Yaesu FT-950, Руководство по эксплуатации, Страница: 42 / 132

Page 40 FT-950 O
PERATING
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ANUAL
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IAGRAM
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The FT-950 includes a wide range of special features to suppress the many types of interference that may be encountered
on the HF bands. However, real world interference conditions are constantly changing, so optimum setting of the controls
is somewhat of an art, requiring familiarity with the types of interference and the subtle effects of some of the controls.
Therefore, the following information is provided as a general guideline for typical situations, and a starting point for your
own experimentation.
The FT-950 ’s interference-fighting circuitry begins in its “RF” stages, and continues throughout the entire receiver section.
FT-950 allows configuration of the features described below.
R. FLT
(
IF Roofing Filters
)
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Three Roofing filters, of 15 kHz, 6 kHz, and 3 kHz band-
widths, are provided in the 69 MHz First IF, right after the
first mixer. These filters are automatically selected to pro-
vide narrow-band selectivity to protect the following IF
and DSP stages. The automatically selected filter, may be
manually changed by the operator, if desired, for special
operating circumstances.
CONTOUR Filter
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The DSP Contour filter has the unique ability to provide
either a null or a peak in tunable segments of the receiver
passband. You may suppress interference and excessive
frequency components on an incoming signal, or you may
peak those tunable frequency segments. The level of the
null or peak, and the bandwidth, over which it is applied,
are adjustable via the Menu.
IF SHIFT
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The passband center frequency of the IF DSP filter may
be moved up or down by adjusting this control.
IF WIDTH
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The width of the IF DSP filtering may be adjusted using
this control.
IF NOTCH
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The IF Notch filter is a high-Q notch filter that can signifi-
cantly reduce, if not eliminate, an interfering carrier.
DNF
(
Digital Notch filter
)
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When multiple interfering carriers are encountered during
reception, the Digital Notch Filter can significantly reduce
the level of these signals.
DNR
(
Digital Noise Reduction
)
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The DSP’s Digital Noise Reduction (DNR) feature uti-
lizes 15 different mathematical algorithms to analyze and
suppress different noise profiles encountered on the HF/
50 MHz bands. Choose the selection that provides the best
noise suppression, and allows the signal to rise up out of
the noise.
AGC
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The AGC system is highly adaptable to changing signal
and fading characteristics, making reception possible un-
der the most difficult conditions.
I
NTERFERENCE
R
EJECTION