Fujisaki Model

The Fujisaki model is a superpositional model for representing F₀ contour of speech. According to the model, F₀ contour is generated as a result of the superposition of the outputs of two second order linear filters with a base frequency value. The second order linear filters are for generating the phrase and accent components of speech. The base frequency is the minimum frequency value of the speaker.
In other words, F₀ contour is obtained by adding base frequency, phrase components and accent components. This model was proposed by Hiroya Fujisaki.

F 0 ( t ) = l n ( F b ) + ∑ i = 1 I A p i G p ( t − T 0 i ) + ∑ j = 1 J A a j { G a ( t − T 1 j ) − G a ( t − T 2 j ) }
where
G p ( t ) = α 2 t e x p ( − α t ) f o r   t ≥ 0
G a ( t ) = m i n [ 1 − ( 1 + β t ) e x p ( − β t ) , γ ] f o r   t ≥ 0