Analysis Methods
First published: 2004
Brief summary
CRI guide to Fourier analysis, data preparation, logs, differences, aliasing and interpreting spectra.
Article
There are many different techniques available in cycles analysis and this is a short guide to the main ones and when they are appropriate.
Fourier Analysis is the standard method for converting any time series into the sum of a series of sine waves of different frqeuencies. It is important to understand that any series can be exactly constructed from sine waves and so it does not prove that real cycles exist. However if a graph is made of the amplitude versus frequency of the components then real cycles will stand out as having much higher amplitudes, possibly on several adjacent frequencies.
There are methods to interpolate the frequency and find the best estimate for each cycle that is considered real.
It is desirable to have certain characteristics in data before it is analysed for cycles. One of these is that the fluctuations are of similarly meaningful amplitude of the time period.
Additional summary
The remainder demonstrates the method with wheat prices, spectral peaks, aliasing and harmonic interpretations.
Source details and credits
- Source / publisher: Cycles Research Institute
- Source type: Webpage
- URL type: WWW
- Credits: Cycles Research Institute
- URL: https://cyclesresearchinstitute.org/cycles/cycles-analysis/analysis-methods/