[time-nuts] low power divide by 5

[Bob kb8tq]

Hi

> On Jul 2, 2020, at 2:34 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
>> Funny, just yesterday I was looking at the design of a laboratory cesium
>> beam standard from 1963. Sorry, there's no divide-by-5 example in there.  But
>> the attached images show the 108x multiplier (8.5 MHz to 9180 MHz).  Sure
>> enough, spot the 12AX7 and 6J6 tubes in use... 
> 
> Neat.  Thanks.
> 
> Interesting.  I'd expect transistors to be in use by 1963.

Some at low frequency, not a lot for high speed in production gear. A bit faster in 
terms of one of a kind lab devices. 

> 
> When did tubes die out?

They have yet to die out ….. :)

> 
> How fast were transistors back then?

The typical germanium transistor of the day was lucky to have an Ft rated in MHz 
(yes a slight exaggeration)

>  How fast could you toggle a 12AX7?

Depends on how fancy you wanted to get …. 10 MHz to 100 MHz.

Bob

> 
> Wikipedia says the first 7090 was installed Dec 1959.  The core memory cycled 
> at 2 microseconds.
> 
> Was 9180 MHz fast enough that it required a tube so it was simpler to use 
> tubes on the rest of the logic?
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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