Quality Factor (Q Factor) is the ratio between the center frequency f0 and the half conductance bandwidth. It is used to measure the damping of a resonating device.
Conductance Plot
It is calculated using the following formula:
Extracting Q factor requires conductance of the device. To do this, the review file (*.revinp) must contain the following code:
pout
histname electrode vq all /* Volt/charge time histories 1 & 2
end
Once the input file is run, it creates a history file which is read into Review using the following code:
symb filename = INSERT_FILENAME_HERE /* Change filename as required
read f1 '$filename.flxhst' /* Read time history
The conductance of the device can then be calculated using the following code:
freq
file f2
wndo hann righ 1.
time pad $npad
type real
admt f1 2 f1 3
end
Then to get the value of f0, the #get command is used to extract the maximum peak value in the conductance curve. This value is then divided by 2 to get the values of f 2 & f 1 :
symb rpeak2 = $rpeak / 2
symb #get { incros } curvcros f2 1 $rpeak2 freq 2 $fmin $fmax
This gets the frequencies at the half conductance amplitude points which can then be used along with f0 to calculate Q:
symb Q = $rfreq / ( $freq2 - $freq1 )