Computing the electromagnetic emission spectrum of pulses by convolution in frequency domain

To simulate the electromagnetic emission of an electronic system, also the behavior of the measurement instrument, an Electromagnetic Interference (EMI) receiver, needs to be emulated. This requires not only computation capability, but also the processing time is proportional to the length of the time domain input signal. As an alternative, this work investigates the usability of a convolution in frequency domain. Based on this approach a correction factor is derived to obtain the Peak detector reading for broadband disturbers directly from the result of an ordinary Fourier transformation. The pulse weighting characteristic of the other detectors is used to gain the corresponding QP and AVG reading. The solution is demonstrated on the example of a pulse train signal and the application of a data transmitter integrated circuit (IC).