fmpar

Purpose

Signal with parabolic frequency modulation.

Synopsis

[x,iflaw] = fmpar(N,P1)
[x,iflaw] = fmpar(N,P1,P2,P3)

Description

fmpar generates a signal with parabolic frequency modulation law :

$$x(t) = \exp(j2\pi(a_0 t + \frac{a_1}{2} t^2 +\frac{a_2}{3} t^3)).$$

Name	Description	Default value
N	number of points in time
P1	if nargin=2, P1 is a vector containing the three coefficients (a0 a1 a2) of the polynomial instantaneous phase. If nargin=4, P1 (as P2 and P3) is a time-frequency point of the form (ti fi). The coefficients (a0,a1,a2) are then deduced such that the frequency modulation law fits these three points
P2, P3	same as P1 if nargin=4.	optional
x	time row vector containing the modulated signal samples
iflaw	instantaneous frequency law

Examples

         [x,iflaw]=fmpar(200,[1 0.4],[100 0.05],[200 0.4]);
         subplot(211);plot(real(x));subplot(212);plot(iflaw);
         [x,iflaw]=fmpar(100,[0.4 -0.0112 8.6806e-05]);
         subplot(211);plot(real(x));subplot(212);plot(iflaw);

See Also

fmconst, fmhyp, fmlin, fmsin, fmodany, fmpower.

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