System
Fusion is a digital communications mode for voice and data, including
pictures. It utilizes a customized, yet open, C4FM FDMA standard.
C4FM stands for Continuous
Four Level Frequency Modulation,
which is a special type of 4FSK, which is used in conjunction with FDMA
-
Frequency Division Multiple Access. FDMA is the same mode that is used
in P25
Phase 1 by public service groups, including Emergency Responders, but
it’s not
compatible.
What sets this new
technology apart from other digital voice
technologies, such as D-STAR, DMR, P25, and NXDN, is its backwards
compatibility with analog FM.
Automatic Mode Select
Every Fusion radio and repeater is aware of the current QSO
and it's mode, using a feature called Automatic Mode Select. This
function
instantly recognizes whether the received signal is C4FM digital or
conventional FM. The communication mode automatically switches to match
the
received mode. Even if a digital signal is being used, you can switch
to FM
communication if radio signals are received from an FM station. This
function
enables stress-free operation by removing the need to manually switch
the
communication method each time.
AMS function breaks down
into the following operating modes that are fully
selectable by the radio user:
AUTO: The both RX/ TX mode is
automatically selected from one of the four operating modes (DN, VW, DW
and FM) to match the characteristics of the received signal. This is
the current AMS operation.
TX MANUAL: The both RX/ TX mode is
automatically selected from four operating modes to match the
characteristics of the received signal. And if desired to change the TX
mode, by pressing the Microphone PTT switch momentarily, the TX mode
switch between DN and FM modes.
TX FM FIXED: The RX mode is
automatically selected from one of the four operating modes, but the TX
mode is fixed to FM.
TX DN FIXED: The RX mode is
automatically selected from one of the four operating modes, but the TX
mode is fixed to the ‘DN’ (Digital Voice Narrow) mode.
TX VW FIXED: The RX mode is
automatically selected from one of the four operating modes, but the TX
mode is fixed to the ‘VW’ (Digital Voice Wide) mode.
System
Fusion uses a similar DVSI AMBE DSP chip as used in DMR & P25, but
newer
than what's used in D-STAR.
System
Fusion Modes
V/D (Digital Narrow)– Voice+Digital or “V/D” mode
Voice FR (VW) Mode – Utilizes all available
bandwidth for high-fidelity voice
operation, providing the most crystal clear of voice communications.
Highspeed Data
Transfer data such as
images or text messages at full rate
with speeds up to 9600 Bits-per-second
Analog FM Mode
Maintains backwards
compatibility with existing Analog FM
Equipment, allowing a wide range of users to experiment with System
Fusion
Digital.
Capabilities such as
Automatic Mode Select (AMS) on the DR-1X
Repeater allow an even wider range of users to communicate, by running
the
repeater in “Fixed FM” mode on Transmit, and “Automatic Mode Select” on
receive
the repeater will automatically detect the incoming signal and convert
it to an
Analog FM Transmission. This mode allows digital users to communicate
with
existing Analog FM users without the need to switch their radios into
FM Mode,
allowing crystal clear Digital reception into the repeater that is
converted
into a conventional FM Signal.
System Fusion Repeaters in Maine, New
Hampshire, & Massachusetts
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