10 Dec
2008
10 Dec
'08
11:02 a.m.
How about using the pdp-11 to decode Morse code transmissions that you
receive on your vintage radio? This would eliminate any issues with
interfacing to HV circuits, as you could simply run the radio's audio
output through a PLL circuit to detect tone/no tone and then read this
single bit signal on the pdp-11. You decode the Morse code in
software. I have code for you (in an old version of Pascal) if you'd
like. It adapts to the Morse code speed automatically and "catches
up" to changes in Morse speed in about 5 letters maximum, as I
recall. From an undergrad project I completed in the late 1970s! I
could also dig out the hardware info. Then again you might have more
fun reinventing this yourself!
Kevin
On 9-Dec-08, at 4:00 PM, Ross Tucker 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"? 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!
So... any, er, "ideas"?
Best regards,
Ross Tucker
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