Cw-morse, Dcs selcal – Wavecom W61PC V7.5.0 User Manual

Page 149

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WAVECOM Decoder W61PC/LAN Manual V7.5

Transmission Modes

139

CW-MORSE

The Auto function will automatically detect Morse keying speeds within the range 0 - 90 WPM (words per
minute). The keying speed is continuously updated and displayed.

Parameter

Value

Frequency range

HF

Operation modes

Simplex/Duplex ARQ, Broadcast

Modulation

CARRIER KEYING

Speed

0 - 90 WPM

Receiver settings

DATA, CW, LSB or USB

Input format(s)

AF, IF

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

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