# 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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### Change phase of the output of a buffer

I have a question about changing the phase of a buffer. Question - How to change the output phase of a buffer by 90 degrees, 180 degrees, and 270 degrees? I know to change the phase by 180 degrees, ...
28 views

### Explain if the following processes are stable or not

I have got a question about my homework and was wondering if anybody could help. In the picture below you can see the processes. I need to determine whether they are stable or not. Now I have only ...
54 views

### DFT frequency resolution exercise [closed]

I have a discrete signal that goes as follows: $$x[n]=[-1,4,-1,0]$$ I have already done the DFT for the signal, with the following result: $$X = 2, X=-4i,X=-6,X=4i$$ But for some reason, I ...
28 views

### To find the impulse repsonse using the difference equation

A causal linear time-invariant filter has transfer function a) Denote the input signal by x[n] and the output signal by y[n]. Find the difference equations for the filter. f) Find the impulse ...
30 views

### Signal to Quantization noise problem

a full scale signal of bandwidth 5 khz is sampled by an 10-bit ADC at a sampling rate of 2 Msa/sec calculate the Signal to Quantization noise of the resulting DT signal repeat for a 14-bit ADC at ...
39 views

### How can I obtain the response signal for this question?

In particular I am having trouble with 6b). From what I understand, we can split a difference LTI equation into two sums, the sum of the previous responses, and the sum of the previous inputs. ...
43 views

### Fourier Series representation of a signal

Use the defining equation for the Fourier Series coefficients to evaluate the Fourier Series representation of the following signal: $$x(t)=\sum_{m=-\infty}^{+\infty}=(\delta(t-m/3)+\delta(t-2m/3))$$...
24 views

### ROC and impulse response

For the LTI system given below, there are three regions of convergence. $$H(z)=\frac{5-3z^{-1}}{1-\frac53z^{-1}-\frac23z^{-2}}$$ a) Find all possible regions of convergence for this filter. b) For ...
34 views

