Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Manipulating data from tables
Posted 25.01.2013, 07:05 GMT-5 Results & Visualization Version 4.3a 1 Reply
Please login with a confirmed email address before reporting spam
Hi all,
I'm working on a model using piezodevice physics in the frequency domain, and I'm trying to plot admittance in dB (rather than siemen). I've found the admittance by taking the surface integral of the current density (pzd.JZ) over one of the electrodes, which results in a table with admittance values for each frequency. Is there any way to apply additional mathematical manipulation to the values in that table? To convert to dB, I need to take 10*log10(x) for each admittance value. I've tried doing the 10*log10(abs(pzd.JZ)) as the expression in the surface integral, but that doesn't work... though admittedly my math is a little fuzzy as to why not.
It seems like there must be an easy way to manipulate data in a table, but I can't seem to find it. Any advice would be greatly appreciated!
Thanks,
Jillian
I'm working on a model using piezodevice physics in the frequency domain, and I'm trying to plot admittance in dB (rather than siemen). I've found the admittance by taking the surface integral of the current density (pzd.JZ) over one of the electrodes, which results in a table with admittance values for each frequency. Is there any way to apply additional mathematical manipulation to the values in that table? To convert to dB, I need to take 10*log10(x) for each admittance value. I've tried doing the 10*log10(abs(pzd.JZ)) as the expression in the surface integral, but that doesn't work... though admittedly my math is a little fuzzy as to why not.
It seems like there must be an easy way to manipulate data in a table, but I can't seem to find it. Any advice would be greatly appreciated!
Thanks,
Jillian
1 Reply Last Post 25.01.2013, 19:08 GMT-5
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
I believe you should take the 10*log10( integration_of(...)) (or is it 20* ? amplitude or power) but you are applying the integration_of(10*log10(whatever)) this is not the same thing
Then dB is normally a ratio based on some value 1mW, 1m ... 1uPa
Only easy way around you define a variable as My_var = 10*log10( intop1(whatever)), and then plot the global variable My_var
or perhaps dB are in the units for your table (but which normalisation ? I expect not to find the dB there
--
Good luck
Ivar
I believe you should take the 10*log10( integration_of(...)) (or is it 20* ? amplitude or power) but you are applying the integration_of(10*log10(whatever)) this is not the same thing
Then dB is normally a ratio based on some value 1mW, 1m ... 1uPa
Only easy way around you define a variable as My_var = 10*log10( intop1(whatever)), and then plot the global variable My_var
or perhaps dB are in the units for your table (but which normalisation ? I expect not to find the dB there
--
Good luck
Ivar