Recent content by Davidlong

  1. D

    LTI systems- frequency response

    So if there's 2 sinc functions do i have 2 different integrals? So for example with limits Fc to fc-BW/2 and fc+BW/2 to Fc? For a low pass filter the sinc function is 2.Fc.sinc(2.Fc.t) when the limits are Fc and -Fc. But I'm not sure how to achieve this if it's a band-pass filter.
  2. D

    LTI systems- frequency response

    Yes it's a low pass filter. Do I use eulers formula to factor the exponentials and then apply the trig function? For the frequency response the equation ends in dt, so its a function of t. For impulse response it ends in df so the impulse response is a function of f. Am i correct on this?
  3. D

    LTI systems- frequency response

    This is the code I've written in Matlab; Fc=500; %filter frequency BW=80; %bandwidth frequency F2=Fc+BW/2; %upper limit F1=Fc-BW/2; %lower limit Fs=11025; %sampling frequency Ts=1/Fs; %sampling time IRF=(1/(2*pi*1j*Ts))*(exp(2*pi*1j*F2*Ts)-exp(2*pi*1j*F1*Ts)); %impulse response...
  4. D

    LTI systems- frequency response

    I have the following equation for finding the impulse response function. The equation is the inverse Fourier transform of the H(f) equation.(infinity and -infinity are the limits) h(τ)=∫e(2∏jfτ)H(f)df. I replaced the limits with f2 and f1 which represent F+BW/2 and F-BW/2 respectively. For...
  5. D

    LTI systems- frequency response

    I have attached an image of a ''brick-wall'' band pass filter. Can someone please help me find the expression of frequency response for it? Homework Statement Homework Equations The Attempt at a Solution
  6. D

    Engineering Help with circuits-reactive networks question

    For R i found the equivalent resistant. R8 and R9 in parallel so the resistance when they are combined is 46. Then this new resistor is in series with R7 so they are added together to give 138. C is 0.0001 farads as it says in question 1. so time constant is 138 x 0.0001=0.0138 0.0138 x ln0.5 =...
  7. D

    Engineering Help with circuits-reactive networks question

    For the 3rd question i used the formula V=Vo e^(-t/RC) and i got 0.00957 seconds for t. Does this seem correct as its very small. For the fourth question i used the formula P=V^2/R, 21.91^2/92=5.21739, then i multiplied it by 1000 to give the answer in mW. Did i use the right numbers for this...
  8. D

    Engineering Help with circuits-reactive networks question

    Sorry i uploaded the wrong file. For the second question i got 109.54 by breaking the circuit down, replacing the capacitors with an open circuit and inductors with a short circuit then using the voltage divider equation. v0 x (R1+R2/R2) = V.
  9. D

    Engineering Help with circuits-reactive networks question

    Here's the attachment. The first question should be 21.91 using the formula from the last post.
  10. D

    Engineering Help with circuits-reactive networks question

    Hi guys, I have this homework question that i have attached. I've done a couple questions but I'm not sure if they are right. For the first question i arrived at 15.49 by rearranging the formula; energy stored=1/2.C.V^2. when rearranged you get the square root of 240 for voltage...
  11. D

    Help with plotting triangular wave

    Ah it was because i didn't put m=max(s) before every maxterm. I have did that now and got a larger peak. 1.192, 1.209 and 1.225
  12. D

    Help with plotting triangular wave

    I guess the peak value is the same for all 3 plots. The only noticeable difference is the sharpening of the edge of the triangle. I assume as convergence occurs there will be less visible change.
  13. D

    Help with plotting triangular wave

    It's not really required. I re-ran is by doing s=0; before all the maxterms and i did get a similar amplitude range for all 3 plots. The peaks don't vary much. The question asks us to provide the peak value hence the reason for hard coding it. Is there a simple bit of code that could...
  14. D

    Help with plotting triangular wave

    I didn't look at the actual amplitude values before, only the position of the peak of the waves. I've posted the m-file
Back
Top