Marine Radio User Manual

44 FT-857 Operating Manual
DSP CW PEAKING FILTER
(
DBF
) (
REQUIRES OPTIONAL DSP-2 UNIT
)
In the CW mode, pressing the
[
C
](
DBF
)
key in Multi Function Row “p”
[
DNR, DNF, DBF
]
activates a narrow-bandwidth peaking filter, which may be ideal for use under very crowded
conditions. The DSP CW Peaking Filter also is especially helpful under VHF/UHF weak-
signal situations.
The center frequency of the DSP CW Peaking Filter is automatically aligned to be centered
on the response you have selected via the Menu Mode in item No-027
[
CW PITCH
]
. See
page 101 for details.
1. To change the bandwidth of the DSP CW Peaking Filter:
2. Press and hold in the
[
C
](
DBF
)
key for one second on the CW mode. This instantly
activates Menu Mode No-045
[
DSP BPF WIDTH
]
, which allows selection of the band-
width of the DSP CW Peaking Filter.
3. Rotate the DIAL to select the desired bandwidth. The available values are 60 Hz, 120
Hz, and 240 Hz (default value: 240 Hz).
4. When you have made your selection, press and hold in the
[
FUNC
]
key for one second
to save the new setting and return to normal operation.
DSP NOISE REDUCTION
(
DNR
) (
REQUIRES OPTIONAL DSP-2 UNIT
)
The Noise Reduction feature of the DSP system may be used to enhance signal-to-noise
ratio on weak signals.
1. Press the
[
DSP
]
key momentarily. This instantly activates Multi Function Row “p”
[
DNR,
DNF, DBF
]
.
2. Press the
[
A
](
DNR
)
key to activate the DSP Noise Reduction feature. The “u” icon will
appear at the left side of the “DNR” indication, and the “ ” notation will appear at
the top on the display.
3. Now press and hold in the
[
A
](
DNR
)
key for one second. This instantly activates Menu
Mode No-049
[
DSP NR LEVEL
]
, which allows adjustment of the DSP Noise Reduction
level.
4. Rotate the DIAL to find the point where best signal-to-noise ratio is obtained under the
current noise conditions.
5. Press and hold in the
[
FUNC
]
key for one second to save the new setting and exit to
normal operation.
6. To turn off the DSP Noise Reduction feature, press the
[
A
](
DNR
)
key again.
If noise is present at a level which causes indication on the S-meter, the perfor-
mance of the Noise Reduction filter may be enhanced by rotating the SQL/RF
(RF Gain) control in a counter-clockwise direction so as to set the (fixed) S-meter read-
ing at the same level as the noise peaks. This adjustment raises the AGC threshold of the
receiver.
RECEIVER ACCESSORIES