Given $y[n]=h_1[n]x[n]+h_2[n]x[n-1]+h_3[n]x[n-2]$ is an LTI system with unity gain at $\omega =0$ and zero gain at $\omega =\pi$. $h[n]\neq0$ .Also given that the system has a linear phase. Compute $... 2answers 225 views ### Finite impulse response FIR filters If H(Z) is linear phase FIR filter, then what can 1/H(Z) represent? Can it be causal and stable? Can it be stable if it is not required to be causal? I think it represents non linear phase FIR ... 1answer 69 views ### Sampling period I started it but didn't how to continue , any help ? 1answer 57 views ### Derive DFT of$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 ... 1answer 44 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 ... 1answer 76 views ### Recovering a signal after filtering A signal$x[n]$is to be transmitted over a communication channel. The communication channel is described by an FIR filter of length$M$such that the received signal is given by $$r[n]=\sum_{k=0}^... 0answers 54 views ### Calculating output of a digital system signal with a filter that introduces delay We have a step function at the entrance that goes through the following system. The D(z) digital filter introduces a 0.25s delay. Output as y(kT) must be calculated. How can we tackle this problem?... 2answers 77 views ### Determine the Given system is linear or nonlinear [closed] Does the following define a linear or nonlinear system?$$ y(n) -4 y(n)y(2n)=x(n) $$0answers 31 views ### Calculating the number of MACs in a system I want to calculate the number of MACs. I am looking for the method. How would I do it if I know the domain equations from a biquadratic digital filter. I have already calculated the Z domain ... 1answer 60 views ### Computing response of LTI system in terms of its step response I have solved a problem, Kindly help me in determing if I solved it correctly. I will post the question and my own working below. Problem My working 1answer 341 views ### How to prove a filter has linear phase response? I have designed an FIR filter to have linear phase response using odd-symmetry design. The coefficients of this filter are {2,1,3,1,0,-1,-3,-1,-2}. I am now being asked to prove it has linear phase ... 0answers 56 views ### FIR Kaiser Window Discrete Time Filter Design Please look at Part (c) of the question. How do we know that the Filter is a Low-pass or High-pass and is the filter designed in C a multi-band-pass filter. 2answers 203 views ### Question About Sampling White Noise Assuming that we have a continuous signal v(t)$$v(t) = \int_0^t g(u)\, \mathrm du\tag1$$where g(t) is white noise.Then take the derivative of it.$$\frac{\mathrm d}{\,\mathrm dt} v(t) = g(t)\... 1answer 26 views ### 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 ... 1answer 49 views ### 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. 1answer 174 views ### 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)? 1answer 101 views ### 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 ... 0answers 81 views ### OFDM system with cyclic prefix I have: Bit rate$ R_b = 25.6 [Mbit/s]$Sampling frequency at the input of the receiver:$ f_p = 8 [MHz]$Protective spacing between successive OFDM symbols:$ τ = 16 [µs] $The combined length of ... 1answer 67 views ### QAM constellation coder - transmitting a file The file with size 6 MB is transmitted in 100 seconds using a constellation coder QAM with a constellation of 6 bit/symbol$ { M = 10^6, B = 8} $Tasks: 1. What is the signal bandwidth if the band ... 0answers 73 views ### OFDM modulator: Transmission time calculation I have a problem with a certain task. The frequency of the signal sampling at the OFDM modulator output is 20 MHz. The length of the protection period is 2 microseconds and it is 20% of the ... 0answers 31 views ### Synthesizing a function from a fourier transform So I have this question in a homework and cannot seem to solve it no matter what I try. Question: Use Matlab to find out what function in time x(t) resulted in the Fourier Series ... 1answer 212 views ### Amplitude and Phase spectrum of a signal [closed] Please help me to solve this question. 2answers 34 views ### Is this calculation of inverse z-transform proper I wonder whether my calculation of inverse z transform are correct. My IIR system is described as follows in Z-domain$H(z) = \frac{z^{-2}}{1-0.5z^{-2}}$After using partial fraction decomposition I ... 3answers 111 views ### Inverse z-transform. Where is mistake? I've already wrote about that trouble (link here), but I don't understand where I've made a mistake. Full description of the task is as follows: Z-transform of sequence {x(k)} describe by the ... 2answers 120 views ### Trouble with inverse Z-transform and calculating of samples I have a little problem. I have to solve this task but I can't. Z-transform of sequence$\{x(k)\}$describe by the formula: $$X(z) = \frac{2.5 -3.15z^{-1} + 1.2 z^{-2}}{1-2.3z^{-1} + 1.2z^{-2}... 1answer 78 views ### Sketch the following Signal: x(t)=3\sin(\frac{\pi t}{4}) [closed] I feel kind of overwhelmed by it, and would like someone to walk me through the steps of sketching the signal. 1answer 76 views ### How do I know what is causing the noise in my signal I have a noisy audio file, available here (It is safe to download if you wish to) https://ufile.io/pstrt Now, I inspect it in matlab: And then i plot it on normalised frequency: Now I need to ... 1answer 23 views ### Implementing echo on adsp 21262 [closed] I'm working on an echo implementation on the board adsp 21262. I've added a buffer to have more samples to work with. I end up then with 4 buffers of size 2048 each. The problem is that I need to ... 0answers 58 views ### How to calculate the magnitude of rounding error in N-bit signed fixed-point arithmetic? In example take into consideration 11-bit <11,5> signed fixed-point arithmetic. 000000.11111 - 0.96875 000001.00000 - 1 so the error magnitude will ... 1answer 46 views ### Transfer function: from poles and zeros to polynomial coefficients I understand how this transfer function was solved except I don't know how to get the 0.87. Any help would be appreciated. 2answers 1k views ### Using Fast Fourier Transform to determine musical notes Hi guys i am doing a course in Digital Filters and Spectral analysis. We are given a coursework/homework, and I have absolutely no idea what to do with it. I come from Maths background, never done any ... 0answers 64 views ### Solving the PDE of a signal in an optical fiber Disclaimer Please let me know if this is not the right place to ask this question. Disclaimer Part 2 I have no background in signals. My focus is in mathematics. In my programming class, we are ... 2answers 763 views ### Calculating N-point DFT of a signal based on another signal's DFT Recently I have asked this answer. Now I would like to know a little bit more about expressing N-point DFT's of signals in terms of one another. Having N-point DFT X(k) of a certain signal x(n), ... 1answer 61 views ### State space equations I am stuck on this exercise. I don't know how to deal with this squared y in the denominator. What am I supposed to do to obtain state space equations? ex.1 Simplified dynamic model of the steel ball ... 2answers 791 views ### Determine whether the system is linear? T(x[n]) = ax[n] + b T(\alpha_{1}x_{1}[n] + \alpha_{2}x_{2}[n]) = \alpha_{1}ax_{1}[n]+ \alpha_{2}ax_{2} [n] +b \alpha_{1}T(x_{1}[n] ) + \alpha_{2}T(x_{2}[n]) = \alpha_{1}(ax[n]+b) + \alpha_{... 1answer 119 views ### Block diagram of filter Can you help me with this question. Can you explain where i should start to solve the problem. 2answers 2k views ### Difference between causality and memorylessness I have found the particular definitions. Causality means that the output of the system does not depend on future inputs, but only on past input. Memory-less - does not depend on previous values of ... 1answer 88 views ### Calculating an output of a system (Z- transform question) I have a following question to answer: An LTI system is described by its impulse response h[n]. For input x[n] it gives output y[n].$$h[n] = u(n) - u(n-N) x[n] = u(n) - u(n-M)$$I want to ... 1answer 839 views ### Expressing 2N point DFT in terms of N point DFT I have a problem with expressing odd samples of X2 in terms of X1. I understand that the resulting DFT will be more precise in terms of expressing the exact spectrum of signal x[n], due to more ... 1answer 374 views ### partial fractions expansion inverse Z-transform, help I have the correct solution from teacher's solution guide, but I was slightly confused by some algebra about the partial fractions expansion evidently difference equation is as follows$ y[n] = \...
I just wanted to doublecheck answers for my sanity's sake (exam next week) problem statement recurrence relation, solve it $y[n+1]= 35 + y[n]*0.5$ according to my teacher it will be such that the ...