[SI-LIST] Re: Hspice Limitations

Hi All,
  Thanks for all of your comments. 
Actually I have missed on three things.
 1. The i/p to schmitt trigger doesnt come from o/p of
oscillator(as i had mentioned earlier), rather from
the i/p to the oscillator. seems with schmitt trigger
at i/p node, ckt is bound to be more noise immune.

2. The load capacitor on the oscillator is 15pf which
is huge compared to the capacitor load effect the
schmitt trigger can ever think of producing.

3. The ckt works well for higher freq range of more
than 15mhz. With lower range, o/p as well goes down
  So why wudnt there be no o/p on schmitt trigger? As
well the voltage swing at i/p and o/p nodes of
oscillator is reduced with schmitt trigger ckt
included.(but still within trip range).
 
  I would appreciate if anyone could comment!

Thanks in advance,
Partha!
--- "Ingraham, Andrew" <Andrew.Ingraham@xxxxxx> wrote:
> It sounds like something might be wrong with the
> Schmitt trigger circuit
> model.
> 
> It is apparently loading down the output of the
> inverter (which might be
> normal, I don't know), and it isn't responding to
> its input signal.
> 
> There can be many reasons for this.  I'd guess that
> something isn't
> "connected" right in your simulation.  Also try
> simulating just the
> Schmitt circuit alone to verify that it works.
> 
> Andy
> 
> 
> >   I am right now working on oscillator with
> Invertor
> > as its feedback to produce oscillations. The o/p
> of
> > oscillator is fed to a trigger ciruit to produce
> > pulse.
> >   For closed loop simulation without the schmitt
> > circuitry, the o/p of oscillator o/p moves almost
> > rail-rail. If i include schmitt trigger, the o/p
> swing
> > of oscillator reduces.
> >  Moreover there is no o/p from schmitt ckty even
> > though the schmitt trigger is set to trip within
> that
> > range.
> > 
> 
>
------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in
> the Subject field
> 
> or to administer your membership from a web page, go
> to:
> http://www.freelists.org/webpage/si-list
> 
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the
> Subject field
> 
> List archives are viewable at:     
>               http://www.freelists.org/archives/si-list
> or at our remote archives:
>               http://groups.yahoo.com/group/si-list/messages 
> Old (prior to June 6, 2001) list archives are
> viewable at:
>               http://www.qsl.net/wb6tpu
>   
> 


__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: