DC offset removal and phase issues
The current filter I use is from the Xilinx app note on dc offset removal. However, it adds a noticeable phase shift to my signal of 9 degrees at the highest frequency, and around 40 degrees at the lowest. I am comparing this signal with a square wave and the phase is very important. I am sampling around 100 MHz and the signal is anywhere from 10 to 100 KHz. The square wave is the same frequency and is generated internally. The dc offset is not a constant.
A variable tap shift seems too expensive resource wise. Is there another good way to filter the signal?