Parabolic frequency modulated signal
[X,IFLAW] = fmpar(N, P1) [X,IFLAW] = fmpar(N, P1, P2) [X,IFLAW] = fmpar(N, P1, P2, P3)
a positive integer: number of points in time
a real vector of size 2 or 3
if the number of input arguments is 2, P1 is a vector containing the three coefficients [A0 A1 A2] of the polynomial instantaneous phase.
if the number of input arguments is 3, P1 is a time-frequency point of the form [t,f]. where t is in seconds and f is a normalized frequency (between 0 and 0.5).
a real 2 elements vector:
P2 is a time-frequency point of the form [t,f]. where t is in seconds and f is a normalized frequency (between 0 and 0.5).
a real 2 elements vector:
P3 is a time-frequency point of the form [t,f]. where t is in seconds and f is a normalized frequency (between 0 and 0.5).
real column vector: the modulated signal time samples. Sampling frequency is set to 1.
real column vector: instantaneous frequency law
fmpar generates a signal with parabolic frequency modulation law. X(T) = exp(j*2*pi(A0.T + A1/2.T^2 +A2/3.T^3)). When called with 4 input arguments F0 and C are derived from P1, P2 and P3 such that the frequency modulation law fits the points P1, P2 and P3.
[X1,IFLAW1] = fmpar(128,[1 0.4],[64 0.05],[128 0.4]); [X2,IFLAW2] = fmpar(128,[0.4 -0.0112 8.6806e-05]); subplot(211); plot(real(X1),"b"); plot(real(X2),"r") subplot(212); plot(IFLAW1,"b"); plot(real(IFLAW2),"r") | ![]() | ![]() |