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Questions tagged [signal-power]

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0
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1answer
18 views

Why is carrier wave affected by percentage modulation?

In amplitude modulation, Power of a carrier wave is represented by : $$P_c = \frac{A_c ^2}{2R}$$ Which is independent of modulation index! Question: At what factor is the power of carrier wave ...
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0answers
12 views

Power Value for Frequency spectrum [closed]

How to calculate power value of a fft spectrum ? (equation) and What does it mean
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1answer
45 views

How can I get the power of a specific frequency band after FFT?

I need help with my matlab code. I have recorded EEG data and now I want to analyse it in matlab. I want to find the mean power of specific frequency ranges (theta: 4-8 Hz,alpha: 8-12Hz etc.). For ...
0
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1answer
14 views

SNR in one-dimensional additive channel with uniform noise and binary antipodal input

A one-dimensional addictive noise channel, $Y=X+N$, has uniform noise distribution $N \sim U(-\frac{L}{2}, \frac{L}{2})$ and binary antipodal input constellation with equally likely input values $x=\...
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1answer
38 views

How to calculate the power of a finite length signal?

I am confused with these concepts. If the signal is expressed as r(t), I know the power of the signal is given by: But if the the length of signal T is finite and cannot approach infinity, how can I ...
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0answers
30 views

Is it possible to weight the high frequency components of a signal to give high frequecy components greater overall power in the total signal?

I have a multivariate time-series dataset, and would like to run PCA on my dataset to reduce the number of variables I input into a time-series model. I am concerned that running PCA may end up ...
0
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1answer
27 views

Calculating Power of Sinusoidal Term and a Convolution expression

The following is an excerpt from the book Statistical Digital Signal Processing and Modelling (Monson Hayes) ...consider a random process consisting of a random phase sinusoid in white noise $$ x(...
0
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1answer
29 views

Negative exponential signal's energy and power

Earlier I have dealt with exponential functions multiplied with unit step function. But, energy and power of exponential function alone comes out to be infinite when I put limits of the integrals to ...
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3answers
121 views

Is $\arctan(t)$ an energy or power signal?

Is the function $\arctan(t)$ an energy or power signal? I've tried working out the integrals for energy and power but I get stuck on both.
0
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1answer
33 views

Modulation of real-valued signal

I have one doubt according to modulation of a real signal. there are so many examples where the real signal was modulated with frequency bigger then 0. Why the signal could not be putted in f=0? is ...
1
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1answer
284 views

How to calculate the power of a discrete signal? / Clarification on PSD estimates

I want to calculate the channel power $ P_\mathrm{x}$ of a given discrete and complex signal $x[n]$ (with a length of N) in a given bandwidth $B$. I'm aware, that I could probably apply a sharp ...
0
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1answer
69 views

What unit is the z axis of a power spectrogram of audio?

the question might seem dumb but since I tried it out and got values well above 2000 (watts?) it got me thinking... Check this out: ...
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0answers
24 views

find power of recieved signal of usrp b200 in gnu radio companion

how to find power of recieved signal of usrp b200 in gnu radio companion from frequency sink block (the frequency plot) or any other block available in gnu radio. I am transmitting and receiving ofdm ...
0
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1answer
141 views

Ratio of the power in the sidebands to the total power in conventional AM

Message signal and carrier signal are given as $m=\cos(2 \pi \cdot f_{m} \cdot t) $ $c=A_{c}\cdot \cos(2 \pi \cdot f_{c} \cdot t) $ I was asked to find modulation index $a$ so that ratio of the ...
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0answers
32 views

Detection over a few number of bins

In Periodogram Can I take only few frequency bins (nFFT bins) , sum and compare it with threshold in stead of whole bins . if yes why? with knowledge I pass the data through the window before fft ...
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0answers
40 views

Optimization of a continuous function

This is more like an optimization problem but any solution is appreciated. I have a data set with input specifying power(demand) to be generated for a particular time period(TP). Input: Time --- ...
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2answers
273 views

