Passive filter ?
lately a friend got a small gadget that is placed between the TV antenna input and the antenna , this small gadget was able to filter certain scrambled channels to display a clear image .
im assuming this is a passive filter ,
have anyone used this before and is it a bandpass , rejection, high pass filter?
and if there is some schematics anywhere for this samll gadget
It is most likely a notch filter that removes a strong spectral tone added to the video signal.
Do not ask for illegal hardware or design details on this site.
I'm not sure about, but I think it's a bandpass filter with a variable central frequency, that means that you can change the central frequency of the passing band to make this one less larger and then eliminate noise frequency.
I think that's the principe of that gadget, sorry for my english I'm studying in french.
Regards
ok i just want to know what is this gadget i dont want any other imformation
and what is a good passive filter software design in the market
Gadget is sharp reject filter. You can try Filter Solutions program.
http://www.filter-solutions.com/
I think they hawe 30days trial.