Questions tagged [signal-processing]

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89 votes
4 answers
47k views

Why do color TVs make black and white snow?

If you let a color TV display something from an unplugged display port, it displays snow, right? Randomly varying black or white pixels on the whole screen. My guess was that the television was ...
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12 votes
2 answers
578 views

Does a Faraday cage effectively act as a notch filter?

In reading about Faraday cages, I have found that most "real world" designs incorporate multiple layers of mesh. For example, this article from the National High Magnetic Field Lab discusses several ...
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10 votes
1 answer
643 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 $H$: $$H(\omega) = \frac{V_{out}(\omega)}{V_{in}(\omega)}$$ ...
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6 votes
3 answers
177 views

How can I filter out a signal while extracting only the desired one?

I know that my input signal contains a main sinusoidal signal, and I know its frequency but not its amplitude. Until now, I have been successfully using the least-squares method to generate a ...
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  • 161
5 votes
1 answer
137 views

How were the tones for DTMF chosen?

In my limited engineering knowledge, and limited research skills, I couldn't find a complete answer for the reasoning behind the chosen tones for DTMF. I did find a hint that said something about ...
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4 votes
2 answers
129 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 ...
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3 votes
1 answer
263 views

Arduino DAC to Speaker

I'm working with an Arduino Due's two DAC pins. I want to output to a single 4W 5.7Ohm speaker to test my code, with the intent of eventually outputting to a set of speakers (woofer, mid-range, and ...
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3 votes
0 answers
25 views

Pearson correlation of neural responses with it's linear estimation

I am trying to anderstand the following fact from this article (page 13): How can single neurons predict behavior Suppose I have a linear estimation of a stimulus: $ \hat{s} = \mathbf{w}^T(\mathbf{r} ...
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2 votes
3 answers
411 views

What is a Butterworth filter?

What is a Butterworth filter? I have raw X, Y, Z acceleration sensor data that I need to smooth them from noise. I have read that a Butterworth filter is one of the most appropriate for the specific ...
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2 votes
1 answer
67 views

What should be the sample frequency to test the response of a filter?

I am testing the frequency response as a filter as below, what should be the sample rate of the chirp signals, someone told me it should be at least 2 times of the input signals frequency, someone ...
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  • 55
2 votes
2 answers
316 views

Acoustical Design considerations for Active Noise Cancellation Project for Air vent [closed]

I am working on ''Active noise cancellation for air vent'' project. I am using NI myRIO1900 it has FPGA module(Xylinx Z-7010) , Audio Technica ATR 3350 omni directional microphones and Tevion ...
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  • 129
2 votes
1 answer
80 views

How do I study the frequency response of a physical system with Arduino?

I am a control engineering student and I am studying the frequency response of a system, so the Laplace domain, the Bode plot, poles, zeros,etc. ... I have clear grasp of their meaning, but if I think ...
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  • 23
2 votes
1 answer
101 views

Non-observable effect of low-pass filter on the Transfer function (of Vibration measured with Laser scanner)

I have to study the effect of low-pass filters (if any) on the outcome of the experiment. And the experiment here is to measure the vibration of a (metal) specimen by hitting the said specimen with ...
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  • 155
2 votes
1 answer
309 views

What happens when very bright coherent light and weaker incoherent background light passes through doubly cascaded diffraction gratings?

Double diffraction is where a light beam passes through an grating with distance D1 between ridges and then passes through an grating with distance D2 The image after passing through diffraction ...
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  • 179
2 votes
1 answer
157 views

Adaptive downsampling of time-series data?

I’ve been tasked with developing software to (among other things) log temperature data from samples in a furnace. Generally the temperatures are very steady, but can, at times, experience dramatic ...
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  • 155
2 votes
1 answer
39 views

Fourier serie signal approximation

I have to approximate the red function with Fourier harmonics. I am calculating complex Ck the following way. I am not sure what to put for period - T (6 or 2pi or what?). What integral limits to ...
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  • 21
2 votes
0 answers
42 views

How do you generate an impulse signal in a mechatronic system?

