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5 votes

How to set parameters of the PI controller inside the PLL?

Two suggestions to move forward: Reduce $K_i$ to the point of an acceptable overshoot (this will provide the bottom line answer for comparison to the computations. Do system identification (Bode ...
Dan Boschen's user avatar
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4 votes
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How do I get a faster system response?

The transfer function is $H(s) = \frac{16.94s + 579.5}{s^2 + 507.2s + 1224}$ This transfer function has 2 poles, one slow pole at -2.4248 and a fast pole at -504.7752. The function has a slowish zero ...
Ben's user avatar
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3 votes

How to set parameters of the PI controller inside the PLL?

1 There's a mistake in the PID connection. You must feed the quadrature component, i.e $U_q$ to the PID, not $U_d$. The setpoint of your PLL is $U_q = 0$ because you want your PLL to be in phase with ...
Ben's user avatar
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2 votes

How to model state space for complex valued system correctly in SIMULINK (MATLAB)?

You can split up the real and imaginary part of the state into their own seperate states. Namely by defining $x_r=\mathrm{Re}(x)$, $x_i=\mathrm{Im}(x)$, $A_r=\mathrm{Re}(A)$, $A_i=\mathrm{Im}(A)$, $...
fibonatic's user avatar
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2 votes

Feedforward disturbance signal compensation

I cannot implement this transfer function in MATLAB Simulink. Is there a way forward? That's because you can't implement it at all. $$ \frac{1}{G_\text{cc}(s)} = \frac{s^2 \text{L} T_\text{I}/K_\text{...
TimWescott's user avatar
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2 votes

How to improve accuracy while converting floating point coefficients to fixed point in the case of an all pole IIR filter

Where are the poles of your filter? If they are close to the unit circle, then quantizing them can cause some of them to cross beyond the unit circle, causing the quantized filter to be unstable. You ...
Ben's user avatar
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2 votes
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How to get Step Response from an Impulse Response in Simulink?

Your system H(s) is continuous $$ H(s) = \frac{s}{s+1} $$ Using a discrete impulse does not make a lot of sense. I suspect Simulink added a "zero-order hold" or ZOH block between your discrete ...
Ben's user avatar
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2 votes
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Analytic Signal Block in Simulink Gives Reduced Amplitude for the Imaginary Part

If the filter has a fixed order then increasing the sampling rate will make its response scale with frequency, thus the transition width increases relative to the sampling frequency. For example: if $...
a concerned citizen's user avatar
2 votes
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What are the spikes here in the spectral analyser?

First rule of reading graphs: Read units, scales and labels. The data in your second graph is between -400dBm and -3400dBm. -400dBm is a power of $10^{-43}W$. That's essentially all zeros and what you ...
Hilmar's user avatar
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2 votes

spectral bandwidth of QPSK signal

Regardless of how $B$ is defined earlier in the Wikipedia article, the equation starting with where the Nyquist rate is introduced is a single-sided bandwidth: $$f_p < 2B$$ Which state that (single-...
Dan Boschen's user avatar
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1 vote
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Why I am having phase difference between original and reconstructed signal in this simulink model?How can i remove it?

As @MBaz mentioned, you have a zero-order-hold block that introduces a delay + a sample time block that can introduce a delay depending on its settings. Not sure about the Encoder and Decoder block, ...
Ben's user avatar
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1 vote
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Why does Simulink generate this code for a PID controller?

I'm not sur exactly where you went wrong because your haven't fully explained your approach but for the derivate component of the PID, you should convert the C++ lines to this : $$ D_{out}[n] = N(err[...
Ben's user avatar
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1 vote
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Is Step the same as an Impulse + 1/s?

The problem is that you can't use a Dirac delta impulse as an input, which would be the theoretically correct thing to do. Since you only have a discrete impulse, which has some finite value, and ...
Matt L.'s user avatar
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1 vote

Complex Data type not accepted in Simulink

The data type of the signal must be fixed in Simulink. Since you use a square root of a real signal, the output will be real if the data is positive, imaginary if negative. Simulink cannot allow that. ...
Ben's user avatar
  • 3,777
1 vote

What channel model to choose while simulating a system in passband with frequencies over GHz range?

However, when I add an AWGN channel, I get pretty low BER of 10^-5 in passband as compared to around 10^-4 BER in baseband under same AWGN channel of SNR 10 dB. Why is it happening? You've got a bug ...
Marcus Müller's user avatar
1 vote

Feedforward disturbance signal compensation

1 - What transfer function are you trying to implement? The controller transfer function or the "plant" transfer function? 2 - You are trying to simulate some kind of inverter/active ...
Ben's user avatar
  • 3,777
1 vote

Understanding Matlab's Automatic Gain Control function

Hi I am confused about the implementation of AGC in Simulink example. I am unable to relate the given implementation to the algorithm given by MATLAB. Kindly help me in understanding the reason behind ...
Rizwan 's user avatar
1 vote
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Understanding Matlab's Automatic Gain Control function

From the diagram in the Algorithms section of the documentation you can see how the different quantities are computed: Note that $z$ in the diagram is an estimate of the output power.$^1$ The error ...
Matt L.'s user avatar
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1 vote
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Length of Matlab Raised Cosine Filter Output Complex Vector

The filter computes OutputSamplesPerSymbol output samples for each input value. You would get the complete convolution if ...
Matt L.'s user avatar
  • 90.5k
1 vote

"Revolving" QPSK Constellation

You are seeing the "Digital IF” carrier assuming you are modelling what you want to implement digitally in VHDL. The sine and cosine blocks together with the multipliers and combiner perform a ...
Dan Boschen's user avatar
  • 52.3k
1 vote
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DFT (FFT) of Non Uniformly Sampled Signal

I am trying to perform an FFT of a non-uniformly sample signal. My input comes from Simulink and PLECS which uses variable-time solver. Assuming that the first column in the data provided is your ...
A_A's user avatar
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1 vote

How do I simulate a purely real signal being received on multiple antennae in an array?

The input at each array will be complex, because the wireless channel "spreads" the energy of the in-phase and quadrature parts of the signal into each other. One simple way to think about this is ...
MBaz's user avatar
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1 vote

How to implement a $1$-bit quantizer in Simulink?

You can see this example of Sigma-Delta A/D Conversion.
Vyacheslav Klimentyev's user avatar
1 vote
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Amplitude value after a Discrete-Time integration calculation?

I figured it out coming back to basic maths, I was making a mistake when integrating my sin function that Matlab block wasn't doing, I was missing behind the $\omega$ variable $$ve[n] = -B \cdot \...
ndarkness's user avatar
  • 113
1 vote

Inverse system in Simulink

If you have the Control System toolbox, you can use a LTI System block to implement the transfer function.
Brian's user avatar
  • 36

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