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Simulators >> Circuit Simulators >> Calculate noise parameters in 2-ports from spice
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Message started by Rolf on Aug 26^th, 2004, 6:14am

Title: Calculate noise parameters in 2-ports from spice
Post by Rolf on Aug 26^th, 2004, 6:14am

Hi,

other than in spectre, spice does not allow a S-parameter analysis including
noise. But to compute noise parameters I would only need the two equivalent noise current sources (or current and voltage at the input) of the two-port.

Could I obtain these using a standard SPICE noise analysis?

Title: Re: Calculate noise parameters in 2-ports from spi
Post by Frank Wiedmann on Aug 27^th, 2004, 1:48am

Noise parameters describe how the noise of a circuit or a device depends on the source impedance. So, you will probably have to perform several simulations with different values of the source impedance in order to find the noise parameters. You could for example try to implement one of the methods mentioned in http://www.rohde-schwarz.com/WWW/Publicat.nsf/article/n153_fsm/$file/n153_fsm.pdf in your simulation.

One difficulty in modeling the noise in SPICE might be the partial correlation that usually exists between the two equivalent noise sources. It might be possible to realize this correlation by using a noise source together with controlled sources like vcvs and vccs but I have never tried this.