Background: I have a piezoelectric force transducer that I am using to measure the force produced by a combustion reaction in a tube. The issue is that there is a lot of ringing that occurs during the ...
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  • 21
2 votes
0 answers
10 views

In Digital Signal Processing, why is the spectrum of a signal with 'real' samples better than the spectrum of the same signal with padded samles?

Say we have number of samples to be 128 and a signal sin(2*pi*1000*n*Ts)+sin(2*pi*2000*n*Ts) sampled at 8kHz. Now say we have same signal but only N = 64 samples. But in order to create 128 samples, ...
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2 votes
0 answers
38 views

How to control an underactuated platform with a single servo

What's the best way to control the following type of platform so that it remains balanced and upright? It's a box supported by a single leg that can pivot at the foot (F) and at the hip (H). The foot ...
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  • 121
2 votes
0 answers
147 views

How does smartphone VR positioning work? [closed]

I've recently came across Google's cartboard VR headset, which allows you to use your smartphone as a virtual reality device. The headset basically splits the screen in your left and right eyes, ...
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1 vote
1 answer
44 views

Problem with RHP zero in transfer function

I have a transfer function with a RHP zero in $s=+1$, and I am trying to show in Matlab thath this limitation is present. In particular, initially I had a MIMO system, which I decoupled and then I ...
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  • 235
1 vote
2 answers
3k views

what is 1P frequency in rotor (wind turbine)?

In wind turbine, Is the number of revolution taken in 1s is called 1P frequency? If not, is it possible to find the 1P rpm from rpm measured for 1 hour (that is, I have 60 rpm data points from ...
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  • 111
1 vote
1 answer
73 views

Are there any methods to work out what appliances are running in my home from an aggregate power consumption sampled 6 times a minute?

I recently got a gizmo installed at home that samples my electricity usage once every 10 seconds. I've become a little transfixed watching the graph update as various appliances in my home turn on and ...
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1 vote
1 answer
56 views

How do mobile phones produce signals?

Normally it would require alternating currents to product electromagnetic waves. Yet as mobile phone is powered by batteries which only produces direct current, what type of mechanism/structure allows ...
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1 vote
1 answer
43 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)...
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1 vote
2 answers
61 views

What is the output of a signal in time domain that passed through a High Pass Filter with simple transfer function

If a signal function $ U(t) = 25 – (5 – t)^2$ is passed through a high pass filter with transfer function $\frac{s}{s + ω}$. what is the output signal Y(t). I know that the transfer function $H(s) = \...
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  • 33
1 vote
1 answer
27 views

How do I calculate the delay of two signals from different sensors?

Suppose: I have two sensors attached to a vehicle I have recorded the output of these two sensors (for example GPS) during a test ride each sensor has a different frequency one sensor is way more ...
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1 vote
2 answers
161 views

What are the conditions for a signal to be an energy signal and a power signal?

I know how to find the power and the energy of a signal. What I have a problem with is knowing whether a signal is an energy signal or a power signal. According to my teacher, a signal is a power ...
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1 vote
2 answers
80 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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1 vote
0 answers
29 views

Finding force distribution using accelerometer data

The team I'm currently working for is trying to compare bushings with different durometer ratings in the front suspension using single axis(z) accelerometer data during curb impacts. The current ...
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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 ...
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  • 161
1 vote
1 answer
57 views

classify ECG signal using neural network

I am looking to classify ECG signal using with neural network. I have never done signal analysis before. From the samples of data I have, I have noramlised, transformed using the FFT , get the pics, ...
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  • 113
1 vote
0 answers
523 views

How to use VBA on Aspen Hysys? [closed]

I am trying to write a program on Aspen Hysys. Hysys has a script manager to write scripts using Visual Basics for Applications syntax. Having no background in VBA, I'd like some help to: Import the ...
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  • 19
1 vote
0 answers
31 views

Why does Experimental Modal Analysis need a reference signal?

