Questions tagged [signal]

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55 views

Is it possible that room noises could end up on the recording when recording audio from an analogue source?

I have a VCR with a tape cartridge playing in it. The video output (SCART/RCA) goes from the back of the VCR into my Elgato video capturing device's RCA cables. The Elgato device is then connected via ...
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0answers
40 views

How can I find the Transfer Function in Z-domain?

This is my signal; $y[n]=x[n]+0.8x[n-0.2]$ When I take Z-transform I get; $Y[z]=X[z]+0.8z^\frac{-1}{5}X[z])$ Then I found the Transfer function as; $H[z]=\frac{Y[z]}{X[z]}$ $H[z]=1+0.8z^\frac{-1}{5}$ ...
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0answers
14 views

How is MRI SNR affected by the frequencies that are included?

So for MRI imaging, if an image is taken, and portions of the Fourier transform image are removed so that some portion of the higher frequencies are not included, would this reduce the SNR? I assume ...
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2answers
63 views

Are there offsets in these accelerometers signals?

How you can see in the picture below, there are 3 signals from 3 piezo accelerometers placed on a oscillating 3D structure. The structure should vibrate only along the z axis (blue track), but there ...
1
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1answer
41 views

Quickly stopping a phone from attaching to a network

I struggled for a while to find which group I might ask this question in. Figured engineering minds would be the best. Some time ago I discovered a good friend was in an abusive relationship. This ...
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0answers
18 views

Can cross correlation be used to see if filtering of a signal has changed it too much?

I am filtering a signal, and want to check if I am not over filtering it , I wanted to use cross correlation , but I am not sure if it is a good technique. usually I get something like the following ...
-1
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1answer
28 views

Small wireless proximity device to alert me when my cat gets into my WiFi range

I have the following situation. My cat goes outside every day, the problem is I have no way of telling when he is back around the house unless I go outside myself. I need some small wireless device I ...
1
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0answers
21 views

Meaning of SNR in Instrument Specifications

I am evaluating the specifications of an FTIR instrument (Bruker Vertex) and came across the following statements/items: Signal-to-Noise 5 sec sample, 5 sec reference: >10,000:1 (<4.34 x 10-5 ...
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1answer
16 views

How does free space path loss change with receiver's antenna's height

I have a question which seems like an easy one, but I couldn't find anything on Internet to be 100% sure. The free space path loss equation is: $$FSPL=20\text{log}(d)+20\text{log}(f)+20\text{log}(\...
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1answer
87 views

How to read the block diagram for the 2nd order integrator feedback system?

This is a prework for a lab, I haven't seen things in the picture before and have no idea on how to transfer this to an equation.
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0answers
30 views

How can I measure the impact of noise on a FFT?

Please, I have to solve a problem and I really need some help. I have to give an efficient method to consider a maximum amplitude as a starting point to consider as noise the whole spectrum below ...
2
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0answers
80 views

How do mobile phones switch 4G/3G/2G?

I would like to know the algorithm of switching between 4g/3g/2g. When will the phone switch from 4G to 3G or from 3G to 2G, when we select for corresponding option in the mobile phone. Is it based on ...
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0answers
29 views

How to determine data size created by sensor for calculation of signal processing and transmitting over wireless communication?

I want to build some sort of SAR sensor. Since radar works high speeds and creates loads of data this should be processed faster. I am trying to find algorithms to be used for this purpose. I am at ...
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2answers
76 views

Filtering Long-duration Signal

I have a long-duration EMG signal (~4 hours long) with a sampling frequency of 1 kHz. If I want to filter the data with a low-pass filter in 10 Hz in MATLAB, should I filter the signal with ...
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2answers
72 views

Center line of cut-off periodic signal

What I am after is the center line of this wave, which is 0. How can I calculate that value though? For example, run the code below for a simple example in Matlab. This will plot a simple sine wave ...
1
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0answers
88 views

Signals and systems convolution problem? [closed]

hey guys I'm having trouble with a convolution problem here A continuous-time linear system has the input/output relationship $$\int_{-\infty}^t (t-\lambda-2) x(\lambda) d{\lambda}$$ For $1 ≤ t ≤ ...
2
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1answer
197 views

Hilbert transform LTI

I'm studying the Hilbert transform and its properties. I found out that Hilbert transform can be considered as a linear time-invariant system. How can I show this? I guess this should be trivial as ...
4
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2answers
108 views

Finding the sampling period to avoid loss of signal

We have: $$ s(t) = 4u(t)−u(t−1)−2u(t−2)−2u(t−3.5)+2u(t−4) $$ where $u$ is the Heaviside function. I had to draw the graph and find the minimum sampling period so we wont have loss of signal. I have ...
10
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1answer
576 views

Response of a system to a step function (Heaviside function)

I'd like to compute the response to a step function of a electrical/thermal system. Generally I can "easily" compute the transfer function $H$: $$H(\omega) = \frac{V_{out}(\omega)}{V_{in}(\omega)}$$ ...
16
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3answers
45k views

Can wifi signal reception be improved by opening a door?

A wifi user is in a different room than the router. The computer is having a hard time connecting and receiving the wifi signal. Can the wifi signal from the router to the computer be improved by ...
3
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1answer
928 views

signal-to-interference-plus-noise ratio (SINR) and others calculation

I am considering some empirical signal propagation models (like Hata, Ericsson models) to calculate 4 parameters: Path loss Received Signal Strength (RSS) signal-to-interference-plus-noise ratio ...
7
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0answers
529 views

BER peroformance of MPSK and MQAM in Rayleigh fading channel

I have a question regarding bit error rate (BER) performance over the Rayleigh channel. I observed BER performance over the AWGN channel using Simulink in MATLAB. I used to change the "SNR" parameter ...
2
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1answer
2k views

What kind of signal is the signum function? A power signal or an energy signal?

I'm studying "signals and systems". We can indentify two kinds of signals: power signal and energy signal. The definitions are: Energy of a time-continous signal $$ E_x = \int_{-\infty}^{+\infty}{|x(...
8
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1answer
196 views

What are the meanings of the second argument to the convolution?

I was trying to understand the convolution better and its mathematical properties and interpretations in engineering (specially in the context of computer vision). Recall the convolution: $$ s(t) = (...
4
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2answers
281 views

What is a “window of length N” in a signal processing algorithm?

I am reading a scientific paper in which an algorithm for evaluating an electromyography signal is described and I just don't get the meaning of the word "window" in the following part of a sentence: (...
10
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4answers
12k views

Is it possible to “boost” a WiFi signal using an aluminum soda can?

I recently discovered that one of my roommates had attempted to boost the WiFi signal by cutting up a soda can and placing it near the router, like this: My roommate was probably following an ...
8
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1answer
197 views

Best way to send a signal in a very low frequency (250Hz)?

I am a programmer facing an electronic question, so I thought here is the place to ask! I have a magnetic field sensor which provides me with magnetic field values (XYZ axis) 250 times a second. An ...
4
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0answers
97 views

Implications of concatenating EEG signals

I am wondering about the mathematical implications of concatenating very small windows from different trials. All of the trials are the same size, and are for the same period of time after a stimuli. ...