eldo_user

Setting Up An Analysis
Transient Noise Analysis
• Transient response of the circuit, as generated by a pure transient analysis (the nominal
run).
• Transient response(s) with the added noise generated by the circuit (plotted as an
oscillogram of experimental measurements).
• The RMS value of the noise versus time, which gives the accuracy of the ideal transient
response.
To compute the RMS value of the generated noise, Eldo performs a normal transient
analysis of the circuit, plus N transient simulations which include noise sources within
the noisy devices. The RMS value of noise is computed at each time-step as follows:
Where V ο (t) represents the nominal transient response of the circuit, and V ι (t) is the i th
transient response of the circuit including the noise sources; N is the number of noise
runs performed (specified by the NBRUN parameter of the .NOISETRAN command). If
NBRUN=1, no RMS waveforms are created.
To perform transient noise analysis, Eldo adds a noise contribution to the same components as
in AC noise analysis (R, M, B, J, D). An additional noise model, connected with the Switch
macromodel (S), is available to simulate noise in switched capacitor circuits.
Figure 6-4. Circuit Components with their Added Noise Sources
Refer to the noise models in the respective sections of the Eldo Reference Manual.
See also:
• “Transient Noise Analysis Principles” on page 243
• “Specifying .NOISETRAN Parameters” on page 244
• “Transient Noise Analysis Results” on page 259
• “Transient Noise Analysis Example 1—High-Rate Particle Detector” on page 1368
242
Eldo® User's Manual, 15.3