8 FAX
114
be a multiple of 19200, in order that the SSTV synchronization processing works
correctly.
8.8.8
HSynch
Default setting: 50
Parameter: X 10... 100, position of the sync pulse.
Sets the effective point in time where a recognized SSTV synchronization pulse, as such,
is inserted into the received data-stream. Small corrections to the positioning of the
picture edges can be made here by shifting the entire picture right or left. Normally, no
changes in the
HSynch
default setting is required.
8.8.9
JSynch
Default setting: 1
Parameter: 0 LSB-SSTV-Sync
disabled.
1
LSB-SSTV-Sync
enabled.
Activates (1) or de-activates (0) the LSB-SSTV synchronization mode for SSTV. In this
mode, the PTC-IIIusb processes the SSTV synch-pulses separately, and re-introduces
them, according to the JVFAX convention, into the two lowest bits of each of the data-
bytes given out on the serial interface. If there is no synch-pulse present, then the two
lowest bits (0 and 1) are set to 1. The PTC-IIIusb erases the two lower bits for the period
of a synch-pulse.
8.8.10
SMode
Default setting: 1
Parameter: X 0... 15, SSTV sub mode.
Sets the SSTV sub-mode required. The
SMode
parameter is only used for the SSTV line-
synch processing, as it is only here that specific information about the various SSTV sub-
modes is required. If one wishes to work with any sort of SSTV signal, that is not in the
following list, then the
SMode
parameter must be set to 0.
This has the effect that multiple-line checking of the synch processing is turned off. The
PTC-IIIusb works perfectly satisfactory in this mode, but weak signals naturally lead
sometimes to a loss of synch with the normal synch pulse processing, with it's resultant
picture distortion.
The multiple synch-check (
SMode
parameter not equal to 0) will only work without
problem when the Modem baud rate (set via the
MBaud
parameter) a multiple of
19200, i.e. 19200, 38400, 57600, 76800 or 115200 Baud.