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Figure 6-10. PSD of a Flicker Noise Signal
Setting Up An Analysis
Transient Noise Analysis
In the Power Spectral Density shown in Figure 6-10, FMIN_FLICKER is set to 1MHz and
FMAX to 100MHz. The signal has a white spectrum for frequencies below 1MHz, then a 1/f
shape (inversely proportional to the frequency) between 1MHz and 100MHz and then a sinc
shape.
Noise Sources Generated From a Sum of Sinusoids
When FMIN≠0, the r(t) part of the source is generated from a sum of sinusoids with random
phases. All the sinusoids have the same amplitude, and the frequencies are determined to
provide the source with the correct color (frequency dependency). The frequency distribution
can be seen on PSD plots.
For instance, white noise sources are obtained with evenly distributed frequencies between
FMIN and FMAX, as shown in Figure 6-13. Flicker noise sources are generated from a
logarithmic frequency distribution as shown in Figure 6-16.
The m(t) part of the noise source is computed from the PSD of the noise model. As PSD is bias
dependent, m(t) is instantaneously updated function of bias changes.
Eldo® User's Manual, 15.3 253