Creating a cosine oscillation ( cos(2 * pi * f * k * T) )

81 次查看（过去 30 天）
Ahmad
Ahmad 2023-4-10
编辑： Image Analyst 2023-4-10
Hello,
I need help wiht producing a cosine oscillation with sampling frequency = 10KHz and a signal length = 2000 samples. The frequency(f) is equal to 100 Hz and the amplitude is equal to 50. I can't figure out what k exactly is.
Can anyone please help me
Thank you in advance

请先登录，再回答此问题。

采纳的回答

Askic V
Askic V 2023-4-10
Hi Ahmad,
you can can think of k*T as a time vector, one example is:
k = 1:2000; T = 1/Fs;
tf = k*T;
y = A*cos(2*pi*f*k*T);
plot(tf,y)

更多回答（1 个）

Image Analyst
Image Analyst 2023-4-10
编辑：Image Analyst 2023-4-10
Ran in:
A cosine wave is of the form
y = Amplitude * cos(2 * pi * omega * time)
So for your formula
Amplitude = 50;
and I beleve T is your time vector.
omega is the frequency which is f*k for you. I believe f is the lowest frequency, and it's equal to 100, and is what you'll get when k = 1. If you increase k you get harmonics of f so you'll get waveforms at twice the frequency, 3 times the frequency, 4 times the frequency, etc.
If the sampling frequency is 100000 hz, the delta between time samples is 1/10000. So after 2000 samples your time value would be 2000/10000 = 0.2 seconds. So you can construct T, your time vector, using linspace like this:
T = linspace(0, 0.2, 2000);
So in all you get
f = 100;
k = 1;
y = Amplitude * cos(2 * pi * f * k * T);
% Now plot it.
plot(T, y, 'b-', 'LineWidth', 2);
grid on;
xlabel('T');
ylabel('y');
Note you get 20 oscillations (periods) in 0.2 seconds, so you'd get 100 of them in 1 second, as you should with k=1 and f=100. If you increase k you get more oscillations in the same time interval.
I hope this helps explain it better. If it does, could you Accept the answer and/or click the "Vote" icon?

类别

在 Help Center 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

产品


版本

R2023a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by