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fmpar

Parabolic frequency modulated signal

Calling Sequence

[X,IFLAW] = fmpar(N, P1)
[X,IFLAW] = fmpar(N, P1, P2)
[X,IFLAW] = fmpar(N, P1, P2, P3)

Parameters

N :

a positive integer: number of points in time

P1 :

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).

P2 :

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).

P3 :

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).

X :

real column vector: the modulated signal time samples. Sampling frequency is set to 1.

IFLAW :

real column vector: instantaneous frequency law

Description

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.

Examples

[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")

See also

Authors


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