Convolution of two delta functions in frequency domain

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SUMMARY

The convolution of two delta functions in the frequency domain, specifically [δ(ω-π) - δ(ω+π)] * (δ(ω+50π)-δ(ω-50π)), results in δ(ω+49π)-δ(ω-51π)-δ(ω+51π)+δ(ω-49π). This outcome is derived using the distributivity property of convolution. To compute this convolution, applying Laplace transforms simplifies the process by allowing the extraction of frequency information from both terms, followed by the use of the inverse Laplace Transform to obtain the final result.

PREREQUISITES
  • Understanding of Dirac delta functions
  • Familiarity with convolution operations
  • Knowledge of Laplace transforms
  • Basic principles of frequency domain analysis
NEXT STEPS
  • Study the properties of the Dirac delta function in signal processing
  • Learn how to perform convolution in the frequency domain
  • Explore the application of Laplace transforms in solving differential equations
  • Investigate the relationship between time and frequency domain representations
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Students preparing for exams in signal processing, engineers working with frequency analysis, and anyone interested in understanding convolution operations involving delta functions.

atrus_ovis
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Apparently, when convolving, for example:

[δ(ω-π) - δ(ω+π)] * (δ(ω+50π)-δ(ω-50π))

the result is
δ(ω+49π)-δ(ω-51π)-δ(ω+51π)+δ(ω-49π)

where δ() is the Dirac delta function, * the convolution operator and ω the frequency variable

How do we get to this? Can you help me on the intuition in this example and/or general in convolution in the frequency domain?

thank you.edit: i think i understand that we use the distributivity property to expand it.When we have , i.e. δ(ω+π) * δ(ω-50π) how do we continue?
 
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atrus_ovis said:
Apparently, when convolving, for example:

[δ(ω-π) - δ(ω+π)] * (δ(ω+50π)-δ(ω-50π))

the result is
δ(ω+49π)-δ(ω-51π)-δ(ω+51π)+δ(ω-49π)

where δ() is the Dirac delta function, * the convolution operator and ω the frequency variable

How do we get to this? Can you help me on the intuition in this example and/or general in convolution in the frequency domain?

thank you.


edit: i think i understand that we use the distributivity property to expand it.When we have , i.e. δ(ω+π) * δ(ω-50π) how do we continue?

In terms of actually computing the convolution, you can use Laplace transforms to get the "frequency information" of both terms, and then use the inverse Laplace Transform to get the actual result. With convolutions you just work out the Laplace transforms of T1, and T2 (in T1 * T2) and then use it in the way that was said above.

You could alternatively do it just with the actual definition though, but that would require a different approach. The Laplace way is a lot easier.

Do you know about Laplace transforms?

What have you tried so far? Maybe you should show some working or any ideas you had or tried that failed.
 
The course I'm on doesn't include Laplace transforms, so i guess it's not the expected way.

The equation I've written is part of a solved problem set, and I'm trying to actually understand why this result is correct because I'm preparing for my exams.
I know the rule about homework.I have the solution, I'm only asking for tips to understand it.

In the time domain, it's ok. f(x) convolved with δ(x-k) yields f(k) , as the delta function is 0 everywhere but k.
In the frequency domain, it seems that the frequency offset of the delta function, is simply added as an offset to the convolving pair.
 

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