Alt-BEAM Archive
Message #04540
To: beam@sgiblab.sgi.com
From: Wouter Brok w.j.m.brok@stud.tue.nl
Date: Wed, 16 Jun 1999 13:56:39 +0200
Subject: [alt-beam] Re: Bicore wasting energy; Power-smart head
Hello Evaristo,
>Sorry for the late response. Busy busy busy.
No problem, busy myself as well.
>I see. So you can determine if the duty cycle is either bigger or smaller
>then 50%. What if it's 50% ? The trigger levels of a HC240 are: Vh=2.0v min
>and Vl=0.8v min. Using inverters to determine 50% seems to be impossible
>due to their switching characteristics. Instead of U3, you could use a
>windows comparator using op-amps which will work. It will require some
>experimenting with the R3C3 to get a fast response time. Instead of op amps
>you could use transistors in conjunction with an inverter to create a level
>trigger with small hysterises.
Isn't that the HCT240 you have in mind?
I actually thought there should be inverters around (not TTL-compatible)
which have a smaller 'switching-interval' around Vcc/2 (if I read Wilfs
messeges correctly I though this was the HC240) ... If not then you are
right: then it isn't really possible
>Still if op-amps are used, why not just remove the bicore and hook the
>photo diodes directly to the window comparator. Fast response time and
>simple. This raises the following question: is it still BEAM? I would say
>yes.... why not? Sorry just had to ask.
You are absolutely right about this .... actually I'm busy just simulating
an mass-spring-damper-system with opamps .... just use them as integrators
and differentiators to get the differential equation oke.
About the not being it really Beam ... I don't really care; I don't think
one should restrict himself to just one technology if others are better. In
many things Beam is better than other technologies, but Beam is not
allmighty. Then again, thinking about it: with comparators you can imagine
them to be similar to the neurons used in Beam; in fact inverters can be
looked at as special comparators or opamps.
>OK it's seems to be very hard to create a schematic which can be used in
>conjunction with the bicore. Ofcourse it's possible but would require a lot
>of components (counters, bit comparators, latches etc). A simple solution
>doesn't seem to be possible. Since nobody else on the list seems to have a
>solution I think that this topic can be but in the freezer until someone
>comes across a solution. What do you think?
..... Mmmm, I'm still hoping for a fairly easy circuit, with a suspended
bicore. Maybe you are right that it isn't really possible, but I hope I can
prove you wrong sometime (I'll let you know if that happens) .... till then
the topic will be put in the freezer as far as the list is concerned ...
for me it will stay hot until I have a solution or until I am really
convinced of the fact that it isn't possible.
Thank you for discussing it,
Wouter Brok.
PS: if a brilliant idea might pop up in your mind anyway, then I'll be glad
to hear it.
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