Questions tagged [signal-power]
The signal-power tag has no usage guidance.
188
questions
0
votes
2
answers
22
views
What is the difference of calculating signal power that using these two methods: using moving average filter and using forgetting factor?
The conventional signal power calculation can be:
$$
P(n) = \frac{1}{N}\sum_{i=0}^{N-1}x^2(n-i)
$$
$x(n)$ is the signal. However, I have seen another method:
$$
P(n) = \lambda P(n-1) + (1-\lambda) x^2(...
- 1
0
votes
0
answers
15
views
How to impose power constraint on an encoder's output while training a deep NN?
A deep encoder which takes in a 4 bit input gives out an 8-dimensional vector. If I want the power of this 8-D vector constrained to be 1, then I should multiply all the elements by A/B? Where A is ...
0
votes
0
answers
24
views
EIRP for JWST HGA
I am attempting to compute the EIRP for transmissions from the James Webb Space Telescope using the high-gain antenna. I found the following reference...
https://www.ioag.org/Public%20Documents/2019-...
- 63
0
votes
0
answers
14
views
Computing Channel Power from file containing RMS measurements from tri-axial spectrum analyzer
I have some files from a spectrum analyzer in RMS mode equipped with a tri-axial antenna. I am supposed to compute the channel power evolution for two distinct LTE channels.
I have files containing ...
- 63
0
votes
1
answer
66
views
Energy and power of time-continous signal $x(t)=t$?
Preparing for my exams, I stumbled upon this particular problem.
I tried to calculate it using following formulae:
$$ E = \int_{-\infty}^{\infty}|t|^2dt $$
Dividing it into two cases because of the ...
- 13
2
votes
1
answer
311
views
Can the total energy of a signal diverge while its average power converges to zero?
If the integral used to calculate the total energy for a continuous time real signal converges, its average power is equal to zero. But could the average power still equal zero if the total energy ...
2
votes
1
answer
49
views
Why a windowed signal is considered to evaluate the Power Spectral Density?
Let's consider a real function of time $x(t)$ being a Fourier-transformable signal. The synthesis equation states that:
$$x(t)=∫_{-∞}^{+∞}X(f)⋅e^{2πjft} df $$
Meaning: $x(t)$ can be seen as the sum of ...
- 324
1
vote
0
answers
54
views
Sinus Pattern analysis
i have 1000 data which range between 50 and 180 ( heart BPM data in a day) how can i measure its similarity to a Sinus pattern?
for example, for 20th recorded data (for example it is 60BPM), evaluate ...
0
votes
1
answer
47
views
Why is power level area under the autocorrelation function of the white-noise signal?
A paper I am reading (Linear and Nonlinear Encoding Properties of an Identified Mechanoreceptor on the Fly Wing Measured with Mechanical Noise Stimuli) defines power level for a white-noise signal as ...
2
votes
0
answers
37
views
Average time-domain signal power from correlated Fourier transforms
Suppose I have real-valued continuous-time sequences $x_1(t), x_2(t), x_3(t)$ with Fourier transforms $X_1(\omega), X_2(\omega), X_3(\omega)$. I know that $X_3(\omega)=H(\omega)( aX_1(\omega)+bX_2(\...
- 325
1
vote
0
answers
54
views
Incorrect Power Calculation in MATLAB Convolution
I have been working on a MATLAB code to perform convolution and calculate the power of the resulting signal. However, I have encountered an issue with the power calculation in my code.
I am convolving ...
- 11
0
votes
3
answers
194
views
Power / energy of complex signals - physical interpretation
I am wondering about physical interpretation of energy / power for complex signals. E.g. for signal energy definition:
\begin{equation}
E=\int\limits_{-\infty}^{\infty}|x(t)|^2 \, \mathrm{d}t
\end{...
- 1
2
votes
1
answer
436
views
How is the PSD the Fourier Transform of the Autocorrelation function?
I am getting very confused with the textbook I am reading through: Modern Digital and Analogue Communication Systems:
3.8.1 Parseval's Theorem says that:
The total power in a power signal is its time ...
- 33
0
votes
1
answer
156
views
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 ...
- 123
0
votes
1
answer
163
views
How to calculate to power of a uniformly distributed noise?
I was wondering how I would calculate the power of a noise, if I have a uniformly distributed white noise between $-\frac{q}{2}$ and $\frac{q}{2}$? My approach was to use the formula
$$\int\limits_{-\...
- 3
0
votes
0
answers
50
views
How to measure the PAPR of OFDM signal in practical case
The way of investigating the PAPR for OFDM system using MATLAB is known, but what I am looking for is: can we measure the PAPR effect in real systems?
For example, assuming we have a transmitter and a ...
