linear chirp signal generation ?
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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);
**********************************************
댓글 수: 1
Neal Bambha
2019년 12월 16일
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));
채택된 답변
Youssef Khmou
2013년 2월 5일
편집: Youssef Khmou
2013년 2월 5일
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
댓글 수: 6
Atilla Golan
2018년 1월 21일
편집: Atilla Golan
2018년 1월 21일
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
2019년 2월 25일
hi youssef,
the code you last sent doesn't work when i set the values of f1, f2 in Khz. can you help?
추가 답변 (3개)
REEM ALI
2014년 1월 30일
please i want to generate triangular modulation sweep of fmcw of rx and tx
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farouk behar
2015년 8월 11일
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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