Calculating the complex signal's average power

$$x(t) = \cos(\pi i t/20+\pi/4) - 2je^{j \,12\pi i t} + 5\sin(2\pi i t/3+\pi/3) $$ I need to find the signal's average power. How can I do that? The $i$ index (represented in red in the below image) ...
0
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1answer
56 views

Confusion in Peak to Average Power Ratio (PAPR)

(1) What does it mean by 'a system with low peak to average power ratio requirement'? Doesn't every system idealises it to be lower? Or there are some exceptions to it? (2) Higher PAPR can be a ...
0
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1answer
48 views

Why the calculated value of power is not match?

I am trying to calculate the power of a signal by using following two methods one is a power of a signal and another one is using the periodogram in Matlab as shown in the code.But why I am getting a ...
0
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1answer
52 views

Recommended literature to learn essential aspects of signals and its propagation [closed]

Where can I learn about signal's features. For instance mean, power, amplitude, frequency, energy, how they propagate in space or any other medium?. What power means its amplitude increases and ...
-1
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1answer
24 views

Output eqaution of a repeater?

Assume we have a signal repeater, a simple repeater that amplifies the signal then transmits it as is. Does the output power of the repeater is dependent on the received signal at the repeater ? for ...
0
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1answer
53 views

Is this a power signal?

$x[n]=\sin(\pi n)$ Since this is a discrete signal, and n can take only values like ...,1,2,3 ... the value of the power is getting zero, and since it gets zero does it mean that it's not a power ...
2
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1answer
2k views

variance in the time domain versus variance in frequency domain

Hi All: I'm trying to better understand the connection between variance of a time series and the integral of the spectral density over all frequencies. Rather than going through all of the relations, ...
0
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1answer
83 views

How to add awgn noise to a signal in Fourier domain for given SNR

I want to know the equations required to add awgn noise to a signal in Fourier domain for different SNR values. I know the procedure in time domain but not able to do the same in frequency domain for ...
3
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3answers
148 views

formula derivation for periodic signal power

Studying DSP on my own. Taking an introductory class. Was given a formula for signal power $$ P = \lim_{M\to\infty} {\frac{1}{2M+1} \sum_{n=-M}^M} \lvert x[n] \rvert^2 $$ I do understand why the ...
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2answers
590 views

Definition of average power?

There are two kind of average power I encountered in random signal class and textbook: definition 1: average power =$$E[|x(t)|^2]=R_{xx}(0)=\int^\infty_{-\infty} S_{xx}(f)\,df$$ definition 2: average ...
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2answers
34 views

Limiting bandwidth by adjusting sample rate

I have an SDR that is capabple of 2.4Ms/s. I am using it to measure the power of signals. Right now I am setting the sample rate to 2M, collecting a burst of samples, and calculating the average ...
1
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1answer
287 views

Why does increasing FFT length (narrowing bandwidth) not decrease Noise Power per bin?

I was under the impression that zero-mean white guassian noise had a constant Power Spectral Density which means that smaller bandwidths should decrease the power in that band. I'm getting surprising ...
0
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1answer
60 views

Product of power signal and energy signal

I tend to believe that if we multiply an energy signal with a power signal the product is an energy signal. My reasoning is that the energy signal will have finite bandwidth and consequenty the ...
6
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4answers
3k views

Is dirac delta (impulse) signal, a power or energy signal?

I'm a beginner so sorry if this question is very fundamental. Dirac impulse has finite area i.e = 1. But I've heard that $|\delta(t)|^2$ is undefined. So area under $|\delta(t)|^2$ is also undefined ...
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0answers
34 views

Multitapering in time domain to obtain smoother filtered signals?

