RE: LF: TI-92 with sound...
[Prev][Next][Index][Thread]
RE: LF: TI-92 with sound...
On Mon, 18 Nov 1996, J. Kristian K. Nielsen wrote:
> >For example in normal ibm compatibles, that internal speaker is driven
> >with a purely digital signal. All digitized sounds played thru that kind
> >of speaker are done with some kind of pulse width modulation or something.
> >(Like in 1bit dacs in cd-players)
> >It would be easier to research possibilities of TI audio if someone made a
> >program which is capable of making different (adjustable) frequencies. If
> >there is no other possibilty than sending characters thru the port then
> >send character streams with correct 'shape', like 01010101b, 00010001b
> >and others like that..
> When you say "(adjustable) frequencies", what do you mean?. Sould the program send
> data with a speciel delay, like, when sending data to a DAC on a soundcard ?
> e.x. Sending a wav-file at frequencies 11kZ, to a DAC ?
Not exactly. I just mean that program should send just characters with
correct bit pattern like I showed there. Bitstream out of the port should
look like 010101010101010101010101 or something.. If there is no delays or
something between every 8 bits a some kind of noise 'signal' should come
out of serial port. If ports speed is locked to that 9600bps, different
frequencies (or noises with different tone :) could be done by sending
according bit patterns like 000100010001000100010001. Anyhow, if that's
possible, then it should be possible (if that serial port can drive a
earphone without external amplifier) to make noises with a simple setup
which consists of something like 2.5mm stereo plug, adjustable resistor
for signal attenuation and earphones. This is quite a poor design but if
it works, it would be easy to build and use. Sound quality stinks of
course but who cares anyway if the other option is no sound at all..
-Ipe
[ http://www.kotakk.fi/~y95silso ]
References: