Wavecom W40PC, Manual

Page: 205 / 264

WAVECOM Decoders v6.15 W40PC, W41PC, W51PC Transmission Modes
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By selecting the “Auto” function, the software waits for the IOC identifier and synchronization
sequence. These signals are only transmitted once at the beginning of an image implying that
capturing of the signal will only take place at the start of the next image.
By selecting “WEATHER-FAX” the software starts immediately. The drum speed and the IOC
may be entered manually using the “
Drum speed ” and “ IOC ” items available from the
“Demodulator” menu. The selected values are displayed in the decoder status bar. In the short-
wave band, weather charts are transmitted almost exclusively with speeds of 60, 90 or 120
rpm. In the case of 60 rpm the drum rotates once per second, with 90 rpm at one and a half
times and for 120 rpm at a speed of twice a second. The index of co-operation (IOC) is readily
recognizable from the screen display when images are spread out too wide. An IOC of 576 is
mostly used on short-wave.
The decoder allows a continuous and smooth alignment of the image as it is being received via
the “
Fine Speed
” item in the “Options” menu. By using the “
Phase
” item in the “Options”
menu the entire image can be shifted into the correct position.
To enhance the interpretation of gray-scale images, a false color option is available. Right-
click on the image to open the z oom menu and from the bottom part select a color scheme. A
checkmark is placed to the left of the selection.
ZVEI-1
Parameter Value
Frequency range VHF/UHF
System SELCAL Analog
Modulation INDIRECT-FM
Receiver settings FM 12 kHz, narrow
Signal source AF (only)
Selective call systems are an efficient supplement to voice traffic.
The entire call number is transmitted by consecutive tones in decade sequence. When two
identical digits are to be transmitted consecutively, then an eleventh frequency is used as a
repetition identifier. If there more than two identical digits are to be transmitted the repetition
tone is appended to the digit tone (e.g. 22222 is transmitted as f2 fw f2 fw f2, where f2 is the
tone for “2” and fw is the repetition tone).
In most systems the accuracy of the single frequencies has to be 1/-1.5% of the
nominal value.
For ZVEI modes having a nominal tone duration of 70 ms, the duration of a single tone may
vary +/- 15 ms.
Decoding the selective calls is started by clicking on a system. If transmission and system
selection conform, the call sign is displayed on the monitor. In the “Options” menu a “Time
stamp” function can be enabled to add date and time to each call.
Tone Allocation
DIGIT ZVEI-1
0 2400
1 1060
2 1160
3 1270
4 1400
5 1530
6 1670
7 1830