I need to conduct a vibration experiment with 3 accelerometers for a gear box. I'm reading the theory of mainly how to perform the vibration analysis but I don't understand why EMA needs a reference ...
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  • 399
0 votes
3 answers
149 views

PED or DSP for mechatronic student [closed]

I am doing mechatronics engineering and i am to choose an elective module. We have the choice of taking up Digital Signal Processing or Power Electronics and Drive. Majority of my friends are taking ...
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0 votes
1 answer
973 views

Difference between Hysteresis, low pass filter and deadband in control theory?

I am trying to understand the fundamental difference between the following terms in the context of control systems: Hysteresis Low pass filter Deadband Are these just fancy names that can be ...
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0 votes
2 answers
4k views

How to get natural frequencies from accelerometer measurements?

I will be performing some tests and measuring the vibrations of a planetary gearbox. The accelerometer I will be using stays attached to the gearbox and saves the data into a log, which is available ...
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  • 399
0 votes
1 answer
208 views

Is it possible to make a tunable coherent light filter with 1.8 nanometer bandwidth for visible light?

On January 1991, the esteemed Swedish professor of optics filed a patent titled "Coherence filter", that blocks coherent light regardless of laser light wavelength using destructive interference and ...
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  • 179
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 ...
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  • 1
0 votes
1 answer
47 views

how to filter model-free observations (e.g. Kalman filter)

Before asking a question, I have no background knowledge of engineering. So I have no idea about these issues like control or signal engineering. (Also, I'm not good at using English. sorry for that.) ...
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0 votes
1 answer
51 views

Operating a load cell below excitation voltage

I currently have this load cell, which has a 10V excitation voltage. However, there is a very nice/convenient load cell amplifier that works with an excitation voltage of 5 VDC. What are the ...
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  • 323
0 votes
1 answer
64 views

dB/s/Hz in spectrum efficiency

Here is link of research paper in which spectrum efficiency is given in terms of dB/s/Hz. How can we define it? https://jwcn-eurasipjournals.springeropen.com/articles/10.1186/s13638-016-0792-0
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0 votes
0 answers
16 views

Calculate Noise spectral density and rms noise from voltage signal data

I'm trying to come to grips with calculating noise figures starting from a generic electrical signal but I feel like even if the concept is theoretically in my head I'm not able to move forward. I ...
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  • 1
0 votes
0 answers
31 views

What is the best way to enhance an existing LTE signal on a mountain hut?

I'm traveling to a mountain hut in Austria every year which is in the middle of nowhere. If you're lucky you can sometimes get one bar and a weak Long-Term Evolution (LTE) or Edge connection for a few ...
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0 votes
1 answer
50 views

How to get difference equation from this block diagram

I was posed a very similiar block diagram in my exam from this book (Alan V Oppenheim Ronald W Schafer - Discrete-Time Signal Processing-Pearson Education) but couldn't solve it: I want to solve for ...
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  • 3
0 votes
1 answer
53 views

Calculating the transfer function of this block diagram

I'm not really sure what steps to take to solve the problem. I tried with G4 and G2 first but I'm not sure if that is the correct way.
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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 ...
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0 votes
1 answer
57 views

how to interpret plots in ISO 10816-8?

In ISO 10816-8 for reciprocating compressors, there are some plots that show the allowable RMS vs. frequency for every part of a compressor. However, in the text of the standard, it is mentioned that ...
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0 votes
0 answers
45 views

How to send true digital data in discrete values?

To my understanding signals in any form sent through empty space is in the form of electromagnetic waves. This implies that it is never discrete two values but it can be modulated. Looking at this ...
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  • 9
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; $H[z]=\frac{Y[z]}{X[z]}$ $H[z]=1+0.8z^\frac{-1}{5}$ ...
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