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1-Visitor
April 14, 2015
Solved

FFT uncertainty

  • April 14, 2015
  • 2 replies
  • 1600 views

Hello,

In the attached program, a series of frequencies is measured using Fourier Transformation. The slope of the measured frequencies vs the actual frequencies shows a linear relation but the slope is not exactly "1".

Could you please help me to understand why the slope is not exactly "1" ? Is the any analytic relation between the uncertainty and sampling specifications?

Thank you very much in advance.

Payman

Best answer by RichardJ

The denominator in the calculation of delta_x should be N0-1, not N0 (if you have N0 data points, you have N0-1 gaps between them).

2 replies

RichardJ19-TanzaniteAnswer
19-Tanzanite
April 14, 2015

The denominator in the calculation of delta_x should be N0-1, not N0 (if you have N0 data points, you have N0-1 gaps between them).

payman1-VisitorAuthor
1-Visitor
April 14, 2015

Thank you very much.