Such things are normally run at tens of MHz speeds, the higher the theoretically better resolution is possible but analog factors start getting in the way rapidly.
T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜
wrote:wrote:I use the world's simplest DAC (ONE resistor and ONE capacitor - that's all) to convert that digital one-bit signal to analog sound.
That's interesting. Sounds like how the PC speaker circuit is constructed. How exactly do you drive this? You have a high-resolution timer? What frequency does it run at?
First of all, there is a simple explanation of the technology - https://www.fpga4fun.com/PWM_DAC_3.html, I'm using a circuit #3. In my case the clock frequency is around 50MHz.
P.S. Do you know any software that runs on XT and uses DSP and OPL2 simultaneously ?
I would check mobygames. Games from around 1990 might support XT and Sound Blaster:
https://www.mobygames.com/browse/games/dos/tic,1/ti,17/1990/
Maybe SpaceQuest 1 VGA version supports all three. It will be horribly slow, but should work, I think.
Edit: EGA version of the remade SQ1 supports XT:
https://www.mobygames.com/game/space-quest-i- … ounter/techinfo
wrote:wrote:wrote:I use the world's simplest DAC (ONE resistor and ONE capacitor - that's all) to convert that digital one-bit signal to analog sound.
That's interesting. Sounds like how the PC speaker circuit is constructed. How exactly do you drive this? You have a high-resolution timer? What frequency does it run at?
First of all, there is a simple explanation of the technology - https://www.fpga4fun.com/PWM_DAC_3.html, I'm using a circuit #3. In my case the clock frequency is around 50MHz.
P.S. Do you know any software that runs on XT and uses DSP and OPL2 simultaneously ?
Yup, you need an extremely fast I/O pin and a fast DSP or FPGA to perform DDS of the PWM waveform. Conceptually the simplest method is to set the pin output as the result of a comparison between a periodic ramp or triangle wave function and the frequency space waveform of the audio signal.
All hail the Great Capacitor Brand Finder
Just for the collection - PoP full FM
