31 results about "Bandwidth expansion" patented technology

Bandwidth expansion is a technique for widening the bandwidth or the resonances in an LPC filter. This is done by moving all the poles towards the origin by a constant factor γ. The bandwidth-expanded filter Aʼ(z) can be easily derived from the original filter A(z) by: Aʼ(z)=A(z/γ) Let A(z) be expressed as: A(z)=∑ₖ₌₀ᴺaₖz⁻ᵏ The bandwidth-expanded filter can be expressed as: Aʼ(z)=∑ₖ₌₀ᴺaₖγᵏz⁻ᵏ In other words, each coefficient aₖ in the original filter is simply multiplied by γᵏ in the bandwidth-expanded filter.