Wavecom W74PC V8.7.0 - Manual (Page 163)

WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V8.7.0 Transmission Modes

153
The center frequency can be set to any value between 200 and 3400 Hz via the Center item in the De-
modulator menu. The center frequency is nominally 800 Hz which is dictated by the quartz filters of pro-
fessional receivers while other receivers work with 1000 Hz.
The shift can be set between 100-300 Hz and controls the lock-in-range of the center frequency (band-
width = 1.2 x shift).
Using Options | Alphabet the output can be set to Latin, Cyrillic, Greek, Arabic or Hebrew.
Using Options | AFC the continuous automatic tuning to the center frequency of the CW-Morse signal can
be enabled or disabled.
The software reports an error condition (ERROR) if the controlled parameters as the dot-dash ratio, the in-
ter-word or inter-character breaks deviate too much from the standard, and error-free decoding cannot be
maintained.
DCS SELCAL
DCS stands for Digital Coded Squelch (also known as DCSS, Digitally Coded Squelch Signaling), and is
used for selective calls and remote control applications.
Parameter Value
Frequency range VHF
Operation modes Digital Selcal
Modulation FSK
Symbol rate 133.7,134.4, 137 Bd
Receiver settings FM, BW = 15kHz
Input format(s) IF
The data is transmitted on sub audible tones within the frequency range 2 Hz to 300 Hz. In practice, DCS
is similar to CTCSS, but uses 104 octal 3-digit code words instead of continuous analogue tones.
The data is sent as a series of 23-bit GOLAY encoded frames without any sync bits. Polarity can be normal
or inverse, and must be selected by the user.
DCS Code Table
Normal Inverse Normal Inverse Normal Inverse Normal Inverse
023 047 155 731 325 526 516 432
025 244 156 265 331 465 523 246
026 464 162 503 332 455 526 325
031 627 165 251 343 532 532 343
032 051 172 036 346 612 546 132
036 172 174 074 351 243 565 703
043 445 205 263 356 212 606 631
047 023 212 356 364 131 612 346
051 032 223 134 365 125 624 632
053 452 225 122 371 734 627 031
054 413 226 411 411 226 631 606
065 271 243 351 412 143 632 624
071 306 244 025 413 054 654 743
072 245 245 072 423 315 662 466