Finding Embedded Harmonics w/ Fourier Series & Integrals

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SUMMARY

The discussion centers on the limitations of representing the function f(x) = 1 over the entire real line using Fourier integrals. It is established that for a Fourier integral to exist, the condition ∫_{-∞}^∞ |f(x)| dx < ∞ must be satisfied, which is not the case for non-zero constant functions. Additionally, the conversation explores methods to find embedded harmonics in periodic functions through Fourier series and integrals, emphasizing the need for absolute integrability.

PREREQUISITES
  • Understanding of Fourier series and integrals
  • Knowledge of absolute integrability in mathematical functions
  • Familiarity with periodic functions
  • Basic calculus concepts, particularly integration
NEXT STEPS
  • Research the concept of absolute integrability in relation to Fourier analysis
  • Explore techniques for finding embedded harmonics in periodic functions using Fourier series
  • Study the properties and applications of Fourier integrals
  • Learn about the implications of non-integrable functions in signal processing
USEFUL FOR

Mathematicians, signal processing engineers, and students studying Fourier analysis who are interested in understanding the limitations of Fourier representations and methods for analyzing periodic functions.

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1) Why can't f(x) = 1, -&inf; < x < &inf; be represented as a Fourier integral?
Is it because it must be defined on a finite interval?

2) Could someone tell me how you find the embedded harmonics in a given periodic function using Fourier series and integrals? Either a quick demonstration or outline, or a link.

Many thanks.
 
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1) Perhaps it is because the integral &int;_infinity^infinity |f(x)|dx does not exist.
 
1) For the Fourier integral to exist, we require that [itex]\int_{-\infty}^\infty |f(x)| dx < \infty.[/itex] i.e. the function needs to be absolutely integrable, which no non-zero constant function satisfies.
 
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