41
votes
Accepted
What kind of hardware implements Fourier transform?
Devices using the Fourier Transform
It is very difficult for an electronic device to decompose a signal in different frequencies.
It's not.
There's actually quite a few devices that do that, ...
- 88.7k
25
votes
Accepted
Can I use the FFT to recognize musical notes on a piano?
The concept is good, but you will find it is not so simple in practice.
Pitch is not simply the predominant tone, so there's problem number 1.
The FFT frequency bins can't hit all (or even multiple)...
- 67.8k
22
votes
Accepted
Would a triangle wave have finite or infinite sinusoidal components?
a triangle wave is continuous
Quote from here: -
The triangle wave has no discontinuous jumps, but the slope changes
discontinuously twice per cycle
Having the slope change discontinuously also ...
- 436k
22
votes
Would a triangle wave have finite or infinite sinusoidal components?
instructor said that since the triangle wave is continuous it can be represented by a finite number of sine
You either didn't get this right or the instructor misspoke. It's not sufficient for the ...
- 311k
22
votes
Accepted
Do square wave exist?
As you know (since you mentioned the Fourier transform), a square wave can be represented (well, almost -- see below) as the sum of an infinite series of sine waves. But it would not be possible to ...
- 2,270
14
votes
Why is a signal that is finite in time domain, infinite in its frequency domain?
Many texts prove that a signal cannot be both time limited and bandlimited. It is quite a deep result and depends on complex analysis, but the shortest proof I know starts with a bandlimited signal \$...
- 3,083
14
votes
Accepted
Does the DC component of any signal also carry information?
A fixed DC signal has information - the DC offset - that would be lost if it were blocked (that is, reset to 0V potential.) The bandwidth of that information is nevertheless 0Hz.
This idea comes up in ...
- 50k
12
votes
Would a triangle wave have finite or infinite sinusoidal components?
Math proof:
Take a function made up of the weighted sum of a finite series of sine/cosine components.
Its derivative is also a weighted sum of a finite series of sine/cosine components. Same if you ...
- 70.8k
12
votes
What kind of hardware implements Fourier transform?
You can't get much more "bare metal" and "hardware" than a set of vibrating reeds.
https://www.stichtco.com/search?q=reed
So what hardware does a fourier transform? a bunch of ...
- 32.2k
11
votes
Why does my rectangle function on a FPGA look like this?
How long is the ground lead on your scope probe?
your scope probe should be in the X10 position and be properly compensated.
Remove the long ground lead that came with the scope probe and also remove ...
- 23.4k
11
votes
Under what conditions does jw equal the laplace variable s in an electrical circuit?
The Laplace variable \$s\$ relates to Fourier's \$j\omega\$ as follows:
$$
s = \sigma + j\omega
$$
Fourier transform can be seen as a Laplace transform when \$\sigma=0\$. The \$\sigma\$ allows the ...
- 2,642
9
votes
Accepted
How does one measure the Fourier components of a signal?
Is the signal split by many narrow band pass filters in paralell? Are these filters RLC circuits? Are there chips that contains many such filters in paralell?
No, these are typically collected as ...
- 88.7k
8
votes
Would a triangle wave have finite or infinite sinusoidal components?
Good answers abound here, but it really depends on your interpretation of "can be represented by".
One has to understand that a triangle wave is a theoretical mathematical construct that can not ...
- 46.4k
8
votes
Do square wave exist?
No, perfect mathematical square waves don't exist in real world because square wave is not a continuous function (it does not have a derivative at the step). Therefore you can only approximate a ...
- 130k
7
votes
Relation and difference between Fourier, Laplace and Z transforms
I will try to explain the difference between Laplace and Fourier transformation with an example based on electric circuits. So, assume we have a system that is described with a known differential ...
- 71
7
votes
Why does my rectangle function on a FPGA look like this?
This is normally called ringing and is common. If there is just single pulse then it is referred to as overshoot.
As you surmise it is caused by unintentional LC elements in the wiring being excited ...
- 32.2k
7
votes
Mathematically derived waveform vs. captured waveform from an analog synthesizer
the individual parameters on an analog synthesizer could be controlled digitally.
OK so far.
instead of using mechanical potentiometers to adjust some quality of the waveform (eg the frequency of a ...
- 311k
7
votes
Does the DC component of any signal also carry information?
There is pretty much nothing special about the DC bin, since it integrates frequencies around 0 Hz, the bandwidth is dependent on the FFT length, as for the other bins. So it is possible to encode ...
- 12.2k
6
votes
Accepted
On what condition does Harmonic components of power generated in 50/60 Hz Grid Generators depend on?
It could be the generator, but it's more likely to be the type of loads being driven.
A simple rectifier/capacitor DC supply draws current only around the peaks of the supply voltage waveform, ...
- 159k
6
votes
Do square wave exist?
In a more general case compared to the answers above, nothing can be stoped or started in zero time ie instantly. To do so would imply an infinitely high frequency component which would translate to ...
- 13.4k
6
votes
How does this modulation cause sidebands?
@Andy aka, yes, it is a CRM fixed-on-time(FOT) PFC
Because it's a fixed charge-time and a fairly constant slope transfer-time, the PWM modulation frequency MUST change because it has no other option. ...
- 436k
5
votes
Accepted
How do I replace a capacitor with a resistance?
Okay, you already know that an ideal capacitor is defined in the time domain by the equation
$$i(t) = C\frac{\mathrm{d}v(t)}{\mathrm{d}t}$$
Now you should also know (or at least vaguely remember ...
- 127k
5
votes
What is the meaning of my fourier transform results?
The first entry [1] in the FFT is your fundamental, but the zeroth entry [0] is DC!
A standard FFT will have the same number of output samples as input samples, and they will all be complex.
The ...
- 159k
5
votes
256-point FFT, but only need 5-6 frequencies, is there a better way?
If you wanted 1 or 2 frequencies, the Goertzel algorithm would be a clear winner.
If you wanted several dozen, then the FFT would be a clear winner, even after throwing away most of the resultant ...
- 159k
5
votes
Signal representation in frequency domain
Many people mistake necessary and sufficient reasons. Or if they don't mistake them, they don't spell out the difference, thinking it's obvious.
A time-limited signal will be unlimited in the ...
- 159k
5
votes
Why signal interval is -T/2?
One simple reason : \$[-\frac{T}{2} , \frac{T}{2}]\$ cover one entier period of the signal while \$[0 , \frac{T}{2}]\$ cover only half a period.
But, I think your true question is : Why \$[-\frac{T}{...
- 3,926
5
votes
Fourier Transform vs. Laplace Transform?
The differences can be found in the definition. A Fourier transform:
$$\mathcal{F}\{f(t)\} = F(j\omega) = \int_{-\infty}^{+\infty} e^{-j\omega t}f(t)dt$$
While an ordinary Laplace transform is given ...
- 5,082
5
votes
What kind of hardware implements Fourier transform?
Surface Acoustic Wave Devices were used as analog electro-mechanical devices to perform several signal processing tasks. Most papers are paywalled.
Chapter 16 of Colin Campbell's 1989 book Surface ...
- 3,399
5
votes
What kind of hardware implements Fourier transform?
This can be done on the - literally - bare metal level using the Harmonic Analyzer:
https://www.youtube.com/watch?v=NAsM30MAHLg
And sorry to give a link-only answer, but this one you really have to ...
- 2,999
Only top scored, non community-wiki answers of a minimum length are eligible