Contour Control Operation - Yaesu FT-991 Operating Manual

i
nTerferenCe
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 enhances the sound and readability of a received signal.
1. Touch [ CONT ] displayed by pressing the F(M-
LIST) button to activate the Contour filter. The DSP
graphic display will illuminate and the current "null"
(or "peak") position of the Contour filter will appear
in the CONTOUR indicator on the display.
2. Rotate the MULTI knob to achieve the most natural-
sounding audio reproduction on the incoming signal.
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dvice
The display will show the Contour frequency when-
ever [ CONT ] on the LCD is touched.
3. To cancel Contour tuning, touch [ CONT ] on the
LCD.
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Alternate touches of [ CONT ] on the LCD will
switch the Contour filter between on and off.
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 The Contour filter level (either a null or a peak) may
be adjusted using Menu item "112 CONTOUR LEV-
EL". The factory default setting is for a null of –15
(dB).
 The bandwidth over which the Contour filter effect
is applied may be adjusted using Menu item "113
CONTOUR WIDTH". The factory default setting is
10. When the set value is increased, the bandwidth
becomes wider.
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By judicious use of the Contour filter, the "shoulder" of the passband response may be altered, or components may be
removed from within the passband, allowing the desired signal to rise above the background noise and interference in a
manner not obtainable with other filtering systems.
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r
eJeCTion
contour c
ontrol
o
perAtion
F(M-LIST) Button
Refer to Figure "B", this illustrates an "inden-
tation" of the Contour filter in the center of
the passband. The Contour filter places a low-
Q "notch" in the passband, per the settings of
Menu items "112 CONTOUR LEVEL" and "113
CONTOUR WIDTH" (referenced above). Counter-
clockwise rotation (to the left) of the MULTI
knob causes the notch to move toward a lower
frequency within the passband, while clockwise
rotation (to the right) causes the notch to move
toward a higher frequency within the passband.
By removing interference or unwanted frequency
components of the incoming signal, it is possible
to make the desired signal rise out of the back-
ground noise/interference, enhancing intelligibil-
ity.
A B
IF BANDWIDTH IF BANDWIDTH
MULTI MULTI
FT-991 O
C
IF BANDWIDTH
MULTI
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peraTing anual