[sdiy] Analogue Drift (was Re: HF VCOs and tracking problems)

[Ian Fritz]

At 05:26 AM 11/14/2012, rburnett at richieburnett.co.uk wrote:
>Thanks for your comments about my "VCO wobble" experiment, I had no idea 
>if anyone else was interested other than me and Tom!

It might amuse you if you missed it to go back in the archives and find the 
thread about Moogey Jitter.

>Another quick & easy way to see if an oscillator's frequency fluctuates is 
>to do a long-time FFT on its output using Octave or MATLAB.  Any frequency 
>variation is clearly visible as FM sidebands in the spectrum (sometimes 
>called "phase noise spurs")

In recent years the topic of Time Series Analysis has made a lot of 
progress.  JC Sprott's book is a decent intro.  There might be a way to go 
beyond Fourier analysis for this problem.

Ian