- 598
2
votes
0
answers
40
views
Why am I not getting proper values of power(Px) and energy(Ex) signal as per book?
I am considering an energy signal in MATLAB as I am going through the book Signals and Systems Laboratory with MATLAB by Alex Palamides.
My Matlab code is below:
...
- 21
1
vote
2
answers
296
views
Is there instantaneous energy for signals? Why is $\big|x(t)\big|^2$ instantaneous power?
Today I learned, instantaneous power is
$$
p_x(t) = |x(t)|^2
$$
and I've known, energy is
$$
E_x = \int_{-\infty}^{\infty} |x(t)|^2 dt
$$
What I also thought was, $|x(t)|^2$ is instantaneous energy, ...
- 8,815
2
votes
1
answer
505
views
Definitions of Discrete Power Spectrum and Discrete Power Spectral Density
I have been reading lots of posts about the scaling factors in PSD, and related topics on this forum. My understanding of the topic has been greatly improved. Thankyou all. I just need a little more ...
- 37
0
votes
1
answer
65
views
Bartlett's method: Order of normalisation?
I want to estimate the power spectrum of a given signal using Bartlett's method.
I understand the general purpose of the method. However, I do not get my head around the algorithmic description of the ...
- 109
1
vote
3
answers
226
views
Minimal SNR to distinguish LFM target from noise at range doppler output
I am working on a radar signal processing project using MATLAB. I am required to simulate range doppler maps for Linear Frequency-Modulation (LFM) targets (non-fluctuating) in noise at various SNRs (...
- 11
1
vote
1
answer
224
views
Calculating SNR of one N-point DFT over another M-point DFT in frequency domain
Consider N-point sine signal mixed with a random noise (implemented in Python below):
...
- 355
0
votes
1
answer
80
views
signal power from single sided DFT
Definitions
As far as I know the power of a signal can be expressed (using discrete time samples) via:
$$
P_x=\frac{1}{N}\sum_{n=0}^{N-1}\big|x[n]\big|^2
$$
For details see this question.
However, it ...
- 293
-2
votes
1
answer
110
views
Energy ratio of signal
What is the energy ratio of signal at frequency domain?
What is its mathematical formula at frequency domain and what can stand for?
I found it in this paper
https://www.researchgate.net/publication/...
- 43
1
vote
6
answers
953
views
What's the meaning of negative frequencies after taking the FFT in practice?
Suppose I have a signal $x(t)$ with baseband bandwidth $W$ Hz and power $P$, and consists of $K$ samples, and I draw the two-sided power spectral density (PSD) of this [baseband] signal in MATLAB as
<...
- 131
0
votes
1
answer
10
views
Knowing the power of a portion of a signal's spectrum inside another signal's spectrum
I have a signal $x_1(t)$ with baseband bandwidth $W_1$ Hz over a carrier frequency $f_1$ and power $P_1$. I also have another signal $x_2(t)$ of baseband bandwidth $W_2$ Hz over a carrier frequency $...
- 131
1
vote
3
answers
196
views
energy or power of exponential summation signal
Determine below signal is power or energy and derive its power or
energy accordingly. $$x(t)=\sum_{n=-\infty }^\infty e^{-\lvert
t-n\rvert } \tag 1$$
we have :
$$E_x=\int_{-\infty}^{\infty}(\sum_{n=...
1
vote
1
answer
166
views
Noise with a positive or negative mean
I am working on calculating the SNR for my network model.
Considering AWGN at the receiver with zero means, the SNR can be presented as
$$\text{SNR} = \cfrac{P \cdot|h|^2}{\sigma ^2}$$ where $P$ and $...
- 11
0
votes
2
answers
842
views
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-...
- 25
0
votes
0
answers
23
views
Normalized Power of a signal [duplicate]
I have the following power values in Watts of a signal:
6.5e-8, 4.6e-8, 7.1e-8, 1.01e-7, 9.98e-7, 2.5e-6, 3.96e-6, 2.84e-5, 2e-4, 4.05e-4, 1.7e-6, 8e-7, 8.23e-8, 8.32e-8.
How do I normalize this to ...
- 25
1
vote
0
answers
64
views
Understanding the following formula of Throughput?
In massive multiple input multiple output (MIMO) case, I came across the following formula of throughput:
$\tau_{ij} = \bigl[\displaystyle\sum_{j\in \mathcal{U}}x_{ij}\bigr]^{-1}W_i\text{log}(1+\...
- 37
2
votes
2
answers
263
views
SNR ratio in radar for stationary targets
Is there a mathematical model which provides relationship between the Signal to Noise Ratio in radar measurements and velocity/range of targets. i.e.
How SNR varies with the speed of targets?
How SNR ...
