# Questions tagged [signal-power]

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### 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.
676 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 ...
30 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 ...
71 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 ...
35 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'...
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### 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 ...
47 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 $|x_n|^2$ ...
63 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 ...
71 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 ...
52 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: ...
54 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 ...
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?
140 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 $S_x(f)$ ?
90 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 ...
55 views

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

Sampling the signalN 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) – ...
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### 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 ...
40 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 ...
43 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 ...
41 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 ...
37 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 ...
19 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 ...
161 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 ...
40 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 ...
111 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 ...
383 views

566 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 ...
340 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.
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### 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 ...
3k 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 ...
202 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: ...
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 ...
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### 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 --- ...
1k 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) ...
217 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 ...
59 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 ...
56 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 ...
$x[n]=\sin(\pi n)$ 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 ...