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Questions tagged [signal-power]

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0
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1answer
33 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
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1answer
62 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
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1answer
36 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 ...
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1answer
33 views

Wireless Communication

Let's assume I send [\delta (t)] 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 components(due to ...
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0answers
24 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 ...
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0answers
25 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 ...
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0answers
17 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
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1answer
41 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 ...
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1answer
25 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 ...
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0answers
55 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 ...
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0answers
147 views

About the variance of the white noise process

I saw such an example in a book. Assume that the $w(t)$ is a white Gaussian noise with zero-mean and power spectrum density $N_0/2$. Now, consider the sample function: $$n(t)=\sqrt{2\over T}\int_{...
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0answers
35 views

Attempting to remove the 60Hz frequency out of a noisy ECG signal

load eeg_plus_noise Fs=200; Fn=Fs/2; b = fir1(64,[59.8 60.2]/Fn,'stop'); figure(3) freqz(b,1,512,Fs); y = filter(b,1,eeg_plus_noise); I am then using the ...
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0answers
28 views

What is wrong with my PSD computation?

I'm trying to calibrate the RX of my SDR Board to become a measuring receiver. I.e, by connecting it to a known source of power (in my case, a frequency generator), at a fixed frequency, I'm trying to ...
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0answers
11 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
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1answer
51 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
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1answer
26 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....
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2answers
53 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
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1answer
29 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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1answer
104 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
32 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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2answers
152 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
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0answers
36 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
31 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
162 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
262 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
37 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 ...
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1answer
1k 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
134 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
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1answer
614 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
41 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
848 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) ...
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1answer
141 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
57 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
55 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 ...
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1answer
33 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
58 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
3k 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
121 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
238 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
1k 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
36 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
404 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
80 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 ...
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4answers
4k 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
35 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 ...
2
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1answer
810 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
78 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
12k 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}....