														D-Star Reference 20090128
														=========================

														by Jonathan Naylor  G4KLX
														with contributions from
																Howard Long  G6LVB
																Satoshi Yasuda  7M3TJZ


This software is the first rather primitive version of a D-Star transmitter and
receiver. Currently it is buildable under Windows under Visual C++ 2008 (the free
one), but apart from the WAV file handling, should be relatively portable.


D-Star Receiver.exe
===================

This program takes as its input a WAV file recording of a D-Star transmission that
has been recorded directly from the output of a discriminator. It is run as:

"D-Star Receiver" <WAV File Name>

Where <WAV File Name> is the name of previously recorded D-Star data.

Provided that the audio is clean enough, and the signal strong enough, the D-Star
data within the transmission will be written to three files. The names of these
files is based on the date and time when the program was run. Examples of these
files are:

AMBE_20090127_193116.dat
DATA_20090127_193116.dat
INFO_20090127_193116.dat

When run an amount of debugging information, including the output file names, will
appear on your screen.

The AMBE and DATA files contain the raw data from the audio data and the slow data
respectively. Potentially the AMBE data could be send to an AMBE decoder, and
received audio will appear, however this has not been tested yet. The slow data
typically consists the radio header which contains the callsigns, flags and a
checksum. This is repeated as many times as possible during the transmission. It
is also possible to see GPS data being sent also. The program makes no attempt to
do more than write this data out to the file.

The INFO file is in reality a text file, and contains a full textual explanation
of the data in the radio header. The data in the AMBE and INFO files can be used
as input to the counterpart transmitting program.


D-Star Transmitter.exe
======================

This program takes AMBE and data from an INFO file and builds up a suitably
formatted WAV file, which should be able to be used to modulate an FM transmitter
and hence create GMSK and be receivable. It is run as:

"D-Star Transmitter" <INFO Data File> <AMBE Data File>

The format of the input files is exactly the same as that output by the D-Star
Receiver program. The DATA file isn't used as the transmitted slow data is
created from information within the INFO file, and is in exactly the same
format as a default D-Star radio which isn't being used to transmit GPS
information.

The output is a mono WAV file using a sample rate of 48000Hz. The filename used
is based on the date and time that the program was started, for example:

DStar_20090128_123209.wav

Being a WAV file means that it can be played on speakers, although I wouldn't
recommend it. In the same way that the output of the receiver program can be
used as an input to the transmitter, so can the output of the transmitter be
fed into the receiver.


Format of the Files
===================

The INFO file is editable to suit your requirements. Here is an example:

Type: Voice packet
Mode: Via repeater
Interrupted: No
Control signal: No
Urgent priority: No
Repeater flags: None
Destination repeater callsign: GB7OK   
Departure repeater callsign: GB7OK   
Companion callsign: CQCQCQ  
Own callsign 1: G4KLX   
Own callsign 2:     

The other files are essentially binary files, the DATA file will usually contain
many printable characters, but may also contain binary flags, a checksum, and 
length and type information.


Future Plans
============

The aim is to eventually work these up into a software transceiver that would be
able to make use of a 9600Bd connection into a V/UHF radio, and with the addition
of a DV-Dongle, full D-Star operation will be possible. The full version will be
a GUI based application that will run on Windows, Linux and Mac OS X.
