Hello,

Having fixed the spelling error from the "NIntegrate and Unit Step" thread, I'm now getting an answer of zero when applying NIntegrate[] to one period of a 50% duty cycle unit pulse of 61.0352 nsec duration. I should be getting an answer of 0.5. A notebook showing the calculation is attached. I used both UnitStep[] and HeavisideTheta[] to form the pulse. The answer was the same. So it looks like some sort of precision issue to me but I'm not sure. Anyone have any ideas on how I can get NIntegrate[] to give me the correct 0.5 for this case? What motivated this is that I'm getting the same zero result for DC term result when applying FourierSeries[] to this pulse.

Thanks.