-
Filter by Topic
Most Popular
All Topics
- List all discussions
LinkedIn
Facebook
Twitter
Delicious
Digg
Stumbleupon
More services...difference between eigenfrequency and frequency .
|
Thread index | Previous thread | Next thread | Start a new discussion |
RSS feed |
Turn on email notifications |
4 Replies
Last post: May 30, 2011 8:27am UTC
May 27, 2011 10:01am UTC
difference between eigenfrequency and frequency .
hi
can anyone explain what is the difference between eigenfrequency and frequency .
let us consider an eigenfrequency : 2.34567e5i or 4.87965e7 + 2.567e8i
so what will be frequency in both case .?
Reply | Reply with Quote | Send private message | Report Abuse
May 27, 2011 11:59am UTC in response to Vikram Kumar Singh
Re: difference between eigenfrequency and frequency .
Hi,
an eigenfrequency is a special case of an eigenvalue, which is a general mathematical term. You can have a look at http://en.wikipedia.org/wiki/Eigenvalues_and_eigenvectors
Cheers
Edgar
Reply | Reply with Quote | Send private message | Report Abuse
May 28, 2011 5:21am UTC in response to Edgar Kaiser
Re: difference between eigenfrequency and frequency .
thank u sir for ur reply
ya i understood in general what is eigenfrequency but
while simulating(comsol model) my model i am getting some eigenfrequency which is complex.
but i need resonant frequency in order to calculate Q factor
so how can i extract that frequency from eigenfrequency.
needed the help
waiting for ur reply sir
Reply | Reply with Quote | Send private message | Report Abuse
May 30, 2011 5:43am UTC in response to Vikram Kumar Singh
Re: difference between eigenfrequency and frequency .
Hi
another point I believe you are referring to is that complex frequency values means that you have damping, hence you should rather use Bodee plots with amplitude phase information (with abs() and atan2(imag(),real()) operators)
when you do a frequency domain plot, you will see that COMSOL proposes equations for the physics that are derived as harmonic time developments. While if you choose eigenfrequency, its the "classical" matrix eigenvalue that is used
--
Good luck
Ivar
Reply | Reply with Quote | Send private message | Report Abuse
May 30, 2011 8:27am UTC in response to Vikram Kumar Singh
Re: difference between eigenfrequency and frequency .
Hi,
to my knowledge in a complex eigenfrequency the real part stands for the system's resonance frequency in the undamped case and the imaginary part stands for the damping.
So, the imaginary part is already a measure for the quality.
If you kick such a system with a real part omega and imaginary part delta with delta << omega (damping is small) it will oscillate with the frequency sqrt(omega^2 - delta^2), which is lower than the undamped eigenfrequency.
Cheers
Edgar
Reply | Reply with Quote | Send private message | Report Abuse
Rules and guidelines
