cici, this is an excellent design and it the way you have documented all the related issues is excellent. I need a small anti-jamming circuit for my GSM circuit and I was wondering how I can tune this particular circuit. From the looks of it, it stop the high frequency components and the low frequency components from a signal. It’s not very difficult to understand but what if I want to tune it in order to remove noise from the similar frequency that I’m tuned to listen the signal on.