qinterp

Compute interploated coordinates of local peaks of a function using 2nd order interpolation.

Usage

qinterp(dxscalar, y, ip {, nwidth})

qinterp(xvector, y, ip {, nwidth})

dx

distance bewteen x values; x[i] = dx * i

x

x data vector

y

y data vector; y[i] = f(x[i]).

ip

a scalar or vector containing the indices of local maxima

nwidth

the width to be used for interpolation

Result

A vector r with 2 elements (r[0] = xpeak, r[1] = ypeak) or a matrix with two rows (r[0,j] = xpeak_j, r[1,j] = ypeak_j) containing the interpolated coordinates of the local maxima (peaks). For the 2nd order (parabolic) interpolation the (x,y) points at ip-npeaks, ip and ip+npeask are used.

See also

ipeak, formants

<function list>

qinterp

Lays a parabola through three points around each peak value and calculates the interpolated peak. The result is a one or two row vector or matrix.

Usage:

qinterp(x, y, ipeak, nwidth)

Parameters:

x

The number for x[i] = i*number or the x-scale vector.

y

The data vector (function).

ipeak

The indices of the peak values or the center of the interpolation.

nwidth

The width of the interpolation. The default is 1.

Return Type:

vector or matrix

Result:

row 1 = xpeak[]

row 2 = ypeak[]