Questions tagged [signal]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
-1 votes
0 answers
26 views

Phase shift in Fourier transform

Suppose we have a signal x(t). If we Fourier transform the signal to the frequency domain we get a complex function (has js in it). Do the js mean a phase shift and what does phase shift in a Fourier ...
user avatar
0 votes
0 answers
14 views

Fourier analysis of delta function

I have this periodic function: $f(t) =\delta(t)+ \sum_{n=1}^{\infty }\delta (t-n)+\delta (t+n)$ and I need to find its harmonics by finding the coefficients for the Fourier series. But how is this ...
user avatar
1 vote
1 answer
36 views

Finding a signal output $y(n)$ with input signal $x(n)$ and impulse response $h(n)$ with a DTFT

I am studying for my Digital Signal Processing course and I am stucking on the following exercise: Given an $\text{LTI}$-system with input signal $$x(n)=\frac{1}{4^n}u(n)$$ and impulse response $$h(n)...
user avatar
0 votes
0 answers
21 views

How to send a TTL trigger signal remotely

Sorry if this is a dumb question, but I am an undergrad intern working on a semi-independent project in a lab, and no one here can really help me with this. I am trying to control a lab instrument ...
user avatar
0 votes
0 answers
6 views

Attenuation along microstrip

I just wanted to know why signal attenuation decreases with length across a micro strip transmission line. Isn't it meant to decrease but experiments show otherwise.
user avatar
  • 1
0 votes
0 answers
7 views

NFC chip to directly compare sent to stored value

I had an idea for an application using NFC chips / tags. The idea would require me to store a value on the chip. Later, during usage, an active device like a phone should send a value and the NFC chip ...
user avatar
2 votes
0 answers
27 views

When working with generic electrically shielded signal cable, can I treat the unshielded strands of wire as signal reference ground?

I am working on a CNC application where one controller board will be sending signals to another board. The environment may have electromagnetic interference (EMI) from nearby motor activity, so these ...
user avatar
0 votes
0 answers
23 views

Loss due of traversing a material

I would like to know how to calculate losses due of different materials at UHF frequencies (e.g., 865MHz, 910MHz). The path loss could be computed with formula: $$L=20\log_{10}\left(\frac{4\pi d}{\...
user avatar
0 votes
1 answer
72 views

How significant is signal noise from a BNC connector?

I'm trying to build a double cross antenna that can be folded/taken apart based on the design of the picture and receive signals from weather satellites. The idea is to make each of the four dipoles ...
user avatar
2 votes
1 answer
91 views

Active noise cancelling headphones - How fast does a digital signal processor have to be to perfectly cancel out noise with an inverted signal?

How fast does a digital signal processor have to be to perfectly cancel out noise with an inverted signal? Is it possible for a digital signal processor react so fast?
user avatar
1 vote
1 answer
148 views

How to add a Gaussian noise signal with zero-mean in a given data set?

I have a real-time velocity measurement data set in a excel (.xlsx) file. I want to add the Gaussian noise signal with zero mean in this real-time data to create three set of pseudo measurements. ...
user avatar
0 votes
1 answer
63 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 ...
user avatar
  • 1
0 votes
0 answers
46 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; $H[z]=\frac{Y[z]}{X[z]}$ $H[z]=1+0.8z^\frac{-1}{5}$ ...
user avatar
0 votes
2 answers
75 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 ...
user avatar
  • 141
1 vote
1 answer
42 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 ...
user avatar
0 votes
0 answers
23 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 ...
user avatar
-1 votes
1 answer
29 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 ...
user avatar
1 vote
0 answers
24 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 ...
user avatar
1 vote
1 answer
22 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}(\...
user avatar
0 votes
1 answer
154 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.
user avatar
1 vote
0 answers
33 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 ...
user avatar
2 votes
0 answers
81 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 ...
user avatar
1 vote
0 answers
31 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 ...
user avatar
  • 161
1 vote
2 answers
79 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 ...
user avatar
0 votes
2 answers
82 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 ...
user avatar
1 vote
0 answers
89 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 ≤ ...
user avatar
  • 11
2 votes
1 answer
205 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 ...
user avatar
  • 21
4 votes
2 answers
125 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 ...
user avatar
10 votes
1 answer
639 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 $H$: $$H(\omega) = \frac{V_{out}(\omega)}{V_{in}(\omega)}$$ ...
user avatar
16 votes
3 answers
48k 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 ...
user avatar
  • 489
3 votes
1 answer
989 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 ...
user avatar
  • 31
7 votes
0 answers
553 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 ...
user avatar
  • 81
2 votes
1 answer
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(...
user avatar
  • 23
8 votes
1 answer
204 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) = (...
user avatar
4 votes
2 answers
298 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: (...
user avatar
10 votes
4 answers
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 ...
user avatar
  • 203
8 votes
1 answer
204 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 ...
user avatar
  • 183
4 votes
0 answers
102 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. ...
user avatar