Wraase Elektronik Model SC-1

The SC-1 is the latest model Wraase converter to be described here. It
is a portable
dual-mode unit for SSTV and FAX. Also available as optional extras are a colour
graphics keyboard, a video light pen, a computer printer interface and a colour camera
interface to allow the "snatching" of colour pictures from fast-scan. Later versions of
the SC-1 (serial numbers above 1000) are equipped with a new line
sequential colour sync system. A Ims long 2300 Hz pulse at the
beginning of each RED line is used to
synchronise the colour sequence, thus, even under strong received interference, the
colour will not change during reception of a colour frame.

These later versions have a "high resolution" colour mode in which both memory
banks are switched together for 256 lines colour. Transmission or reception of ones,
high-resolution colour frame takes 48-seconds.

Colour SSTV Standards: .

Frame-sequential colour: RED, GREEN, BLUE manually switched 1, 2 or 3%
frames each depending on propagation conditions.

Lime-sequential colour: RED, GREEN and BLUE lines alternating,
synchronised by the vertical sync pulse, starting with red. Sequence:
R-G-B.

Mafacturer's Specifications:

SC-1 SSTV/FAX Standards

SSTV/FAX FM-Modulation   Subcarrier Frequencies
  Sync:                    1200 Hz
  Black:                   1500 Hz
  White:                   2300 Hz
  Horizontal Sync:         5ms
  Vertical Sync:           50ms

                     SSTV 8s  SSTV 16s  SSTV 32s  Colour SSTV   FAX
Scanning lines        128      128       256         256        256
Picture elements/line 128      256       256         256        256
Line rate (lines/sec.) 16        8         8          16          4
Scan time/frame (secs)  8       16        32          24      64/128
Picture format        1:1      1:1       1:1         1:1         1:1

The U.K. agent for Wraase equipment is: Mr.A.Corker, 59 Foljambe Road, Eastwood,
Rotherham, South Yorkshire, S65 2UA. Telephone: 0709 68098.