10 Jul
2023
10 Jul
'23
3:59 p.m.
On 7/10/23 11:19, Douglas Taylor via cctalk wrote:
I'm looking to see if it possible to do something
similar. Just blasting raw 12bit samples from memory out
the D/A board.
A fine point would be to use the KWV11-C realtime clock
board for the sample rate control. No interrupts, just
polling.
Harder is taking an existing MPG or WAV audio clip and
converting it into raw 12bit integers.
I wouldn't try this on the PDP11, I would do this in
Linux, offline, using python or octave to take a wide band
audio file convert it into a narrowband audio file, then
resample down to the rate I would use on the PDP11 and
finally convert the numbers into 12bit integers.
I think audacity will convert to any arbitrary sample rate.
I'm not sure if there's a way to set the bits/sample, but if
you turn the volume down you should be able to just truncate
the data.
Jon