Re: gEDA-user: TwoStageAmp example

[al davis <ad136@xxxxxxxxxxxxxxxx>]

On Tuesday 03 April 2007 22:46, John Doty wrote:
> Yep. Of course what a low level digital video designer wants
> is   *noise* analysis at a particular point in time. And a
> simulator that could incorporate physical noise directly into
> a transient analysis would really get my attention.

Since you are doing digital, I guess your main concern is 
channel noise, not things like resistor noise.  Would a simple 
noise source fit your needs? 

How about a NOISE variant of a voltage source?  (along with PWL, 
SIN, and so on)  It seems to me that a random number generator 
with some filtering would do the job.  Those source functions 
are plugins in gnucap, so it should be easy  to make another 
one for noise.  They work for other components too, not just 
sources.

In almost spice syntax ..
V123 (1 0) noise bandwidth=20k amplitude=5

In verilog syntax ...
noise_source #(.bandwidth(20k), .amplitude(5)) V123 (1, 0);


How would you display the results?  I am thinking of the "eye 
diagram", which would require triggered retrace, like an 
oscilloscope.  I am not aware of any of our wave viewers that 
have this feature.


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