I have some data sampled at regular intervals that looks sinusoidal and I would like to determine the frequency of the wave, to that end I obtained R and loaded the TSA package that contains a function named 'periodogram'.
In an attempt to understand how it works I created some data as follows:
x<-.0001*1:260
This could be interpreted to be 260 samples with an interval of .0001 seconds
Frequency=80
The frequency could be interpreted to be 80Hz so there should be about 125 points per wave period
y<-sin(2*pi*Frequency*x)
I then do:
foo=TSA::periodogram(y)
In the resulting periodogram I would expect to see a sharp spike at the frequency that corresponds to my data - I do see a sharp spike but the maximum 'spec' value has a frequency of 0.007407407, how does this relate to my frequency of 80Hz?
I note that there is variable foo$bandwidth with a value of 0.001069167 which I also have difficulty interpreting.
If there are better ways of determining the frequency of my data I would be interested - my experience with R is limited to one day.