Emission vs Frequency using FFT (EMC menu)

The voltage waveform computed by the analog simulator is translated by Fast Fourier Transform (FFT) into frequency domain energy. The X axis should cover the range 10-10,000MHz in logarithmic scale. The representation of the energy in Y axis is made in dBµV, equal to 20*log(V*1^e6). 1µV should correspond to 0dBµV, 1mV to 60dBµV and 1V to 120dBµV.

In the EMC menu, click "Emission vs Frequency". A specific screen with Log/Log units configured to display energy vs frequency is proposed, as shown below.

In the item "Use file", click the button and select the desired result file from WinSpice (.txt file). The corresponding spectrum appears. The FFT points are adapted to fit the information included in the simulation. The number of points may be adjusted manually. Several scaling buttons exist (Lin/log). Measurements may be also added to the figure. Several formats are supported. The most common is the simple tabulated dB vs freq (*.tab).

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