Cannot plot Fourier Transform
Hi Reza, If you take a look at X, the result is X = -((pi*w*sign(w))/2 + fourier(cos(4*t)/t^2, t, w)/2)/pi^2 which shows tha...

2 Monate ago | 0

IFFT integration doesn't match cumtrapz integration
Hi NIk, This is an Interesting problem. Let g be the function and G its integral. If you just want to key in on an improved r...

2 Monate ago | 0

Obtain eigenvalue from matrix and known eigenvector
Hi Henry, you can find the indices where x = 0 and cast those entries out of both x and the corresponding rows and columns of A...

3 Monate ago | 0

fftshift with even and odd number of data points (scaling the positive and negative frequency axis)
Hi Farooq, [1] For N odd, the frequencies before and after using fftshift (or ifftshift) are as you say: N = 9 example: fo...

3 Monate ago | 1

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Getting a smooth curve instead of two linear functions
Hi Arber, This can be done reasonably well by a hyperola whose asymptotes are the two lines in question. The hyperbola of cour...

3 Monate ago | 2

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eigs bug for 0 as lowest eigenvalue in parts of the matlab versions
Hi pl, 2018b does not list 'sa' as an option for eigs, so I am speculating that that 'sa' is legacy. However, compariing 'sa' t...

3 Monate ago | 0

Reduce the computional time to calculate the mutilplying two matrixes
Hi Thu, try % N = 1000; % M = 200; Q00 = reshape(Q0,N,N*M); ff = reshape(w'*Q00,N,M)'; This is approximately four times f...

3 Monate ago | 1

sine fit in matlab vs closed-form expressions (linear least squares)
Hi Thales, Before doing the least squares calculation it makes sense to try the less ambitious result of finding the right ampl...

3 Monate ago | 2

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Replace vector of idexes with values from another vector corresponding to those indexes
Hi Nate, c = b(a) gets it done. a becomes an index vector into the elements of b.

3 Monate ago | 1

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Division problems wiht matrix, calculation error
Hi Eduardo, It's quite likely that two of the displayed values for LineInf and LineSup are not what you think they are. The va...

3 Monate ago | 0

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Audio fft shape is too strange.
Hi eunbae, The code is pretty close. The fft of a real signal has positive and negative frequencies, and what you are seeing a...

3 Monate ago | 1

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Is It possible create a function that, given an equation, finds the value of the (x) so the two members are equal?
Hi Gianmarco, the two equations aren't coupled, and using fzero on Mp^2 seems to work. In the first equation I multiplied by b...

4 Monate ago | 0

Defining derivatives in ode45
Hello sina, If you turn the diagram around by 180 degrees and then let Ca <--> Cb, you get exactly the same diagram that you st...

4 Monate ago | 1

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3d Hemisphere transformation Problem from A to 90 degrees in Z axis to B direction
Hi Musa, In the figure you don't say which axis is which, but I will assume +x axis out of the page toward the viewer, +y axis ...

4 Monate ago | 1

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Binomial simulation decreasing error
Hello LD Using M in place of your i, the binornd(M,p*ones(1,N)) creates N draws from a particular binomial distribution. Thi...

4 Monate ago | 1

HI rabindra, The expression has a problem at the first point, lambda = 0. But I1 is so tiny near the origin that you can safel...

4 Monate ago | 0

Phase shift - different results with pi/2 and 1.570796326
Hi Buli, Although I don't have simulink, I think it is reasonably clear what is going on. I will assume here that -pi/2 is the...

4 Monate ago | 2

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to find the root of quantum transcendental equation
Hi pl, The boundary condition K*cot((KR) = -k (denoted by bc1 below) is for a wave function that is proportional to sin(KR) in ...

4 Monate ago | 0

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Solving inequalities without Symbolic Math Toolbox
Hi Andrik, I'm not sure why you are calling these equations 'inequalities', but if you are looking for a numerical solution to ...

5 Monate ago | 0

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Circularly exclude elements.
Hi Abhijit, try x = 1:n; x(mod([k-1 k+1]-1,n)+1) = []

5 Monate ago | 1

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1st element of the 'Amplitude' of a fft function
Hi NIma, As you point out, signal_FFT(1) is the sum of all the X values (or the mean if you divide by the number of points in X...

5 Monate ago | 1

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Select which legend entries to use depending on data set plotted
Hi Henry, A simple way to do this is, when a trace does not exist, substitute it with nan(1,n) or nan(n,1), keeping the array t...

5 Monate ago | 0

How to plot a numerical integral using the trapezoidal method
Hi Mahdi, I believe your units are correct, although dividing by D gives normalized conductivity and not absolute conductivity....

5 Monate ago | 0

FFT and IFFT: Random Phases
Hi Nycholas, Assuming signal is real and of length n, n even, then Y(1) is for frequency 0, the DC contribution, and it's real...

5 Monate ago | 1

Difference between x*(1e-n1) == x/(1en2)??
Hi Rob, The difference comes down to rounding of the very last digit in binary representation. It's interesting to use 'format...

5 Monate ago | 1

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In the "ex_simrf_adc", there is a 50 Ohm connection with the voltage of 0.1 micro Volt input and it is converted to -142 dBm input and I am not able to get the exact power calculation. Could you please show me?
Hi Charles, I don't have simulink, but to convert from Vrms to dBm, dBm = 10*log10(Vrms.^2/50) + 30; Here Vrms.^2/50 is the p...

5 Monate ago | 0

problem of pdepe!
Hi Junyi, When you made the change, the flux went down by a factor of 1/pi^2. That's fine, but one of your boundary conditions...

6 Monate ago | 0

how do i plot sin(2pi*3t) * sin(2pi*15t)
Hi Jesus, what they are saying is % .* for element-by-element multiplication y=sin(2*pi*3*t).*sin(2*pi*15*t);

6 Monate ago | 0

My matlab plot is blank when I plot
Hi Henry, In the definition of H1, use ./ instead of / so you get term-by-term division. To spot the error, one straighforwa...

6 Monate ago | 1

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