- 163
-1
votes
2
answers
322
views
Elevation angle or Azimuth angle?
Suppose my ULA(Uniform Linear Array) is along x-axis only, then definitely we can estimate elevation angle with this ULA. But if we lift this array from x-axis and place it along y-axis, then which ...
0
votes
0
answers
93
views
What is physical significance of Bit Error Rate (BER) and Outage Probability?
I am trying to understand the physical significance of Bit Error Rate (BER) and Outage Probability especially in low power wireless communication such as internet of things (IoT).
Any help in this ...
- 37
3
votes
1
answer
145
views
Finding a periodic signal knowing its period, mean value and power
I've found an interesting exercise which I have been trying to solve for a couple days, without success.
Let $x(t) \in \mathbb{R}$ be a periodic signal with fundamental period $T_0 = \tfrac{1}{4}$, ...
- 33
0
votes
0
answers
18
views
Noise impact on X-band signal amplification
I have a locally generated 10 GHz LO signal that should go into the LO port of a mixer. The LO signal strength is -1.7 dBm. The mixer has a required LO-drive of about 13 dBm. Before the LO signal hits ...
- 3
2
votes
1
answer
316
views
Power of noise signal through a matched filter (Digital Receiver)
I am studying matched filters and the sense of signal to noise ratio. In a question I was given, stated that:
Show that a matched filter of a signal $s(t)$ maximizes the SNR of the
output on a ...
1
vote
0
answers
54
views
Envelope of a series of pulsed signals [duplicate]
I need to record a series of pulse waves for an experiment. The recording is done via Software Defined Radio (GNU Radio). The pulse waves are modulated in such a way that the amplitudes of each single ...
- 11
1
vote
0
answers
28
views
Is there a standardize method for writing statements combinations of (RF) signal flow path through a system?
Let's say I am given a system block diagram of various components that either route/switch/amplify/filter and so on. Each of these components of the system perform these signal modifications or lack ...
2
votes
1
answer
323
views
What a SDR can (and cannot) tell about a received signal's power/energy
I'm rather new to SDR and I'm still wrapping my head around understanding how it functions. I greatly appreciate it if you guys can help me understand what's going on.
From what I've gathered, an SDR ...
- 23
4
votes
3
answers
366
views
Undestanding antenna gain applicability
While searching for the info about antenna gain and why it is GAIN I found this interesting example:
If the two antennas in the drawing are “welded” together, how much power will be measured at point
...
- 63
1
vote
1
answer
174
views
Power of signal in specific frequency in FM and AM modulation
My professor gave us the following problem:
Given a sinusoidal signal with $f_m = 1KHz$ which is put into an AM
and FM modulation find the modulation index of FM and AM if you know
that (amongst ...
0
votes
1
answer
91
views
Power Spectrum for feature extraction
I want to extract frequency domain features for my machine learning model, and to do so I have calculated the power spectrum of the EMG signal. One of my first questions is that my frequency is just ...
- 3
0
votes
0
answers
53
views
What are the differences between GPS and GLONASS?
I'm studying the localization systems, especially the GPS one. I inquired about other systems and wanted to understand what are the main differences between GPS and GLONASS, why has the first type ...
0
votes
1
answer
460
views
How can I add white gaussian noise to get the required extinction ratio?
I need to add white gaussian noise to my signal in MATLAB so that I obtain 15 dB extinction ratio (ER). I know that ER is max power level to min power level. I use below code to calculate my signal ...
- 53
0
votes
1
answer
326
views
Plot the Power Spectral Density for a signal in Matlab
I have an OFDM signal x, generated using QAM modulation, I first use the command in matlab y1 = ifft(x); to generate the time-...
- 165
0
votes
1
answer
218
views
number of subcarrier and transmit power
How does the total transmit power affects the number of subcarriers?
For example, if we have 624 subcarrier, can we use the same maximum power (for example the budget is 64 watts) as we will when we ...
0
votes
1
answer
208
views
Calculating instantaneous power of a frequency band in a 1-d signal
I am trying to calculate the instantaneous power of a 1-d signal within a particular frequency band in an on-line, real-time, streaming application. I have tried using sliding window FFTs but these ...
0
votes
0
answers
56
views
Correct Noise for NOMA system
I am trying to simulate a NOMA system with SIC, but I'm so confusing with the noise expression: $n_m \sim CN(0, \sigma^2_m)$, is zero mean complex additive Gaussian noise with variance at mth user
...
1
vote
1
answer
27
views
How to find the relative energies between multiple frequency bands?
I am filtering my input into four frequency bands using IIR filters.
The output of each band has some disturbances or ripples in it. I am looking for a method to normalize the four bands so that all ...
- 121