Recent content by Jncik

I understand that having a periodic signal x(t) we can find a signal y(t) which uses harmonically related exponentials in order to construct the x(t) signal each exponential has a frequency and magnitude, for example 3*e^{j 2 \omega} has a frequency of \frac{2 \pi}{2 \omega} =...

Hi everyone, I want to understand how these concepts work. Suppose that we have a signal x(t) which has a maximum frequency component of 3 Hz. So let the DTFT of this signal be like that: http://img341.imageshack.us/img341/1134/31096081.png Also let y[n] be the digital signal that we get...

Hi I'm trying to understand what we mean when we say that the Fourier transform is used to transform a signal from the time domain to the frequency domain and what we actually have in the frequency domain. In Fourier series we are actually using a different representation of the signal in terms...

Homework Statement Hi I was trying to understand an algorithm analysis problem and I came to this point: [PLAIN]http://img820.imageshack.us/img820/1834/unledytw.png can someone explain me what he did there? Is there any other step between that should have been written in order for...

thanks for your reply so, if I took from -T to T it would be an interval 2 times larger than the interval of a period, which is correct right? but if I integrate from 0 to T I will get a different result do you mean by "the same result" that the answer to a question that wants an inner...

Homework Statement Hi suppose you're given two signals for example x_{1}(t) = cos(3 \omega_{0} t) x_{2}(t) = cos(7 \omega_{0} t) and you want to find out the inner product Homework Equations The Attempt at a Solution I mean, it's an integral right? But what will the boundaries be...

thanks a lot ;)

thanks lewando What I was meaning is that x(t) may have two components but the overall frequency is the least common multiple of the frequencies of each of these 2 components right? so the result will be different thus if I understand correctly the result should be 2*f1 = 9 because f1 > f2...

Homework Statement What sampling frequency would you use to sample the following signal x(t) = 3sin(9πt) - 6cos(8πt)Homework EquationsThe Attempt at a Solution let T1 be the period of 3sin(9πt) and T2 the period of 6cos(8πt) T1 = 2π/9π = 2/9 Τ2 = 2π/8π = 2/8 thus, if f1 is the frequency of...

that was a nice alternative thanks a lot for your help :)

thanks I have one more question I think I'm wrong with my FT calculations25g(t-10) \leftrightarrow 25 X(j \omega) e^{-j 10 \omega} but I have 25g(\frac{1}{8}(t-10)) hence 25g(1/8(t-10)) \leftrightarrow 200 X(j 8 \omega) e^{-j 10 \omega} I mean I should first find 25 g(1/8 t) and then...

Yes you're right 25g(1/8(t-10)) \leftrightarrow 200 X(j 8 \omega) e^{-j 80 \omega} "Also, I'm not sure where you got the overall factor of 1/8 in front." isn't 25g(1/8(t-10)) = x(t)? for g(1/8 t - 10/8) and the first interval I will have 1 - |\frac{t}{8} - \frac{10}{8}| for...

Homework Statement find the Fourier transform of the function x(t)=\left\{\begin{matrix} &25 - \frac{25}{8}|t-10| &for &|t-10|<8 \\ &0 &for& |t-10|>8 \end{matrix}\right. Homework Equations The Attempt at a Solution we know that g(t)=\left\{\begin{matrix} &1-|t| &for &|t|<1 \\ &0...

thanks a lot :)

Homework Statement find \sum_{-N1}^{+N1}e^{-j\omega n} Homework Equations The Attempt at a Solution Let \lambda = e^{-j\omega} we have \sum_{-N1}^{+N1}\lambda ^{n} = \sum_{-N1}^{-1}\lambda ^{n} + \sum_{0}^{+N1} \lambda ^{n} for the first i have S = \lambda...