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Discussion of precise time and frequency measurement

Re: [time-nuts] low power divide by 5

Hal Murray

Thu, Jul 2, 2020 6:34 PM

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.

When did tubes die out?

How fast were transistors back then? How fast could you toggle a 12AX7?

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.

> 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. When did tubes die out? How fast were transistors back then? How fast could you toggle a 12AX7? 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.

Bob kb8tq

Thu, Jul 2, 2020 9:14 PM

On Jul 2, 2020, at 2:34 PM, Hal Murray hmurray@megapathdsl.net wrote:

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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Hi > On Jul 2, 2020, at 2:34 PM, Hal Murray <hmurray@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. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.