Are there any RF guys here?
I'm developing a NOISE BLANKER for an HF-FM Radio.
The first IF of the radio is 45MHz, and I think to blank the RF on that stage. I finished the IF amplifier (90db with AGC) and the NB gate, but I need about 1us delay for the main IF path. I use Ansoft Designer and Serenade 8.0, there are a pritty good filter design tool, but I can't reach 1us of group delay with that. The best solution I've reached was with Bessel Aproximation and GD=400ns with BW=2MHz. It is good to have a wider bandwidth and flat GD response for easy tuning of the filter.
OK...,so my question is there any experienced person with RF filter design on that forum, to help me to find some solution on that problem.