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dopnoise

Complex noisy doppler signal

Calling Sequence

[Y,IFLAW] = dopnoise(N, FS, F0, D, V, T0, C)

Parameters

N :

a positive integer: the number of points.

FS :

a positive scalar : the sampling frequency (in Hertz).

F0 :

a scalar in ]0 FS/2]: the target frequency (in Hertz).

D :

a positive scalar: the distance from the line to the observer (in meters).

V :

a positive scalar: the target velocity (in m/s).

T0 :

a positive integer in [1 N]: the time center index (default : round(N/2)).

C :

a positive scalar: the wave velocity (in m/s) (default : 340).

Y :

Output signal.

IFLAW :

Model used as instantaneous frequency law.

Description

dopnoise generates a complex noisy doppler signal, normalized so as to be of unit energy.

Examples

rand("seed",0)
[z,iflaw] = dopnoise(500,200,60,10,70,128);
clf
subplot(211); plot(real(z)); xtitle(_("Signal real part"))
subplot(212); plot(iflaw);
ifl = instfreq(z,11:478,10);
plot(ifl,'g');

xtitle(_("Instantaneous frequency"))
legend([_("Requested"),_("Obtained")]);

sum(abs(z).^2) // check energy

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<< chirp Choice of Particular Signals doppler >>