polyscale() - Signal Processing
b = polyscale(a,alpha) scales
the roots of a polynomial in the z-plane, where a is a vector containing the polynomial
coefficients and alpha is the scaling factor.If alpha is a real value in the range [0 1], then the roots of a are
radially scaled toward the origin in the z-plane.
Complex values for alpha allow arbitrary changes
to the root locations.
b = polyscale(a,alpha)
Roots of UnityOpen This Example
Express the solutions to the equation
as the roots of a polynomial. Plot the roots in the complex plane.
pp = [1 0 0 0 0 0 0 -1];
Scale the roots of p in and out of the unit circle. Plot the results.hold on
for sc = [1:-0.2:0.2 1.2 1.4];
b = polyscale(pp,sc);
axis([-1 1 -1 1]*1.5)
Bandwidth Expansion of LPC Speech SpectrumOpen This ExampleLoad a speech signal sampled at
. The file contains a recording of a female voice saying the word "MATLAB®."load mtlb
Model a 100-sample section of the signal using a 12th-order autoregressive polynomial.Ao = lpc(mtlb(1000:1100),12);
Ax = polyscale(Ao,0.85);
Perform bandwidth expansion of the signal by scaling the roots of the autoregressive polynomial by 0.85. Plot the zeros, poles, and frequency responses of the models.subplot(2,2,1)
Output / Return Value
Alternatives / See Also