From: carl.lowenstein@gmail.com (Carl Lowenstein)
Subject: [pups] PDP-11 / vacuum tube interface
Date: Tue, 9 Dec 2008 17:37:31 -0800 [thread overview]
Message-ID: <5904d5730812091737g501a4b4ai98ac0862b13107be@mail.gmail.com> (raw)
In-Reply-To: <2f30dc950812091600t2028222dw3f855b2271a12593@mail.gmail.com>
On Tue, Dec 9, 2008 at 4:00 PM, Ross Tucker <rjtucke at gmail.com> wrote:
> Dear all,
> (This has got to be the strangest cross-post I've ever done.)
>
> I have just taken a bet from a friend to challenge my geekiness. I was
> telling him about my love of Vintage Technology and he proposed that I
> combine two hitherto separate hobbies and see what happens. The
> topics: the DEC PDP-11 minicomputer (vintage: 1970s) and vacuum-tube
> ham radios (vintage: 1960s). I do sincerely apologize for
> cross-posting, but I am rather younger than either of these
> technologies (vintage: 1984) and this seems like a monumental
> challenge.
>
> My question for y'all: how could I possibly design+build a project
> that uses both of these technologies? My thought is to port some radio
> receiver Digital Signal Processing (DSP) application into PDP-11
> assembler, compile and run it via emulator on my PC, then use it with
> the vacuum-tube regenerative receiver that I built a few years ago...
> Does anybody know if PDP-11 UNIXes even had the capability for a
> "sound card"?
Well, you could look at "Votrax" on Wikipedia. Allegedly, the first
words spoken by a Unix system at Bell Labs, using its Votrax
synthesizer, were "file not found".
Things that are now known as "sound cards" were called A:D and D:A
converters back in those days. And there were a fair variety of them
available for both Unibus and Qbus systems.
> Or, to get ambitious, I would LOVE to design some
> interface circuitry between PDP-11 digital circuitry and vacuum-tube
> electronics... The challenges are legion: the tube side of the circuit
> operates around 350V DC levels with radio-frequency (RF) signals at 7
> MHz (almost the clock rate of some PDP-11s!) and I don't have the DEC
> Handbooks, but I'm pretty sure that even those ancient pre-TTL
> circuits operate below 350V!
The vacuum-tube circuits may be running from 350 VDC but somewhere
there are low-level inputs from which everything is amplified. Think
microphone.
carl
--
carl lowenstein marine physical lab u.c. san diego
clowenstein at ucsd.edu
next prev parent reply other threads:[~2008-12-10 1:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-10 0:00 Ross Tucker
2008-12-10 1:37 ` Carl Lowenstein [this message]
2008-12-10 21:25 ` Bill Gunshannon
2008-12-11 0:04 ` Kevin McQuiggin
2008-12-11 0:06 ` Ian King
2008-12-13 0:49 ` Gregg C Levine
2008-12-13 1:14 ` [pups] PDP-11 / vacuum tube interface DAC-6A2 Gregg C Levine
[not found] ` <5904d5730812091737g501a4b4ai98ac0862b13107be@mail.gmail.co m>
2008-12-10 2:41 ` [pups] PDP-11 / vacuum tube interface Jay Jaeger
2008-12-10 2:49 ` Ross Tucker
2008-12-10 3:33 ` Ian King
2008-12-10 5:02 ` Kevin McQuiggin
2008-12-10 9:21 ` robinb
2008-12-10 9:22 ` Jochen Kunz
2008-12-10 18:09 Fred N. van Kempen
2008-12-11 17:14 ` Jochen Kunz
2008-12-11 18:16 Fred N. van Kempen
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