Questions tagged [signal-theory]

Anything related to signal theory, i.e. the branch of applied mathematics and engineering studying the properties of signals and the mathematical tools used to manipulate them.

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2answers
94 views

Can signals pass through a single wire in both directions simultaneously?

Can electric signals pass through a single wire in both directions simultaneously? To be clear, I mean signals that are not somehow modulated to avoid interference. I also mean a wire, and not a ...
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3answers
605 views

What is the physical significance of skewness and kurtosis of an eletrical signal?

I understood the mathematical meanings of the skewness and kurtosis. But when we calculate these quantities for a signal (say an electrical voltage signal), what physical meaning do they convey? For e....
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2answers
47 views

How do causality and stability affect the response of a linear time-invariant system?

Suppose that there's a linear time-invariant system with the following transfer function: $$H(s) = \frac{1}{3(s-2)}-\frac{1}{3(s+1)}$$ If the system is causal and stable, I can determine \$h(t)\$ by ...
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1answer
28 views

Evaluate signal power between two amplifiers

Let's consider this cascade of amplifiers: Consider the intermediate node, and suppose there our signal has voltage Vx. How can I evaluate that signal power (for instance to calculate the SNR, ...
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0answers
16 views

Parseval Theorem and RMS

I was just thinking that when we have $$ \overline{|v(t)|^2}=\frac{1}{2t}\int_{-t}^{t}|v(\tau)|^2 d\tau $$ we couldn't apply Parseval theorem, for it is normalized. For applying Parseval Theorem, we ...
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1answer
29 views

About discrete time model for wireless channel

I am trying to understand Section 2.2.3 of the book "Fundementals of wireless communication" by Tse and Viswanath. In this section the authors explain how to go from the continuous time ...
3
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1answer
76 views

How to modify zeros and poles in a delta-sigma modulator loop?

In this specific case, I am modelling a delta-sigma analog-to-digital converter with a basic loop in which the output V is fed back with unity gain to be subtracted from the previously sampled input U ...
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0answers
23 views

Calculating the Running Corrleation of two signals in Matlab

I am currently using https://www.eecs.umich.edu/courses/eecs206/public/lab/ to advance my matlab skills. Sadly I am stuck at lab2 task 2. First, i cant run the pcode file to get the proper solution ...
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7answers
1k views

Why is power of a signal equal to square of that signal?

Is there any logic as to why the power of a signal \$\mathrm{x(t)}\$ is taken as \$\mathrm{x^2(t)}\$? I searched everywhere and there's no clue. My professor told: "It's a standard result so shut ...
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5answers
2k views

Is Gaussian noise equal to white noise?

If noise on a signal is randomly fluctuating in time domain around its mean following a Gaussian normal distribution (Gaussian noise), would this be equivalent to an constant intensity in the ...
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5answers
165 views

Why frequency of a DC signal is chosen as zero? If the period can be anything, isn't it same for frequency?

This is a page from Oppenheim. We can assume a DC signal as a repetition of 10 strips per 10 seconds/10 strips per 5 seconds. Like that, if we choose different periods, we get different frequencies ...
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2answers
145 views

Time Reversal Operation for discrete time signals

For a discrete time unit step signal 'u(n)' , if time reversal operation is performed then it becomes 'u(-n-1)'. Is it true for ANY discrete time signal 'x(n)' such that time reversal operation makes ...
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3answers
110 views

convolution vs correlation?

Apparently this question looks better for DSP SE but I am posting it here to get answer in simple words for those EE graduates who didn't studied signal processing in undergrad. Apparently as far as ...
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3answers
116 views

Aperiod vs Period waveform Fourier Transform: How does nature understand which is the case?

Today I reviewed the theory behind the Fourier Transform, and I asked myself a question that I couldn't answer to in the process. Theory: A periodic waveform has a Fourier series which can be seen ...
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2answers
97 views

What is the math behind high FM frequency components being more noise prone? [closed]

what is the math behind the phenomena that higher frequencies are more prone to noise? The use of pre-emphasis to boost the higher frequency components to get a better S/N ratio. Can you provide ...
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1answer
46 views

Doubt on singular value decomposition

I am studying control systems and I am studying the topic of Singular Value Decomposition(SVD). I have found a transfer matrix of a systemm, and computed its DC gain. Then I have performed the ...
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2answers
88 views

Why does a pole at high frequencies attenuates noise?

