I am using this circuit to see the sine wave coming from a DsPIC Pins to check the shape of sine wave created from my sine table. PWM frequency is 18 kHz
But the sine wave does not seem to be not filtered properly. Also it seems to pick up some other noise or making its own oscillations when connecting the debugger to PC.
How should be the calculations or value for this filter or is there any other better options to see the sine-wave from my PWM output pins?