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Time Frequency Toolbox >> Time Frequency Toolbox > Choice of the Instantaneous Frequency > fmpar

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 :

the 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

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))

Examples

[X,IFLAW]=fmpar(128,[1 0.4],[64 0.05],[128 0.4]);
subplot(211);plot(real(X));subplot(212);plot(IFLAW);
[X,IFLAW]=fmpar(128,[0.4 -0.0112 8.6806e-05]);
subplot(211);plot(real(X));subplot(212);plot(IFLAW);

See also

Authors

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