Recent content by hastings

  1. H

    Derivative of a signal: is it right?

    When I write A\text{rect}_{\Delta}(f-f_0) I mean it's a rect signal with amplitude A (usually a constant), duration Δ and is centered in f_0. So in this case there are 2 rect signals, one centered in -4W on the left and the other one centered in +4W on the right. Both have a duration of 4W...
  2. H

    Derivative of a signal: is it right?

    Hi everyone! I was trying to solve an old exercise but in a different way. It asks to find the signal x(t) given the graphs of |X(f)| and arg[X(f)]. Please refer to the attachment. My stategy this time is as follows: 1) find D(f) by deriving |X(f)| 2) antitransform D(f) and get d(t) 3)...
  3. H

    Fourier Transform: given X(f), find x(t)

    Regarding the 1st addend, is it correct? where Meanwhile I'll work out the 2nd addend.
  4. H

    Fourier Transform: given X(f), find x(t)

    I thought of breaking the equation in 2 pieces: \underbrace{\mathcal{F}^{-1}[ \frac{1}{16}f e^{j2\pi \frac{1}{144W}f }]}_{\text{1st addend}}+ \underbrace{\mathcal{F}^{-1}[\frac{3}{8}We^{j2\pi\frac{1}{144W}f } ]}_{\text{2nd addend}} I know that \mathcal{F}[\delta(t-t_0) ]=e^{j2\pi t_0 f}...
  5. H

    Fourier Transform: given X(f), find x(t)

    Sorry I'm late in replying, I was little busy. So X(f) should be: X(f)= \left\{ \begin{array}{ll} (\frac{1}{16}f +\frac{3}{8}W)e^{-j(-\frac{2\pi}{144W}f)} &, \text{ for -6W $\leq$ f $\leq$ -2W} \\...
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    Fourier Transform: given X(f), find x(t)

    So you're saying the Amplitude should be something like: \frac{1}{16}f +\frac{3}{8}W \mbox{, for -6W \leq f \leq -2W} -\frac{1}{16}f +\frac{3}{8}W \mbox{, for 6W \leq f \leq 2W} \right. As for the PHASE, it should be: \phi(f)=-\frac{\pi}{72W}f Which by the way means that at...
  7. H

    Fourier Transform: given X(f), find x(t)

    That's rather generic. Can you give me another hint for the amplitude? I suppose it assumes the form of a slope: \phi(f)= m\cdot f
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    Fourier Transform: given X(f), find x(t)

    Can someone try and help me? Please :(
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    Fourier Transform: given X(f), find x(t)

    Did I get the module correct? Please help me with the phase, do I have to write a slope's formula?
  10. H

    Fourier Transform: given X(f), find x(t)

    Hi everyone! I'm not sure if I'm posting this question in the right section. Please don't be mad at me if I'm mistaken. Can you please help me solve this problem? Calculate the value of the signal x(t), given its spectrum (see figure in attachment), at the time t=2/W. Attempted...
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    Engineering Circuit analysis: find Network Function

    how? Where do I get another set of equations? seems as though the node method isn't needed to solve this problem. Do I have to make some adjustments and re-write these equations? If so, what are those adjustments? \left[ \begin{array}{ c c c } (\frac{1}{R} + sC) & 0 &...
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    Engineering Circuit analysis: find Network Function

    \left \{ \begin{array}{ll} \frac{2}{3}I_g+\frac{1}{3}I_2 &=E_2 \\ \frac{1}{3}I_g+\frac{2}{3}I_2 &=E_3 \end{array} \right. \left \{ \begin{array}{ll} \frac{2}{3}+\frac{1}{3}I_2 &=E_2 \\ \frac{1}{3}+\frac{2}{3}I_2 &=0 \end{array} \right...
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    Engineering Circuit analysis: find Network Function

    Please see the pic I've attached. Did I get your suggestion right? I thought that since the current is not flowing in the upper part of the circuit because of the open circuit represented by the capacitor, I could just eliminate it with a big red "X". This means that for t>0 the initial...
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