6.25 kHz FDMA Technology
9
Future Applications for 6.25kHz Technology
This new digital land mobile technology can be a platform for future integration of IT/IP/VOIP technologies. To
this end, there are some initiatives between a number of manufacturers to promote 6.25kHz technology more
widely. An example is the formation of the dPMR MoU in Europe, and the FCC in the U.S.A. has recently
proposed that system owners consider switching to 6.25kHz technology where possible. Japan and China are
also considering 6.25kHz for future digital radio standards.
Icom’s has implemented this technology in the
FR5100/6100 series. Backwards compatibility to
analog only radios enables a planned migration path
to “digital” with existing radios operating analog only
and new radios operating analog and digital.
General specifications:
Access Method : FDMA
Transmission Rate : 4800 bps
Modulation : 4-level FSK
Vocoder : AMBE+2™
Codec Rate : 3600 (Voice 2,450 + Error
Correction 1,150 bps)
Modulation with 4LFSK uses a symbol mapping
scheme. When the radio receives a binary number,
that number is mapped to a symbol, which is
interpreted as a 1050Hz frequency deviation.
The deviation is detected, filtered and “unmapped” as
a binary signal for transmission.
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