Contour Control Operation - Yaesu FT DX 3000 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. Press the [ CONT/APF ] button to activate the Con-
tour filter. The LED inside the [ CONT/APF ] button
glows orange and the current "null" (or "peak") po-
sition of the Contour filter will appear in the CON-
TOUR indicator on the display.
2. Rotate the [ CONT/APF ] knob to achieve the most
natural-sounding audio reproduction on the incom-
ing signal.
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The display will show the Contour frequency for 3
seconds whenever the [ CONT/APF ] knob is turned.
3. To cancel Contour tuning, press the [ CONT/APF ]
button momentarily.
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Alternate presses of the [ CONT/APF ] button will
switch the Contour filter between on and off.
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 The Contour filter selection will be memorized inde-
pendently on each VFO stack of VFO-A and VFO-B.
 The Contour filter level (either a null or a peak) may
be adjusted using Menu item "108 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 "109
CONTOUR WIDTH". The factory default setting is
10.
Q p :
uicK oiNt
The steep slopes of the DSP filtering, when adjusted aggressively, can impart an unnatural sound to an incoming sig-
nal. Often, a narrow bandwidth is not the key to improving copy; the incoming signal itself may have undesirable or
excessive frequency components, especially in the low frequency range around 100-400 Hz. 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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[CONT/APF] Knob [ CONT/APF ] Button
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Refer to Figure "B", this illustrates an "indenta-
tion" 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 "108 CONTOUR LEVEL" and "109 CON-
TOUR WIDTH" (referenced above). Counter-
clockwise rotation (to the left) of the [ CONT/
APF ] knob causes the notch to move toware
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 background noise/interference, enhancing
intelligibility.
A B
IF BANDWIDTH IF BANDWIDTH
CONT/APF CONT/APF
FT 3000 O
DX
NdicAtoR
C
IF BANDWIDTH
CONT/APF
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peraTing anual