lec22_handout - Fourier Transform • For non-periodic...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Fourier Transform • For non-periodic signals • Sufficient conditions – ∞ – Finite discontinuities • Convert time domain to frequency domain – to – Similar to Laplace transform ME365 Spectrum Analysis 1 Fourier Transform T A -d/2 d/2 • Even function 2 2 cos • Compare Ak to A0 2 sin sin ⋅ sin 2 2 ME365 Spectrum Analysis 2 Fourier Transform • Plot the spectrum – Spacing between points depends on T – As → ∞, spectrum plot becomes continuous ME365 Spectrum Analysis 3 Fourier Transform • Width of the first lobe depends on d – As → 0, bandwidth needed increases ME365 Spectrum Analysis 4 Fourier Transform • Converting time-domain to frequency-domain • Converting frequency-domain to time-domain • But is this integral an efficient use of your time? • Use Discrete Fourier Transform (DFT) ME365 Spectrum Analysis 5 Discrete Fourier Transform • Continuous time signal sampled at Δ Δ • DFT implemented with Fast Fourier Transform (FFT) – May require length of input vector to be a power of 2 – MATLAB does not require this, but it is faster – Consult the manual for your specific implementation ME365 Spectrum Analysis 6 ...
View Full Document

This note was uploaded on 12/26/2011 for the course ME 365 taught by Professor Merkle during the Fall '07 term at Purdue University-West Lafayette.

Ask a homework question - tutors are online