Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Definition Posted: Mon Nov 05, 2007 6:42 pm
Jun 16, 2007 12:26 am
Can anyone please define in detail about these???
1) What is
the selectivity of a filter?
2) What is the mathematical expression for selectivity?
Post subject: Posted: Tue Nov 06, 2007 11:57 am
Joined: Tue Jun 26, 2007 10:27 am
Location: Dallas, TX
usually another name for how much attenuation is available in the stopband of a filter in a given frequency range.
It depends on what type of filter it is to what the mathematical representation will be. This is because different
filter approximations will have different transfer functions. However, the more poles in the transfer function
will make the resulting circuit act as the ideal 'brick wall'. A narrowband system will require a filter with very
high selectivity while a wideband system will require a low selectivity.
Post subject: Posted: Fri Nov 09, 2007 3:31 am
Joined: Sat Jun 16, 2007 12:26 am
Thank you very much for your help.