Nr1 And Nr2 (Noise Reduction); Nf (Notch Filter) - Furuno FS-1575 Service Manual

3. NR1 and NR2 (Noise Reduction)

NR is processed by the DSP of the T-CPU board. The NR operates in SSB, LSB, and
AM modes. When two control units are connected to the system, common NR setting
can be made to each unit.
NR1 (low) filters voice-band components to suppress random noises without having
significant effect on voice signal components.
NR2 (high) has set filter parameters that further enhances suppression effect. As a result,
voice signals are affected to degrade intelligibility.
Noise: 800/1700 Hz
Example where NR1 is set to "ON"
in SSB mode

4. NF (Notch Filter)

NF is processed by the DSP of the T-CPU board. The NF operates in SSB, LSB, and
AM modes. When two control units are connected to the system, common NF setting
can be made to each unit.
The NF eliminates the noises of singular signals such as tone frequency. For example,
the NF detects a noise range to automatically eliminate the relevant band. Even if the
noise range moves, the NF will automatically move there to eliminate noises.
The NF is able to eliminate the noises of a number of signals if they get mixed in the
notch.
Noise: 1500 Hz
Example where NF is set to "OFF"
in SSB mode
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Example where NR2 is set to "ON"
in SSB mode
Example where NF is set to "ON"
in SSB mode
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7.6 T-CPU