.NOISE Record

The NOISE record requests a frequency dependent noise analysis of the circuit. The noise analysis is performed along with an .AC or .VARY analysis. The noise analysis uses the noise parameters from the OA, BJT, and FET models and generates noise sources for each real resistor and conductance in the circuit. The magnitude of the noise spectral density calculated at the first requested output is provided as the first part of the noise result. The units (either dB[magnitude / $\sqrt{Freq}$] or magnitude / $\sqrt{Freq}$) are specified by the units selection parameters on the .OPT record. The second part of the noise result is the integrated noise as described below. The units for integrated noise are either Vrms or Arms. Note that a zero noise result can only occur as a result of an error. For example, if the noise from an op-amp is requested but the op-amp model does not have specified noise parameters, a zero noise results.

The '.' before NOISE must be in the first column of the record.