Patent ID: 8594343

Claim:
A sound processing apparatus installed in an audio apparatus and having a circuit configuration configured to interpolate positions among a plurality of temporally-ordered discrete data input in series at given time intervals, the sound processing apparatus comprising: a discrete data extraction unit configured to extract said discrete data in series to hold; and a function processing unit configured to receive at a time a given number of said discrete data extracted to be held by said discrete data extraction unit and to perform an interpolation process using said discrete data, wherein said function processing unit is configured to calculate interpolation values among discrete data, by using a fundamental term calculation unit configured to perform a convolution operation using a fundamental sampling function applied to said discrete data, a control term calculation unit configured to perform a convolution operation using a control sampling function applied to said discrete data and a linear adding unit configured to linearly add the calculated results obtained by each of said convolution operations, wherein a sampling function used in said function processing unit consists of said fundamental sampling function which is finitely differentiable and has a value of finite support and of a said control sampling function which is finitely differentiable and has a value of finite support and further exhibits a waveform different from a waveform exhibited by the fundamental sampling function, wherein said function processing unit includes a coefficient multiplication unit configured to multiply a value of the calculated result of said convolution operation using said control sampling function by a variable parameter settable as an arbitrary value by a user, and wherein when a sampling position of said discrete data is defined as t and said fundamental sampling function is defined as f(t), said fundamental sampling function is expressed by the following formula 20, f ⁡ ( t ) = { 0 t ∈ ( - ∞ , - 1 ) 2 ⁢ ( t + 1 ) 2 t ∈ [ - 1 , - 1 2 ) - 2 ⁢ t 2 + 1 t ∈ [ - 1 2 , 1 2 ) 2 ⁢ ( - t + 1 ) 2 t ∈ [ 1 2 , 1 ) 0 t ∈ [ 1 , ∞ ) , [ Formula ⁢ ⁢ 20 ] when said control sampling function is set as C0(t)=Cr(t)+Cr (−t), said Cr(t) is expressed by the following formula 21, c r ⁡ ( t ) = { 0 t ∈ ( - ∞ , 0 ) - t 2 t ∈ [ 0 , 1 2 ) 3 ⁢ ( - t + 1 ) 2 - 2 ⁢ ( - t + 1 ) t ∈ [ 1 2 , 1 ) - 3 ⁢ ( t - 1 ) 2 + 2 ⁢ ( t - 1 ) t ∈ [ 1 , 3 2 ) ( - t + 2 ) 2 t ∈ [ 3 2 , 2 ) 0 t ∈ [ 2 , ∞ ) [ Formula ⁢ ⁢ 21 ] and the sampling function is expressed by the following formula 22, s 2 ⁡ ( t ) = f ⁡ ( t ) + α · c 0 ⁡ ( t ) [ Formula ⁢ ⁢ 22 ] wherein said variable parameter settable as an arbitrary value by a user is defined as a and the sampling function between sampling position [−2, 2] of the discrete data is defined as s 2 (t).