If you have an 8kHz PWM signal, running it through a 10kHz filter will have only a small effect on the waveform.
What is the purpose of this filter?
Normally you want to make the low-pass filter corner frequency low enough to recover the PWM modulation signal.
Sorry but I don't understand what you are talking about.
Are you saying the IPM modules operate at 8MHz (not 8 millihertz) and you want to operate at 8 kHz??
I couldn't understand what this filter will serve to ...
IPM works with time domain signals so either ONE or ZERO in PWM mode, what is your intention by using this filter ??
If your intention is to reduce the harmonics, they will be regenerated in the IPM module again..
PWM signals are already harmonically variable and rich signals, cutting-off at the input I think will not bring any advantage at all.