Week of 11/5
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Revision as of 15:43, 9 November 2007
Here is the display of my oscilloscope when the input is a 1000 pulse per second output of a time-code generator. (The time-code generator is a device that locks to the 10 MHz output of an atomic clock and produces 1 Hz or 1 KHz pulse trains as well as human readable time synchronized to the atomic standard.)
I imported the data and plotted it along with its periodogram.
Notice that only the odd harmonics are present.
Here is a mathematica notebook that simulates this.
 Download lots of fourier transform examples
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Sampling theorem. See 10/31/07 lecture notes
We end up with
This amounts to taking samples of the data every 1 / 2fs and multiplying them by a sinc function and adding up the results.
| Download Sinc function interpolation via the samping theorem
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Mathematica can find the fourier transform of a box function of width h centered on zero times sin(2πx):
| Download FT of finite sines
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 Download 11-7-07 notes
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| Download timing the fft
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| Download Nyquist exercise
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| Download cool sound examples with Mathematica
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| Download 11-9-07 notes: Fourier series example from a boundary value problem
|
