Questions tagged [signal-power]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
5
votes
5answers
438 views

Inconsistency with the units of power spectral density and the definition the people often give

Perhaps someone can help me resolve something - this is my understanding: In deterministic signal analysis, for a signal $x(t)$ the signal energy (as opposed to the real physical energy) is given by $...
1
vote
1answer
59 views

dB SPL readings differ from external sound level meter?

I'm trying to write a program that takes values from a MEMS microphone and calculates the dB of the incoming audio data. The microphone i'm using is this: https://www.mouser.es/datasheet/2/218/...
0
votes
0answers
41 views

Calculation average signal power and Eb

I am working in a project and I would like to add noise to my received signal, but I would like to add the noise according to the value of $\sigma$, $$\sigma^2 = \frac{(1/No) \times sps \times Ps)} {...
0
votes
0answers
43 views

Calculating the power spectral density on a different bandwidth

Let us say I have the power spectral density for a given bandwidth F1 at a transmit power T. I would like to calculate the power spectral density for bandwidth F2 for 1) the same transmit power T 2) ...
0
votes
2answers
39 views

Channel noise - A misnomer?

I was discussing with a colleague with background in communication about white Gaussian (WG) channel noise. He said noise is not added by the channel and it's just a misnomer. Noise, which is thermal ...
0
votes
0answers
17 views

bit energy real values in wireless communications

I am wondering what will be the reali magnitude of $E_b$ in terms of dBm or watt? What is the range of bit energy values in real wireless communications? In terms of mWat or dBm? Thanks
0
votes
0answers
20 views

Calculating average power of a discrete random signal with complex values

I have a Rayleigh channel that transmits discrete values according to the following: $$y(n) = h(n) * s_n + \omega_n$$ Where $y$ is the received message, $s_n$ is the symbol sent (constellation 2-PSM), ...
0
votes
1answer
27 views

help with bandwidth diagrams for digital transmission

I am taking a undergrad network course that uses Data Communications and Networking 5th edition containing diagrams and legends which I cannot decipher. Specifically the diagram on the right, has y-...
0
votes
0answers
9 views

I don't know why the packet size is considered in this packet reception probability equation

https://www3.nd.edu/~mhaenggi/pubs/broadnets04.pdf In 3 page of this paper, the packet reception probability without interference is $e^{-\theta N Ad^2/ P}$. $\theta$ is sinr threshold. $N$ is a ...
-3
votes
1answer
18 views

average power of signal given the mean and the variance [closed]

Let a signal be a random process.Given the mean and variance what is the average power of the signal.
6
votes
4answers
716 views

What are the units of the product of two signals?

In a standard mixer, we multiply two signals $x_1(t)$ and $x_2(t)$, each with units of volts $(V)$, and get at the output: $$y(t)=x_1(t)\,\cdot\,x_2(t)$$ I have always thought that the output of ...
1
vote
1answer
36 views

Analytically determine a PSD from a transient function

This question is related to a series of questions I have asked about the units of PSD and ESDs. I include it as a separate question as it may have worth in isolation. As I understand it to compute ...
1
vote
2answers
74 views

The sum part of the formula for a signals power

$$P_x=\lim_{M\rightarrow \infty }\frac{1}{2M+1}\sum_{n=-M}^{M}\left | x[n] \right |^2$$ I have used this formula to find out the powers for different signals, but the sum part of the formula still ...
2
votes
1answer
38 views

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'...
1
vote
1answer
252 views

Scaling of the PWELCH function in MATLAB

I am trying to compute the power spectral density of a random signal using the PWELCH function in MATLAB. Since I think have not understood properly how Pwelch scales the PSD, I wrote a sample ...
0
votes
1answer
86 views

Coefficients of the Fourier Series expansion of physical signals having finite power

Question 2.7. Show that for all periodic physical signals that have finite power, the coefficients of the Fourier series expansion $ x_n $ tends to 0 as $ n \to \infty $ I have computed $ |x_n|^2 $ ...
0
votes
0answers
97 views

Signal Averaging

Note I also asked this in math stackexchange I was reading a wiki page about signal averaging specifically in the section Signal power for sampled signals. At least at first glance the information ...
1
vote
3answers
127 views

Power of summed signals

Pretty much a newbie here, but would like to understand a pretty basic concept. We all know that a quick and dirty way of calculating signal power of a part of a discrete sampled system (such as ...
0
votes
2answers
57 views

Is it valid to calculate the magnitude, power, and phase of a real time-domain signal without converting it to the frequency-domain?

