Sine wave changing amplitude
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Can you have a sine wave with varying amplitudes? I think this concept does not exist.
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Antworten (3)
Image Analyst
am 6 Nov. 2014
See attached demo (make_wav_file.m, below the plot) where I vary the amplitude and frequency of a sound wave.
2 Kommentare
Tahariet Sharon
am 27 Okt. 2017
Bearbeitet: Tahariet Sharon
am 27 Okt. 2017
Yes, but the initial qustion was about changing the amplitude of a SINE wave, not a complex wave.
Image Analyst
am 27 Okt. 2017
My demo DOES modify the amplitude of a sine wave. Perhaps you overlooked this line of code in it:
% Construct the waveform:
y = int16(Amplitude .* sin(2.*pi.*t./T));
The amplitude array is changing according to 2 ways in my demo: an exponential decay and another lower frequency since wave, but you could alter the amplitude in whatever way you want. So I'm not sure why the "but" is in your comment.
Orion
am 6 Nov. 2014
Bearbeitet: Orion
am 6 Nov. 2014
Sure you can.
a sine wave is defined by
y = A*sin(w*t+phi).
if you define A as a function(vector) dependant of the time, then you get a sine wave with varying amplitudes.
t = 0:0.01:10;
w = 8*pi;
phi = 0;
A = floor(t); % why not
y = A.*sin(w*t+phi);
plot(t,y);
I did it in matlab, but you can obviously do it with simulink (don't know what tool you're using).
1 Kommentar
Youssef Khmou
am 6 Nov. 2014
Nuchto, That is the amplitude modulation, it is possible to simulate that type of signals:
x=real(exp(j*2*pi*(0:0.1:10)));
y=rand(size(x)).*x;
subplot(1,2,1), plot(x);
subplot(1,2,2); plot(y): title(' random amplitude');
4 Kommentare
Image Analyst
am 7 Nov. 2014
Time Domain Frequency Domain
real hermitian (real=even, imag=odd)
imaginary anti-hermitian (real=odd, imag=even)
even even
odd odd
real and even real and even (i.e. cosine transform)
real and odd imaginary and odd (i.e. sine transform)
imaginary and even imaginary and even
imaginary and odd real and odd
Siehe auch
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