Digital Modes; D-Star; Dmr - DV Development Group DV4mini User Manual

Digital Modes:

The DV4mini can handle four digital modes:

D-Star:

D-Star was developed in Japan 1999/2000 especially for ham radio
and due to its clear and relative simple user interface the worldwide
leading system. Voice is being transformed by the AMBE
Vocoder into a compressed digital data stream of 3600 bits/s. In
addition there is a data channel with 1200 bits/s for a total data rate
of 4800 bits/s. This data signal modulates a carrier, so that a logical 0
is one frequency and a logical 1 a second frequency. This is called
2FSK (two frequency shift keying) or
GMSK (which is the same, however the signal is utilized with a Gauss
curve). This signal can be used to modulate most FM transceivers (via
the packet radio socket). This is the reason why there are any
home made D-Star solutions.
For communication three reflector systems are utilized.DCS (the
system with widest use), D-Plus REF
reflectors (mostly in the english speaking countries), and the x-
Reflector system which plays a minor role. DV4mini enables
communication via all these systems.

DMR:

DMR is a system designed for commercial applications. This is evident
in the user interface where numbers are used in lieu of call signs. DMR
modulates with 4FSK, indicating that it uses 4 frequencies (compared
to D-Star with 2 frequencies). This allows to double the data rate to
9600 bit/s. This higher rate allows the transmission of 2 channels at
the same time (2 time slots). The DV4mini always operates in time
slot 1 and in simplex mode. The radios must be confgured
accordingly.
Today there are two DMR networks in use. One based on Hydra
technology and the other on Motorola.
The DV4mini checks in to the Hytera network.However if Motorola
repeaters have installed the appropriate software they can also be
reached.
DMR reflectors have numbers in the range of 4000 to 5000, each
region has its reflector
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