Transient noise source -

General Form:

TRNOISE(NA NT NALPHA NAMP RTSAM RTSCAPT RTSEMT)

Examples:

VNoiw 1 0 DC 0 TRNOISE(20n 0.5n 0 0)      $ white 
VNoi1of 1 0 DC 0 TRNOISE(0 10p 1.1 12p)   $ 1/f
VNoiw1of 1 0 DC 0 TRNOISE(20 10p 1.1 12p) $ white and 1/f
IALL 10 0 DC 0 trnoise(1m 1u 1.0 0.1m 15m 22u 50u)
                                          $ white, 1/f, RTS

Transient noise is an experimental feature allowing (low frequency) transient noise injection and analysis. See Chapt. 15.3.10 for a detailed description. NA is the Gaussian noise rms voltage amplitude, NT is the time between sample values (breakpoints will be enforced on multiples of this value). NALPHA (exponent to the frequency dependency), NAMP (rms voltage or current amplitude) are the parameters for 1/f noise, RTSAM the random telegraph signal amplitude, RTSCAPT the mean of the exponential distribution of the trap capture time, and RTSEMT its emission time mean. White Gaussian, 1/f, and RTS noise may be combined into a single statement.

Name	Parameter	Default value	Units
NA	Rms noise amplitude (Gaussian)	-	V, A
NT	Time step	-	sec
NALPHA	1/f exponent	0 < α < 2	-
NAMP	Amplitude (1/f)	-	V, A
RTSAM	Amplitude	-	V, A
RTSCAPT	Trap capture time	-	sec
RTSEMT	Trap emission time	-	sec

If you set NT and RTSAM to 0, the noise option TRNOISE ... is ignored. Thus you may switch off the noise contribution of an individual voltage source VNOI by the command

alter @vnoi[trnoise] = [ 0 0 0 0 ] $ no noise

alter @vrts[trnoise] = [ 0 0 0 0 0 0 0] $ no noise

See Chapt. 17.5.3 for the alter command.

You may switch off all TRNOISE noise sources by setting

set notrnoise

to your .spiceinit file (for all your simulations) or into your control section in front of the next run or tran command (for this specific and all following simulations). The command

unset notrnoise

will reinstate all noise sources.

The noise generators are implemented into the independent voltage (vsrc) and current (isrc) sources.