I am trying to understand the concept of realizability for an improper transfer function, and I am struggling to understand some concepts. I know that if I have an improper transfer function, for ...
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3answers
74 views

How to construct a signal with only unit functions?

I don't understand the solution to this problem. How can I write a ramp function in the form of a step function?
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0answers
24 views

Cellular communications queuing

Not sure if this is the right place to ask but this is a homework question. Consider a base station in a cellular network. The base station has the resources to handle 7 calls at the same time. The ...
15
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3answers
4k views

Why do microwave ovens use magnetrons?

With a lot of advancement in solid state electronics and signal manipulation, isn't it easier to simply take high amplitude signals with frequencies near 1 MHz and multiply the signals using diodes ...
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1answer
28 views

Draw the graph of differential of the following graph

Is is like this? I think there should be impulse signal also in the graph am i doing wrong?
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1answer
70 views

Represent the given signal in mathematical form

Is this the mathematical form? I highy doubt myself $$ -2r(t+3)+2r(t)+16u(t)-r(t)-2u(t-3)+5/2r(t-3)-5/2r(t-5) $$
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1answer
104 views

Draw even and odd parts of following signal

I think my odd signal is wrong because odd signal cannot be symmetric about y axis
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1answer
89 views

Calculating steady state output using Laplace transform

I've tried to obtain the the steady state output with the help of final value theorem and multiplication properties of Laplace transform.But I'm not sure whether I've solved the problem correctly or ...
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1answer
105 views

Confusion regarding step responses of integrator and differentiator?

I am using matlab to study about step response of integrator and also of differentiator using transfer function modelling technique But i have two confusion, one in case of integrator is that step ...
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2answers
66 views

Determine the output signal given the input and inpulse response

It's been a while since I've worked these types of problems, but I've been working out the following problem for a while now and can't figure out a few details: And here is the solution: ...
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0answers
90 views

Is diode reverse recovery time related to diode capacitance?

The title. Is there some relationship between the two parameters? For example, fast diode recovery time indicates low capacitance, or even farther, can one be calculated from the other? Thank you in ...
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1answer
292 views

Colpitts oscillator: how to reduce amplitude thermal drift?

I have built this circuit, supply ±12V: I am using a LM6172 amplifier. I have found the transfer function of the filter involved: \$H(j\omega)=\frac{1}{1 + \frac{R_3}{R_1} - L\omega^2(C_2+C_1\frac{...
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3answers
174 views

Colpitts oscillator : having trouble while respecting Barkhausen criterion, is this criterion insufficient there?

I'm trying to simulate a Colpitts oscillator. I've determined transfer function of the low-pass filter of this circuit: I reached this expression: \$H(j\omega)=\frac{1}{1-LC_2\omega^2+jR_3\omega(C_2+...
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1answer
38 views

Minimum Shift Keying

"Overall frequency excursion del-f in MSK is minimum frequency spacing between symbols 0 and 1 that allows their FSK representation to be coherently orthogonal". What is meant by being coherently ...
3
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3answers
733 views

Do I need to maintain source of a signal till it reaches the destination?

If I send a signal through a wire having delay of 10ms, then should I need to maintain the source of the signal till it reaches the destination or can I change after, say, 2ms and send the next signal....
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5answers
226 views

Why can't all data be sent across 4 wires?

I am aware that USB uses a positive, negative and D+/- wires in order to transmit data. The twisted pair are used to negate the effects of interference and electronic noise. I also understand that a ...
5
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3answers
1k views

Is there any relationship between frequency of signal and distance it travels?

