This is an optional decoding module not included in a normal CODE300-32 Standard or Extended version.

We have splitted the CODAN decoder into two separate decoder, but they can work interactive if requested. Both are running in multitasking. The CHIRP decoder measures the real center frequency of the transmitting station and tunes the data decoder automatically, and decode the ALE part of the transmission.

The CODAN DATA Decoder is a QPSK scheme it uses 16 in-band tones from 656.25 Hz to 2343.75 Hz, spaced 112.5 Hz apart. These centre frequencies are derived from a 600 Hz to 2400 Hz frequency spread and 112.5 Hz per Quaternary Phase Shift Keyed (QPSK) channel.

The CODAN DATA Decoder is fully automatic and supports compression and selective calling. The uncompressed throughput is 1475 bps, with compression 6000 bps is possible. CODAN is using several modes for transmission, the structure of each mode is different. These are:

• Non secure

• Non compressed

• Secure compressed non compressed

• Secure non compressed

• Broadcast mode

• Chat mode

Examples Codan decoding: on the left part of the decoding Chirp - LE,
right on top of decoding the HS data from a message in clear. 


Example of Codan decoding: left decoding of the long sequence Chirp - LE,
right on top of decoding the HS data of a message into groups of 5 letters.

Decoding of the HS part of a message (image) fax in Arabic.
For reasons of confidentiality this image is deliberately displayed in low resolution.