I would assume you perform the calculations the same way, but since there would be no imaginary component because the signal is not complex it would be simpler: ...
1
vote
2answers
146 views

How to adjust receiver gains to avoid saturation and quantization noise to optimise post digital processing?

I am using a Hack RF One as SDR and the software GNU Radio to receive and process signals emitted from a drone. Given that the drone is moving and is emitting signals from a wide zone, received signal ...
0
votes
0answers
10 views

Is it possible to measure SINR at 802.11p using a received packet? How long will it take if possible?

When a node receives a packet, is it possible to measure SINR at 802.11p using the received packet? How long will it take if possible?
0
votes
1answer
220 views

Power contained in a random process $X(t)$

How do we calculate the AC and DC power of random process $X(t)$ , provided we have $R_x (\tau)$, and $S_x(f)$ ?
0
votes
2answers
143 views

PSD of modulated signal

I know this question has been previously asked just saw it and tried to do myself but reaching an expression which is different from expression of PSD which I remember for modulated signal Actual ...
0
votes
1answer
57 views

SNR contains $\log N$ term where $N$ stands for number of samples

Sampling the signal$ $N times increases the signal energy by a factor of $N^2$ and the noise energy by a factor of $N$. Why? This explanation is written for SNR(dB) = signal peak(dB) – ...
2
votes
1answer
87 views

What kind of power spectrum implies uncorrelation in time?

I am new in signal processing field, and actually I just need some basic tools for what I am working on. I've learnt that the autocorrelation function is the inverse Fourier transform of the signal's ...
0
votes
1answer
42 views

How to detect if a signal raises sharply or slowly?

so how can i detect if a signal raises sharply or not ? Are there easy solutions (i suppose there are) ? the problem is that if a signal raises sharply, i need less data to not pollute the dataset ...
0
votes
1answer
44 views

Wireless Communication

Let's assume I send a root raised cosine pulse of 1ns at t=0 through a wireless channel. The power measured @ Receiver from t=0 is shown in image. Now from this image, I know that there are multipath ...
0
votes
0answers
51 views

Binary vs 4-PAM PSD

I'm struggling to understand how you would form an expression for the PSD of a 4-PAM signal which is using rectangular pulse shaping. I understand for binary the likelihood of +/1 is equal so the ...
0
votes
0answers
44 views

Remove constant noise from Goertzel output

I'm trying to analyze a signal recorded from an analogue phone line and do DTMF recognition using a Goertzel algorithm. However, due to a fault in the hardware, there is a constant 50Hz power line ...
0
votes
0answers
23 views

Getting SNR of reconstructed signal in MATLAB

I am trying to run code to compare the efficiency of various basic sampling methods such as ideal sampling, natural sampling and so on. I want to then use average power to see how accurate the ...
0
votes
1answer
271 views

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 ...
1
vote
1answer
51 views

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 ...
1
vote
0answers
153 views

Power spectral density of a pulse

A little background: I am simulating the response of an antenna to a pulse. The pulse has a wide frequency range, but the antenna only responds to a fairly narrow frequency. I can extract voltage and ...
0
votes
0answers
21 views

Correct way to calibrate RX into a measuring receiver

While playing with my SDR (Software Defined Radio) Board, I was interested in performing a TX output power table at different center frequencies and TX antenna gains. I have an RF frequency generator....
0
votes
1answer
158 views

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 ...
0
votes
1answer
52 views

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....
0
votes
2answers
56 views

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 ...
0
votes
1answer
47 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 ...
1
vote
1answer
244 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
votes
1answer
45 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=\...
1
vote
2answers
575 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 ...
2
votes
0answers
39 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
votes
1answer
33 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
votes
1answer
814 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 ...
0
votes
3answers
379 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
votes
1answer
42 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 ...
2
votes
1answer
4k 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
votes
1answer
233 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: ...
0
votes
1answer
1k 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 ...
1
vote
0answers
43 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 --- ...