High resolution frequency detektor

[Henrik_V]

Hi,
great tool ..  
I was trying to detect small frequency variations with my android and here is my feature request:
A high resolution frequency detector
Autocorrelation and FFT based solutions are limited by the samplerate and sample size, one would be the reciproque counting method.

But there are even better methods: sine fitting
EVALUATION OF A STANDARDIZED SINE WAVE FIT ALGORITHM
Peter Händel
Abstract:
The IEEE Standard 1057 provides algorithms for fitting the parameters of a sine wave to noisy discrete time observations....



Or doing some more math on a FFT like:
https://forums.ni.com/ni/attachments/ni/.../tm3bb.ppt
found in
https://forums.ni.com/t5/LabVIEW/Extract...348#M83640

works great in LabVIEW, but I don't know what is protected in that part....

Both method prefer sine like signals but also work on everything that is periodic
(one could apply a bandpass before)  

My experiments are measure small frequency changes in a LC oscillator .. and detect small changes in µ_r or C ... 
(and try to power the circuit from the mic bias .. ; )  

Regards
Henrik

[Sebastian Staacks]

Thanks for the suggestion. I intended to implement some other methods for a while now, but never got around to it. I will bump it up a little bit on my todo list, but not yet sure when I will get to it. (This is something that could easily be contributed to our open source project as a new analysis module by someone who can write Java and/or Swift, just saying )