Modified Q analysis group with option to specify frequency range to filter out unwanted resonances

qfactor
filter

#1

The default high Q analysis group that is avalilable from the object library offers the possibility to specify the number of resonances based on the spectrum magnitude. The attached simulation file contains this analysis group with additional option to set minimum and maximum frequency in order to specify the range of frequencies where to look for the resonant peaks. Or in the other words, it removes any resonances that are outside of this range.

high_Q_resonator_with_spectrum_filter.fsp (339.0 KB)

In this example, the default spectrum looks like this:

If I want to remove the resonance at 245 THz, the modified Q analysis in the attached file allows me to set the frequency range of the spectrum between 260 and 400 THz:

and the resonance at 245 THz will be removed:

Plot of the filter to check what portion of the spectrum was filtered out:


#2

Nice tweak - thank you!

Do you know how to increase the spectral resolution of the resonance??
I have tried to increase the ‘zero pade’ in the script without any luck; the wavelength is still limited to xxxx.yy nm…

Thanks again,
Lars


#3

The analysis group uses fft, but it will not allow you to change the resolutions of the frequency vector returned. That said, it should be possible to use the czt command to perform the transformation instead. The second example on the czt page has a simple interpolation case to show the idea. If you would like more discussion on that, we can create a new topic on this.

If you meant the number of digits to output, you can try using the format long command in the analysis script.