real noise plots in SPICE?

Mar 31, 2005 26 Replies

I see that al of the time; make a change like that and the entries "push" down like they were in a stack. You have to go back and fix the last 3 entries by hand...

True; does not address the problem, which appears to be a bug.

Yes, i know; "vector sum". However, that does *not* addess the issues of:

1) SPICE reports noise values that are way different than theoretical. 2) Ohms law (ie reality) calculations for collector currents are *orders* of magnitude less than what SPICE reports.

Yes, i have seen the corruption created when one wants to change inoise or onoise specifications. It happens every time. Just manually correct the last 3 lines, click OK on the pop-up and the noise card should follow what you entered.

Seconded ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

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Hello Robert, then please come with an example schematic. I like schematics more than netlists. Why should you know better then the hundred- thousend who have used SPICE since decades and trust it.

Plese an example. It's clear that wrong inputs will lead to wrong outputs. SPICE is a math program. It can't discover any input error. Maybe a SPICE GUI should have some fuzzy logic to better guess what users have had intended in their netlist.

Best Regards, Helmut

]

Thanks for taking the time over this one.

I just spotted it.

I've been writing

..noise V(out) V(vset) dec 20 1 100K

Where V(vset) references an output port, called VSET connected to a voltage source, called V3.

That messes up the analysis and corrupts the data in the noise dialog tab. I should be writing.

..noise V(out) V3 dec 20 1 100K

whoops

DNA

DNA

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