Khz Fdma Technology - Icom IC-FR5100 Series Handbook

Range
Audio quality over distance is also greatly improved
with Icom's 6.25 kHz technology. Instead of the early
degradation of audio that you see in an analog signal,
the 6.25 kHz digital audio quality remains higher over
a comparable distance.
Because the emission mask is tight, 6.25 kHz channels can be used next to each other without causing
interference. The bandwidth measurements below show the 6.25kHz FDMA signal meets the FCC
designated emission mask requirements. (For reference only)
The figure on the left is the emission mask for a 6.25 kHz channel. The Icom 6.25kHz FDMA signal clearly
operates within the mask.
The IDAS system doubles the capacity of the current 12.5kHz channel allocation to meet any narrow
bandling requirements.
6.25kHz channel
6.25 kHz FDMA makes twice the number of channels available within the same spectrum as shown below.
This is a real solution to meet expanding demand for spectrum every year.
12.5kHz Analog FM
NOTE: The double capacity example shown above may not be applicable in some countries depending on
local regulations.

6.25 kHz FDMA Technology

Span 25.0kHz
12.5kHz channel
Span 50.0kHz
6.25kHz FDMA
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