I'm currently researching 5G technology. Many videos/articles on this topic claim that 5G is designed for communicating on lower distances (than 4G), because of higher (than 4G) frequency. So to build ...
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1answer
339 views

Long Distance High Speed Wireless Data Transfer

What kind of device can I use to transmit data at a rate of 1MB/min up to a distance of 100 miles? If that's not possible, what's the farthest distance to which I can transmit the data.
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1answer
46 views

Contradiction while using the convolution sum for a non-LTI system

In a recent quiz, we were given the following problem: The cascaded LTI systems \$\mathcal{T}_1\$ and \$\mathcal{T}_2\$ respectively have impulse responses \$h_1 \lbrack n \rbrack = \delta\lbrack n ...
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4answers
188 views

Sampling Theorem and reconstruction

I do not understand a concept about the Nyquist - Shannon sampling theorem. It says that it is possibile to perfectly get the original analog signal from the signal obtained by sampling if and only ...
5
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3answers
323 views

Why the Wien Oscillator output is a sine?

I don't understand why the output signal of the Wien oscillator is a sinusoidal waveform. I can easily understand how a sine waveform can be generated by an oscillator which contains an LC circuit (...
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1answer
256 views

Derivation of the Shannon Limit

I am doing the derivation of the Shannon Limit, and I think I ran into a snag, and am in need of a bit of assistance: Background: From information theory, we know that the Shannon Limit is: $$C = W *...
2
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1answer
54 views

How to use my bits to transmit this photodiode signal in the most efficient way possible? [closed]

Suppose I have photodiode with a Dark Current of 5 pA and that using the NEP of that photodiode at some frequency \$\lambda\$ I determined that the smallest signal I could detect was of 1 pA. First ...
0
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1answer
48 views

Why microstripline is compulsory to generate high frequency signal in the range of 2 Ghz or more

I would like to understand why the UHF (Ultra High Frequency) band in the range of 1 Ghz or more like 2.4 Ghz or 2.6 Ghz require microstripline to generate such signal frequency? Is there any ...
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1answer
114 views

Find admittance( G ) matrix of a resistive circuit

I am taking Signals And Systems class where I have to calculate the admittance parameter of a given circuit. A given circuit for example: This is tedious and calculating the parameters takes so long....
0
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1answer
364 views

How do you visualize the frequency spectrum for a digital waveform? [closed]

How does the mathematics of a single or periodic rectangular pulse help us quickly visualize the frequency spectrum for a digital waveform? Develop the ideas behind this. My professor posed this ...
3
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0answers
103 views

What is the signal-noise model of laser induced fluorescence?

The following image is an example of a fluorescence signal trace from the photomultiplier tube detector (PMT). Each spike represents one fluorescently labeled cell. This signal model is definitely ...
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4answers
84 views

Is a voltage signal we observe on scope made up of only cosines?

Pardon me for the dumb looking question but I'm trying to comprehend a "signals and systems" subject and relate it to voltage or current signal. A periodic signal is made up of sinusoids which is a ...
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2answers
2k views

Does a splitter still reduce signal if only 1 of its ports is used?

I'm using a Wilson Electronics signal amplification system to try to get phone signal in my house. I'm going to attempt using a coaxial splitter like this one to split the amplified signal to multiple ...
3
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2answers
13k views

How can I determine the order of filter?

This is my first study about signal analysing. I'm very confused about filter order. My problem is how can I know whether its 4-th order, 12-th order, or 2nd order like the book says so? I'd like to ...
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0answers
37 views

What effects limit throughput of a short channel?

In a short channel, e.g. a 1" long Ethernet cable, which effects are most likely to reduce throughput and why? What would the nature of the throughput reduction be? Specifically, I am wondering about ...
2
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1answer
336 views

What is the difference between SNR of a wideband system and the SNR for a narrowband system

I was reading Wireless Communications by Andrea Goldsmith in the book the author has stated that the Noise power for a wideband system with Bandwidth B is (B*N/2). Could someone help me understand why ...
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2answers
117 views

General questions about the telephone line a.k.a “last mile” [closed]

Before the digital data gets conveyed over the "last mile", it passes a modem, which converts this digital data into audio signals (Which is often called analog) (but the binary system still is there, ...
7
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3answers
2k views

Why the resultant period of two signals is the LCM of the individual period of that signal? [closed]

Suppose a signal is constructed using two independent signals(say S1 and S2)both S1 and S2 have two different individual frequencies.The resultant signal that has been constructed has a new frequency,...