Questions tagged [signal-power]
192 questions
9
votes
3 answers
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 power signal ?
Patrick
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5
votes
1 answer
How can I calculate the amplitude of a signal from its power in dBm?
$$\begin{align}
P_\text{out} &= 51.787\text{dBm}\\
P_\text{out} &= 10\log_{10}\frac{A_\text{out}^2}2\\
A_\text{out} &= \sqrt 2 \cdot 10^{\frac{P_\text{out}}{20}}\\
&= 549.3701
\end{align}$$
Is this calculation correct to yield the amplitude of my…
user25356
2
votes
2 answers
Power of a real exponential signal
I am having difficulty with the case when a is real.
But after this, I am not going anywhere.
Anwesa Roy
- 21
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2
votes
1 answer
Several questions about power of periodic signal
I am currently learning Fourier series (periodic signals) and there are few things I am not sure about.
(1)
$$
P = \frac{1}{T}\int_{-T/2}^{T/2}|s(t)|^2dt = \frac{1}{T}\int_{0}^{T}|s(t)|^2dt
$$
Let's say, that period is $T = 2$ and my signal $s(t) =…
Michal
- 21
- 1
1
vote
1 answer
How to determine the power of a finite signal?
I am trying to write mathematically how to calculate the power of a finite signal. I know the general formula $P_{\mathrm{x}}=\lim_{T\to\infty} \frac{1}{T} \int_{t=0}^{T} x^{2}(t) \mathrm{d} t$ used to calculate the power of a signal which has…
Shkodrani
- 87
- 4
1
vote
1 answer
Tx power vs Error Vector Magnitude
I cannot tell how decrease/increase in Tx output power should impact EVM?
What is the mathematical relation of I,0 values on the constellation map and output power?
in the context of 802.11, I am trying to understand what is the limiting factor of…
Nir Barsheshet
- 11
- 1
1
vote
2 answers
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 power using
10 * log10(sum(abs(sample)**2 for sample…
Ken - Enough about Monica
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- 20
1
vote
1 answer
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 paragraph, the average input power is stated to be…
user25356
0
votes
1 answer
How to measure signal PAR (PAPR) in practice?
Let's consider baseband complex signal like this:
red: real part of signal
blue: magnitude^2
green: mean value of magnitude^2
as you can see, there are a lot of peaks but only one has value greater than 10. From definition PAR=Ppeak/Pmean...…
Andrew123
- 123
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0
votes
2 answers
Signal power normalization
Let's say a I have a signal
x= [1,2,3,4,5,6,7,8,9,10,11]
y= [0, 2, 4, 6, 8, 10, 8, 6, 4, 2, 0]
How do I normalize this signal so the integral from 0 to 10 (along x-axis) would give me 1? Meaning the total power of the signal will be 1 after…
MRR
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0
votes
1 answer
Signal Power estimation
I want to add a White Gaussian noise to noise-free signal given desired SNR value. To do that, I am looking for a way to estimate the power of the signal. The noise-free signal looks like the following:
Do you have any clue about how to estimate…
akho
- 11
- 1
0
votes
1 answer
Average power of finite length discrete signal
I know that the power of a discrete signal is given by:
$$P(x) = \lim_{N \rightarrow \infty}\frac{1}{2N + 1}\sum ^N _{n = -N} | x[n]|^2$$
However, I would like to know whether the power of a discrite time finite length signal is defined as:
$$P(x) =…
DaDSPGuy
- 182
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0
votes
1 answer
AM-AM plot (input power vs output power) for power amplifier
I have modelled a power amplifier using weiner's model in matlab.
But when I finally plotted the input vs output power plot I got a plot that grows linear , then reaches maxima and then starts falling. As far as I know it should saturate after…
Hitman 47
- 11
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0
votes
2 answers
Why the "20" in calculating db ratio?
In wikipedia, I read the formula to convert a power ratio to db. This formula is :
10*Math.log10(power_out / power_in);
But, for the sound pressure, I read the formula is :
20*Math.log10(soundLevel_out / soundLevel_in);
I read in some places a…
Dr_Click
- 161
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0
votes
1 answer
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 different answer for the power?
x=[1 2 3 4…
anil
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