data using the pitch filter.