Suppose we want to approximate the instantaneous power $z(n) = |y(n)|^2$ of the discrete-time signal $y(n)$, where $y(n)$ is the result of filtering $x(n)$ with a given window $h(n)$, $y(n) = x(n) \...
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3answers
1k views

Random signals as power signals

Why are random signals considered as power signals (i.e. signals with infinite energy and finite average power)? Does this make any sense? What does it mean for random signals to have infinite energy ...
0
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0answers
187 views

Power or Energy Signal doubt

I have to determine whether sin((n*π)/6) is a power or energy signal. This is the answer given in my textbook: How did they declare that ((-cos((n*π)/3))/2) is equal to 1? @Matt This is that ...
2
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1answer
699 views

Signal to Quantization Noise Ratio (SQNR)

I have this problem in my homework (following picture). How do find the signal to quantization noise ratio at the output? I don't want the solution. I just want to know a better approach to tackle ...
0
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1answer
39 views

What is full AM used for?

What are some applications where full AM is used nowadays? Is it used at all considering the fact that it is less power-efficient than, say, AM with suppressed carrier?
0
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1answer
73 views

find power of the signal

I have this signal: $$x(t)=\sum \mathrm{rect}\left(\frac {t-kT_0} {20}\right)+\mathrm{rect}\left(\frac {t-kT_0} {40}\right)+\mathrm{rect}\left(\frac {t-kT_0} {80}\right)$$ with $T_0=140$, pass it ...
2
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1answer
8k views

Calculate the signal's average power

We have this signal: $$x(t)= 2 + 2\cos(2\pi f_0 t) + \frac{2}{T_0} \operatorname{sinc}\left(\frac{2 t}{T_0}\right)e^{j2 \pi 4/ T_0} + \operatorname{sinc}\left(\frac{2 t}{T_0}\right)e^{-j2 \pi 4/ T_0}....
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0answers
39 views

Frequencies with the highest change in power over time

I am analyzing a time series data obtained from a vibration sensor. The signal is sampled at 5000 Hz. If I want to find out the frequencies at which the power of the signal changes the most over time, ...
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0answers
88 views

Two examples with power of periodic discrete signals? (had to repost)

Find power of the following periodic discrete signals: $x_1(n) = \sin(n\pi)$ $x_2(n) = \displaystyle\sum_{k=-\infty}^\infty \delta(n-5k)$ Also if possible, can you identify if $x_3(...
1
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1answer
267 views

Correlation between amplitude and power

In this link on page 218, just before the first paragraph ends, it says: " We can interpret the power axes as one-half the square [...] of the modulus of the complex envelope." In the same ...
2
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1answer
2k views

How can I calculate the amplitude of a signal from its power in dBm?

$$\begin{align} P_\text{out} &= 51.787\text{dBm}\\ P_\text{out} &= 10\log_{10}\frac{A_\text{out}^2}2\\ A_\text{out} &= \sqrt 2 \cdot 10^{\frac{P_\text{out}}{20}}\\ &= 549.3701 \end{...
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1answer
1k views

How to segment frequency bands after FFT and calculate power?

I have been working with EEG signal. I have raw EEG data for a 2-second (i.e. $t=2$) duration. My objectives are: Transforming these raw data from time domain to frequency domain. Segmentation into ...
0
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1answer
109 views

Power and Energy spectral densities of a linear system

Here is a schematic of my desired circuit. I want to calculate Power and Energy that the load dissipates during 0< t<8 You can see my attempts: Therefore How can find load's energy in ...
6
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2answers
312 views

Power of a periodic sequence

I am trying to find the way to reduce the standard expression to compute the power of a generic sequence $x(n)$: $$P_{\text{x}}= \lim\limits_{N \to \infty}\frac{1}{2N + 1}\sum\limits_{n=-N}^{N}|x(n)|^...
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3answers
3k views

Significance of energy and power signals in real world

In signals and systems subject we study about calculating energy and power of a signal, but what is their practical significance. Also what is the significance of a signal which is neither energy nor ...
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0answers
63 views

Is this a universal relation between signal power and period (frequency)?

I am Fourier analyzing at a bunch of signals of equal length and find that $$\frac{d\ln({E[P]})}{d\ln({PT'})}$$ is constant across the dataset, where $T$ is a vector of the periods (inverse of ...