29
FT-891 Advance Manual
Interference Rejection
CONTOUR Control Operation
The Contour filter system provides a gentle perturbation of the IF filter passband. The
Contour is set to either suppress, or boost specific frequency components, and thus
enhance the sound and readability of a received signal.
1. Press the [
F
] key repeatedly, to find the
“FUNCTION-2” list screen.
2. Rotate the
MULTI
function knob to select
“CNT”.
3. Press the
MULTI
function knob, and then ro-
tate it to achieve the most natural sounding
audio reproduction of the incoming signal.
4. When the adjustment is completed, press
and hold the [
F
] key for one second to exit
the “FUNCTION-2” list screen and resume
normal operation.
r
To set the CONTOUR Operation will be set to “OFF”:
1. Press the [
F
] key repeatedly, to find the “FUNCTION-2” list screen.
2. Rotate the
MULTI
function knob to select [
CNT
], then press the
MULTI
function knob.
3. Press and hold the [
F
] key for one second to exit the “FUNCTION-2” list screen
and resume normal operation.
r
CONTOUR function may be assigned to the [A], [B] or [C] key. Refer to “Changing the
function assigned to the [A]/[B]/[C] keys” in the FT-891 Operating Manual.
r
The Contour function attenuation and bandwidth can be set in Menu Mode “
12-02
[
CONTOUR LEVEL
]” and “
12-03
[
CONTOUR WIDTH
]” (refer to the instructions on
the below).
Refer to Figure (B), this illustrates a “dip” in
the center of the Contour filter passband.
The Contour filter places a low-Q “notch” in
the passband, corresponding to the settings
of Menu Mode “
12-02
[
CONTOUR LEVEL
]”
and “
12-03
[
CONTOUR WIDTH
]”. Counter-
clockwise rotation of the
MULTI
function knob
causes the notch to move toward a lower fre-
quency within the passband, while clockwise
rotation causes the notch to move toward a
higher frequency within the passband.
(A)
(B)
(C)
IF BANDWIDTH IF BANDWIDTH IF BANDWIDTH
MULTI
MULTI
MULTI
By removing interference or unwanted frequency components of the incoming signal, it is pos-
sible to make the desired signal rise out of the background noise/interference, and significantly
enhance intelligibility.
