| ▲ | Lerc 8 hours ago | |
One of my to-do-one-day projects is an audio jack display system out of a Microcontroller. Was never quite sure if I should raw XY it or soft modem so I could decode on a web page on a handy device. | ||
| ▲ | retrac 8 hours ago | parent [-] | |
> raw XY it or soft modem How about analog raster scan? a.k.a. slow-scan TV? [0] Like how they returned the live television images from the Apollo missions. (They only had 1 MHz of bandwidth for everything - voice, computer up and downlink, telemetry, and TV. Standard analog broadcast TV was 6 MHz. So they reduced the scan rate to 10 frames per second instead of 60, and halved the horizontal line resolution -- that could fit in 500 kHz.) Most modern SSTV standards are super-narrowband, designed to fit into just a few hundred Hertz for amateur radio. But what if you had the full 20 kHz of bandwidth of a nice audio channel? With 100 horizontal lines per frame, and 1 frame per second -- that is about 200 cycles per horizontal line, or enough to resolve, in theory, 100 vertical lines on each horizontal line. I.e., 100 x 100 pixels (ish) at 1 fps. | ||