phase alignment

Hello! I'm looking to the state variable filter proposed from ESP in Project 153 that is a state variable filter that splits the signal in 3 bands and sums them back together. this should give a flat response all over the spectrum when the bands are summed back together. I simulated the circuit...

Hi, I am new to RF-mixers, and i read that RF mixers should maintain the amplitude and phase relationship from the RF-input signal (Linearity). Do I use a wrong type of mixer, ore are there other ways of doing this. I can not get phase alignment. If anyone can enlighten me on this subject, I...