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: Noise figure Q.
Unread postPosted: Thu May
13, 2004 6:55 pm
If a filter has 1dB IL at ambient, the noise
figure is 1dB. If at hot temperature, the filter has 1.5dB IL, will
the NF be higher than 1.5dB?
subject: Noise Figure will remain 1.5
Unread postPosted: Fri May
14, 2004 6:57 am
At higher temperature the overall noise power
floor will be higher (KTB). However, noise figure is the ratio between
the signal to noise ratio at the output to the signal to noise ratio
at the input therefore the noise floor is cancelled out and what is
left is the additive noise from the filter, or what you know as noise
figure. In this case the additive noise is 1.5dB, which is the noise
Post subject: Correction
to the formula
Unread postPosted: Fri May 14, 2004 10:48 am
Correction to the ratio you provided, the noise figure is the ratio
between the S/N in the input to the one in the output.
Unread postPosted: Tue May 18, 2004 11:38 am
NF is tested over temprature, is the ENR source in the chamber? Most
people have it out side the chamber and NF is calculated based on an
ambient reference temp.Posted