I have a radar motion sensor, IPM-170.
The output of the sensor is as follows: The AC motion signal is -+300uv and there is a DC bias around 150mv.
I am applying the following circuit so I can run my sensor in the pulse mode.
When T2 goes to the saturation, the IF signal (DC bias + AC motion signal) goes to the amplifier. However, that high value of DC bias (150mv) enters my amplifier as a step input (a lot of frequencies) so it passes the DC blocking capacitor and it takes a long time to decay throughout the output of the two stages op-amps. Also, my AC signal would not be, of course, recognized during my limited ON period of the transistor.
How can I completely block that DC bias signal from the sensor?