Page 55FT-
991
(
)
The IF NOTCH lter is a highly eective system that allows cutting out an interfering beat note or other carrier signal
from inside the receiver passband.
1. Press the
F
button to show the functions
listed on the TFT display.
2. Touch
[
]
on the TFT display. The Notch
function will be set to “
ON
”.
MULTI Knob
F
(
M-LIST
)
Button
NOTCH indicator
NOTCH level indicator
3. Rotate the
knob to adjust the “null” position
of the Notch lter.
4. To cancel the NOTCH lter, touch
[
]
on the
TFT display, “
OFF
” will appear in the display, con-
rming that the NOTCH lter is no longer in opera-
tion.
Alternate touches of
[
]
, will switch the
NOTCH lter between on and o.
The bandwidth of the NOTCH lter
(
either narrow
or wide
)
may be adjusted using Menu item “
114
IF NOTCH WIDTH
”. The factory default setting is
“
WIDE
”.
The performance of the IF NOTCH lter is illus-
trated in Figure “
A
”, where the desired signal and
the interfering heterodyne are shown within the
IF passband. In Figure “B” the notching eect of
the IF NOTCH lter is illustrated as the
knob is rotated to eliminate the interfering het-
erodyne.
Desired Signal Desired Signal
QRM
(
Heterodyne
)
QRM
(
Heterodyne
)
IF BANDWIDTH IF BANDWIDTH
MULTI
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