Yaesu FTdx5000MP, Руководство по эксплуатации

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Page 58 FT
DX
5000 O
PERATING
M
ANUAL
CONTOUR C
ONTROL
O
PERATION
The Contour Filter system produces a gentle perturbation of the IF filter passband. The different frequency components of
the signal can be suppressed or enhanced, thus improving the sound and/or readability of the received signal.
I
NTERFERENCE
R
EJECTION
(
S
IGNALS WITHIN
3
KHZ
)
VFO-A Contour Operation
Press the (
VFO-A
)[
CONT/APF
] button. The button
will glow red and the position of the “null” (or “Peak”)
of the contour filter will be indicated in the
SUB DIS-
PLAY- II window. The ( VFO-A
)[
SELECT
] knob will
now function as the contour knob.
Rotate the ( VFO-A
)[
SELECT
] knob to achieve the
most pleasing audio reproduction of the incoming sig-
nal.
Press the (
VFO-A
)[
RESET
] button in briefly, to
quickly move the “null” (or “Peak”) position to center.
To cancel Contour tuning, press the (
VFO-A )[ CONT/
APF
] button once more.
A
DVICE
:
The contour filter null or peaking level may be adjusted
using Menu item “
112 RDSP CNTR LV ”. The factory
default null setting is “ –15 ” (dB).
The bandwidth over which the contour null or peaking
affect is applied may be adjusted using Menu item “
113
RDSP CNTR WI
”. The factory default setting is “
10
”.
You may select the display pattern shown in the
SUB
DISPLAY window from three patterns via Menu item
“ 019 DISP SELECT ”. See page 122 for details.
When the optional DMU-2000 Data Management Unit
is connected, the Audio Scope (on the DMU-2000 “Os-
cilloscope” page) is particularly useful when adjusting
the Contour controls. You can see the affect of the
Contour system on the signal levels, and the position
of the null/peak with respect to frequency components
of interest. On the Audio Scope, you may visually ob-
serve the affect of the Contour Controls while listen-
ing to the signal, this will help build your intuition on
how best to use Contour tuning in the future.
VFO-B Contour Operation
Press the (
VFO-B
)[
CONT/APF
] button. The button
will glow red and the current “null” (or “Peak”) posi-
tion of the contour filter will be indicated in the
SUB
DISPLAY- III window. The ( VFO-B
)[
SELECT
] knob
will now function as the contour knob.
Rotate the ( VFO-B
)[
SELECT
] knob to achieve the
most natural-sounding audio reproduction of the in-
coming signal.
Press the (
VFO-B
)[
RESET
] button in briefly, to
quickly move the “null” (or “Peak”) position to center.
To cancel Contour tuning, press the (
VFO-B )[ CONT/
APF
] button once more.
(VFO-A)[SELECT] Knob (VFO-B)[SELECT] Knob
(VFO-B)[CONT/APF] Button
[RESET] Button
(VFO-A)[CONT/APF] Button
[RESET] Button
N
OTE
:
When receiving a single tone signal, such as CW, with the
Contour gain set to a high level (adjusted by Menu item
“
112 RDSP CNTR LV ”), the receive signal may occa-
sionally be heard at a low volume, even if the AF GAIN
knob is set to minimum.
Q
UICK
P
OINT
:
When adjusted aggressively, the steep slopes of the DSP
filtering can impart an unnatural sound to an incoming sig-
nal. Often, a narrow bandwidth is not the key to improved
copy. The incoming signal itself may have undesirable or
excessive frequency components, especially in the low fre-
quency range around 100-400 Hz. By judicious use of the
Contour filter, the “shoulder” of the passband response
may be altered, or components removed from within the
passband, allowing the desired signal to rise above the
background noise and interference in a manner not ob-
tainable with other filtering systems.