Low pass filter cut off frequency

Hi Dhiman,

As far as I know, it is only the Shannon theory that relates bit rate and bandwidth by C=B*log(1+S/N) to estimate the channel capacity. Even though I have searched for it, I haven’t found any relationship between these two, except for some experimental relations like the ones in Optisystem samples in script mode.

I always watch the symbols in constellation visualizer before making the relation in the script to see if the symbols are drawn to the origin. If they are, then some frequencies the symbols are becoming zero (due to being filtered) and it shows that my allocated bandwidth is not enough and it is eliminating some symbols, so I have to increase it.

Dear dhiman,

kindly refer to some good books on RF microwave filters from your college library.

I also agree with what alitsu has said. I also do the same iterative process in order to get good constalletion. Vary the cut off frequency and see the best possible outputs available.

Also you need to check, what spectrum do u exactly need after filtering (I am the maximum or minimum frequency at the output filter) So accordingly you can decide the cut off frequency of the same