Alt-BEAM Archive
Message #00206
To: beam@corp.sgi.com
From: Jean auBois aubois@trail.com
Date: Fri, 05 Feb 1999 14:55:17 -0700
Subject: [alt-beam] Nv ring Synchronizer (was: BEAM clock)
At 12:41 PM 2/5/99 , dennison wrote:
>Synchronization? Seems to me I posted a not to long ago about something for
>just that.... :-)
Well, sort of... what you describe was more of a device that -indicates-
coincidence rather than causes synchronization. In other words, pulses
have to come along from both chains to the NAND gate at the same time to
change the output. That change in output could, indeed, create closely
sync'd pulses back into the chains or some other chain. What I'm talking
about (and perhaps this isn't even the right way to do things) is more like
one loop _causing_ a change in the other loop (moving to the next hour
indicator, for example).
Like Ben wrote, accuracy would almost certainly be extremely poor -- that
was, in fact, what I thought the biggest challenge would be. The hour loop
would most likely slip with regard to the minute loop and as a result the
pulses would almost never arrive at the NAND gate at the same time.
Besides which, what is required is that the minute part of the design
causes a -different- state change in the hour part every time it cycles.
Merely injecting a pulse from the minute loop into the hour loop doesn't
help 'cuz the hour loop would just become saturated (very slowly).
Actually, I'm afraid that Nv/Nu/Suspended technology can't do this without
referring back to the discretized world of registers and counters. For
example, the "on the hour" pulse from the minute loop could be used to
-clock- a single process around a loop of Nv latches (they have two
resistors connected to the bias point: one to Vcc and the other to ground.)
However, this is essentially a shift register and doesn't benefit to speak
of from BEAM/VSPANS.
By the way: I'm not building such a thing at the moment simply because I
still don't know how to do it.
Zoz
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