linear chirp signal generation ?
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Aniket
am 5 Feb. 2013
Kommentiert: Neal Bambha
am 16 Dez. 2019
hello i don't want to use chirp inbuilt function and i have written a code for chirp. could any one tell me is the code is correct ? i have simulate it and getting plot but at instantaneous time t1, I am not getting frequency change.
i have written a code according to equation of chirp signal generation.
please tell me this is correct ?
*****************************************
f1 =10;
f2 = 50 ;
t =0:0.001:20;
t1 = 10;
alpha = (f2-f1)/t1;
f= (alpha)*t + f1;
xx =1*cos(f);
plot (t,xx);
**********************************************
1 Kommentar
Neal Bambha
am 16 Dez. 2019
This is not the correct expression for a linear chirped signal. See the wikipedia page for "Chirp" There is a t-squared term in the sine. Otherwise you will not have the correct spectrum
chirp_slope = (f2 - f1)/t(end);
chirp_signal = sin(2*pi*(0.5*chirp_slope*t.^2 + f1*t));
Akzeptierte Antwort
Youssef Khmou
am 5 Feb. 2013
Bearbeitet: Youssef Khmou
am 5 Feb. 2013
hi, try this :
Fs=1000; % sample rate
tf=2; % 2 seconds
t=0:1/Fs:tf-1/Fs;
f1=100;
f2=400; % start @ 100 Hz, go up to 400Hz
semi_t=0:1/Fs:(tf/2-1/Fs);
sl=2*(f2-f1/2);
f1=f1*semi_t+(sl.*semi_t/2);
f2=f1(end)+f2*semi_t-sl.*semi_t/2;
f=[f1 f2];
y=1.33*cos(2*pi*f.*t);
plot(t,y)
To check the Amplitude spectrum (100Hz,400Hz), try my submission : http://www.mathworks.com/matlabcentral/fileexchange/40002-psd-power-spectral-density-and-amplitude-spectrum-with-adjusted-fft
6 Kommentare
Atilla Golan
am 21 Jan. 2018
Bearbeitet: Atilla Golan
am 21 Jan. 2018
Hi Youssef, Can we try up-going and down going chirp together? (without using chirp function on Matlab). In a time range of [1.2s 2.7s] (for example) my function should go up 0.6s (since 1.2s to 1.8s) and go down for the rest (since 1.8s to the end:2.7s). I mean in a constant frequency range, function goes up and down during time like quadratic chirp function but without using chirp.
Dhananjay Singh
am 25 Feb. 2019
hi youssef,
the code you last sent doesn't work when i set the values of f1, f2 in Khz. can you help?
Weitere Antworten (3)
REEM ALI
am 30 Jan. 2014
please i want to generate triangular modulation sweep of fmcw of rx and tx
0 Kommentare
farouk behar
am 11 Aug. 2015
f = 150; a =5; w =2*pi*f; t =0:0.1:20; theta = pi/2; X = a*cos((w*t)+theta); y0 = X + 2*rand(size(t));
plot(t,y0)
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