# Questions tagged [homework]

Homework means the asker is requesting help with school homework. This lets potential answerers know that they should guide the student in solving the problem, rather than simply showing the complete answer.

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### Calculating the magnitude spectrum and phase spectrum

From a window function $x(t)=u(t+2)-u(t-2)$, we can get the Fourier Transform $X(j\omega)=\frac{2\sin(2\omega)}{\omega}$. Then, I want to calculate its magnitude spectrum and phase spectrum. The ...
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### Frequency response and corresponding magnitude response

I'm given this frequency response: And I want to find the corresponding magnitude response. My answer is $|H(e^{j\omega})|$ = 1 if $|\omega|$ is within $\frac{\pi}{2}$; 0 otherwise. Is this correct?
37 views

### How to match zero-pole diagrams to their frequency responses (Discrete Time)

I get confused when there are a lot of zeros/poles in the zero-pole diagram and I find difficulty understanding their frequency response. I know the following: 1. Complex conjugates cause double ...
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### Finite impulse response FIR filters

If H(Z) is linear phase FIR filter, then what can 1/H(Z) represent? Can it be causal and stable? Can it be stable if it is not required to be causal? I think it represents non linear phase FIR ...
79 views

### Sampling period

I started it but didn't how to continue , any help ?
61 views

### Derive DFT of $x((n+1)/2)$

If $X(k)$ is the $N$-point DFT of $x(n)$, and $y(n)= x\left(\frac {n+1}{2}\right)$ for odd $n$, and $0$ for even $n$. What is the $2N$ point DFT of $y(n)$ in terms of $X(k)$? So far, I've ...
59 views

### Which of these signals have same Nyquist rate as $x(t)$?

The options are: $x^2(t)$ $x(2t)$ Time derivative of $x(t)$ Convolution of $x(t)$ with itself I guess, the Nyquist rate remains the same as long as bandwidth of $X(w)$ remains the same, as Nyquist ...
79 views

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### Equivalence of difference equation with system of difference equations

I have this system and tried to write down its difference equation as follows $$y[n] = b_0v[n] + b_1v[n-1]\\ v[n] = x[n] - a_1v[n-1]$$ I was asked to prove that the system can be ...
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### Consider the integrator and check for time invariance

I'm trying to check the following system for for time-invariance. $$y(t) = \int_0^t x(\lambda) d\lambda$$ Please explain me why it is time-invariant.
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### Extract approximation and detail coefficients

I am a student and would like to know how to extract the approximation and detail coefficients (A5, D5, D4, D3, D2 and D1) after an applied DWT decomposition dB5 (Daubechies 5, level = 5)?
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### Inverse Fourier Transform From Plots (2019 edition) [closed]

Hello I borrowed the title for another post. I cannot figure out how to find the inverse fourier transform from this spectrum. I know what the transform is I'm sorry for the plot being hard to ...
68 views

### QAM constellation coder - transmitting a file

The file with size 6 MB is transmitted in 100 seconds using a constellation coder QAM with a constellation of 6 bit/symbol ${ M = 10^6, B = 8}$ Tasks: 1. What is the signal bandwidth if the band ...
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### OFDM modulator: Transmission time calculation

I have a problem with a certain task. The frequency of the signal sampling at the OFDM modulator output is 20 MHz. The length of the protection period is 2 microseconds and it is 20% of the ...
268 views

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### Is this calculation of inverse z-transform proper

I wonder whether my calculation of inverse z transform are correct. My IIR system is described as follows in Z-domain $H(z) = \frac{z^{-2}}{1-0.5z^{-2}}$ After using partial fraction decomposition I ...
117 views

### Inverse z-transform. Where is mistake?

I've already wrote about that trouble (link here), but I don't understand where I've made a mistake. Full description of the task is as follows: Z-transform of sequence {x(k)} describe by the ...