Re: [Discuss-gnuradio] Transition width

[Ron Economos]

It's the width of the filter response from the -6 dB point to the -60 dB point. On analog radios, it's called the "shape factor" of the filter and expressed as a ratio (a 500 Hz filter at -6 dB with a 2.0 shape factor will be 1000 Hz wide at -60 dB).

Here's a small flow graph that illustrates the transition width.

http://www.w6rz.net/filter.grc

Here's the filter response with a transition width of 200 Hz.

Here's the response with a transition width of 2000 Hz.

The smaller the transition width, the greater the number of taps required to implement the filter. More taps requires more CPU cycles, so be careful when setting the transition width. Too small a width can create a filter that takes more than 100% of your CPU.

Ron

On 11/02/2017 12:54 AM, Thom L wrote:

Hello,

I can't understand what the "transition width" parameter represents when filtering in gnuradio .. And how to adjust it effectively?

Thanks 

Thomas