WAVECOM Decoder W-PCI/e, W-CODE, W

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Parameter Value

Modulation

Symbol rate

FM, SUB FSK

1200 Bd

Center frequency

Shift/Bandwidth

Receiver settings

Input format(s)

Additional Info

1700 Hz

800 Hz

FM, BW = 12 kHz

AF, IF

ITA-5

DSC is used on HF and VHF. On VHF the symbol rate is 1200 baud and the center frequency is 1700 Hz and the shift is 800 Hz.

Selecting Options/Display offers the option of an ASCII or RAW bits display.

The complex structures of the DSC are described in detail in the ITU-Rec. M.493-11.

GOLAY/GSC

The GOLAY/GSC pager system originates in the USA and is based on the binary code found by Marcel

GOLAY/GSC. GOLAY has been in use since 1973. The first standard defined only tone calling and could handle a maximum of 400,000 addresses. After 1982 the system also allows for alphanumeric transmission and up to 4 million addresses may be selected via a coded preamble.

Parameter

Frequency range

Operation modes

Modulation

Symbol rate

Receiver settings

Input format(s)

GOLAY Addressing Format

Value

VHF

Broadcast FEC

FSK

300/600 Bd adaptive

FM, BW = 15 kHz

This illustration shows the basic address format of the Golay Sequential Code (GSC). It is constructed from two code words which are derived using the Golay (23,12) algorithm. The bit rate for each code word is 300 bit/s. Each received Golay word can contain up to three errors before integrity is compromised. The

GSC is asynchronously decoded. To separate adjacent addresses, a separator word (comma) is transmitted at a rate of 600 bit/s.

The message format is based on eight BCH (15,7) code words that are grouped together to have exactly the same length as an address. Messages and addresses are thus easily interleaved. Each message block may contain up to 12 numeric or 8 alphanumeric characters. Messages which are longer than a single block may be transmitted using any desired sequence of blocks. By implementing block coding, two errors may be corrected in the BCH (15,7) codeword. The bits within a block are interleaved during transmission which allows the correction of burst errors affecting up to 16 bits, which is equivalent to a fading protection of 27 ms.

GOLAY Data Block with Eight Alphanumeric Characters