SSTV in MFSK16
Created by : Nick Fedoseev (UT2UZ) and Denis Nechitailov (UU9JDR) in 2003
It is a SSTV mode without
transmission of a synchronization ray, in color or in black and white
mode, where the picture may be transmitted among MFSK16 text.
The picture format is not fixed as in classical SSTV but variable
(limited to small pictures). Multipsk proposes to use the
standard "320x256" to take advantage of the SSTV "workshop" and the
stored SSTV pictures.
The band of frequencies used is 234,375 Hz (15 x 15,625 Hz), which is
the width between extreme peaks of a MFSK16 transmission. The duration
of a pixel is exactly 1 ms. In color mode, the colors are transmitted
in the following order: Red, Green, Blue. In black and white mode, the
black color corresponds to the lower frequency and the white color to
the higher frequency.
To be recognized, the picture must be MFSK16 prefixed by:
* "Pic:320x256C;" for example for a color picture of 320x256 dimension whose transmission will last 320x256x3x0,001=246 sec,
* "Pic:320x256C;" for example for a black and white picture of 320x256
dimension whose transmission will last 320x256x1x0,001=82 sec.
on this program, for a better appearance, the grey level is computed
according to a "physiological" formula: Grey level = 0,30 x Red level
+ 0,59 x Green level + 0,11 x Blue level
Recommanded frequencies for SSTV in MFSK16
Note : for SSTV in MFSK16, in general, it is not
authorized to transmit a mix of text and pictures because the authorized
frequencies, for these modes (MFSK16 / SSTV), are different.