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What is System Fusion?


System Fusion

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 its 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.

Here's a look at bandwidths used by different analog and digital modes, including FDMA:

Bandwidth Comparison



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's Four Digital 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.

FDMA Multi Mode

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.



Nearby System Fusion Repeaters


Call Sign

W1NPP
KS1R
W1NPP
K0LDO
WS1EC
W1MWV
W1JY
W1ALE
KV1VTL
W1CNH
W1MWV

Location

Auburn, Goff Hill
Phippsburg
Poland Spring, White Oak Hill
Brunswick, Woodward Cove
Windham
North Conway, Mt. Cranmore
Sanbornton
Pembroke
Kensington, Waymouth Hill
Gilford, Gunstock Mountain
North Conway

State

ME
ME
ME
ME
ME
NH
NH
NH
NH
NH
NH

Frequency

146.610 -
147.210 +
147.315 +
147.330 +
449.225 -
145.450 -
146.670 -
146.940 -
443.450 +
447.775 -
448.775 -

Tone

88.5
100.0
103.5
100.0
103.5
100.0
123.0
114.8
88.5
NONE
100.0

Use

OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN




Additional Resources



Yaesu System Fusion
Which Digital Mode is Right for You?  - K3DO

A Comparison of Digital Voice Modes
System Fusion Overview - N5WDG






  

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Wireless Society of Southern Maine, P.O. Box 6833, Scarborough, ME 04074