An Approximate Fast Fourier Transform Technique for Vernier Spectral Analysis
Abstract
An approximate and quick fast Fourier transform technique for vernier spectral analysis is derived and tested for several candidate time-and delay- weightings, and for overlaps of the time weightings. For 50 percent overlap, the use of a simple cosine lobe for the time weighting yields spurious spectral sidelobes at least 23 dB below the main peak, whereas Dolph-Chebyshev time weighting achieves -33 dB sidelobes. For 75 percent overlap, use of a (cosine) (sup 5) lobe for the time weighting yields sibelobes at least 54 dB down, whereas Dolph-Chebyshev time weighting achieves -86 dB sidelobes. In both cases of overlap, use of delay weighting is also required and is taken as a Hanning weighting. Extensions to other overlaps and weightings are possible from the fundamental relations presented and from the sample program furnished.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 16, 1974
- Accession Number
- AD0785850
Entities
People
- Albert H. Nuttall
Organizations
- Naval Underwater Systems Center