Yaesu FTDX-9000D, Руководство по эксплуатации

Страница: 73 / 156

Page 71 FT
DX
9000D O
PERATION
M
ANUAL
SUB(VFO-B)
NTCH switch
MAIN(VFO-A)
NTCH knob
MAIN(VFO-A)
NTCH switch
SUB(VFO-B)
NTCH knob
MAIN (VFO-A) SUB (VFO-B)
SUB(VFO-B)
RX switch
IF N
OTCH
F
ILTER
O
PERATION
(
SSB/CW/RTTY/PKT/AM M
ODES
)
The IF Notch filter is a highly-effective system that allows you to slice out an interfering beat note or other carrier signal
from inside the receiver passband.
Main (VFO-A) Band IF Notch Operation
1. Press the Main (VFO-A) band NOTCH switch (# ).
The LED imbedded in the switch will glow Red to
confirm that the IF Notch filter has been engaged.
2. Rotate the Main (VFO-A) band’s NOTCH knob
(#
) to null out the interfering carrier.
To switch the IF Notch filter off, press the Main (VFO-A)
band’s NOTCH switch once more. The LED imbedded
in the switch will turn off, confirming that the IF Notch
filter is no longer operating.
Sub (VFO-B) Band IF Notch Operation
1. Press the Sub (VFO-B) band’s RX switch (# ) to
engage Dual Receive operation.
2. Press the Sub (VFO-B) band NOTCH switch (# ).
The LED imbedded in the switch will glow Orange to
confirm that the IF Notch filter has been engaged.
3. Rotate the Sub (VFO-B) band’s NOTCH knob
(#
) to null out the interfering carrier.
To switch the IF Notch filter off, press the Sub (VFO-B)
band’s NOTCH switch once more. The LED imbedded
in the switch will turn off, confirming that the IF Notch
filter is no longer operating.
Advice
H
The effect of the IF Notch filter may be observed on
the Audio Scope of the TFT (on the “Oscilloscope”
page). The Notch will be observed as a “dip” in the
noise platform observed. What's more, the “Waterfall”
display may be used to observe the effect of the IF
Notch filter, which will appear as a white area in the
colored background area. The tuning rate for the IF
Notch is somewhat slow, allowing precise adjustment,
so the use of the Waterfall display to confirm proper
adjustment is highly recommended.
H
The width of the IF Notch null may be adjusted using
Menu Item “RX DSP 082 IF-NOTCH-WIDTH.” Both
“Wide” and “Narrow” selections are available, with
“Narrow” providing the least disruption of the “de-
sired” signal.
H
Under the frequency display, you may also use the
Bar Display to show the position of the IF Notch. Use
Menu Item “DISPLAY 016 BAR DISPLAY SELECT”
to engage this function.
I
NTERFERENCE
R
EJECTION
(S
IGNALS WITHIN
3
KHZ
)
Note
When the NOTCH switch is pressed and held in for two
seconds, the center of the notch action will be reset to the
positions described below (mode-sensitive):
SSB/AM: The Notch will center at 1.5 kHz (center of
the receiver passband).
CW: The Notch will center on the frequency
programmed by the PITCH knob (#
).
The performance of the IF Notch filter is shown in
Figure (A), where the effect of rotation of the
NOTCH knob is depicted. In Figure (B) you can
see the notching effect of the IF Notch filter as you
rotate the NOTCH knob to eliminate the incom-
ing interference.
Desired Signal
QRM (Heterodyne)
NOTCH
IF BANDWIDTH IF BANDWIDTH
B A