Yaesu FT DX 1200, Руководство по эксплуатации

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Page 54
FT
DX
1200 O
PERATING
M
ANUAL
A B C
I
NTERFERENCE
R
EJECTION
WIDTH
(
IF DSP B
ANDWIDTH
)
T
UNING
(
SSB/CW/RTTY/DATA M
ODES
)
The IF WI ' TH tuning system allows you to vary the width of the ' S 3 IF passband, to reduce or eliminate interference.
0 oreover, the bandwidth may actually be
expanded
from its default setting, should you wish to enhance incoming sig-
nal ¿ delity when interference on the band is low.
1. 5 otate the [ WIDTH
] knob to the left or right to re-
duce the interference.
A
DVICE
:
The fre T uency display will show the bandwidth of
the IF passband for 3 seconds whenever the [ WIDTH
]
knob is turned.
[WIDTH] Knob
5 eferring to Figure “ B ”, you can see the default
bandwidth on the SSB mode.
By rotating the [
WIDTH
] knob to the left, the
bandwidth will narrow see Figure “ A ”, while
rotation of the [ WIDTH
] knob to the right, as
depicted in Figure “ C ”, will increase the band-
width.
A B C
The default bandwidths, and total bandwidth ad-
justment range, will vary according to the operat-
ing mode
SSB 0 ode 1.8 kH ] a 4.0 kH ] default .4 kH ] ).
CW 0 ode 00 H ] a .4 kH ] default .4 kH ] )
5 TTY '$ T $ 0 odes 00 H ] a .4 kH ] default
00 H ] )
Using IF SHIFT and WIDTH Together
The IF SHIFT and Variable IF WI ' TH features
together form a very effective interference- ¿ ght-
ing ¿ ltering system.
For example, in Figure “ A ”, you can see how
interference has appeared both on the high
and low sides of the desired signal.
5 otate the
[
WIDTH
] knob, the interference from one side
can be eliminated Figure “ B ”). 1 ext, rotate the
[
SHIFT
] knob to re-position the passband
Figure
“ C ”), the interference on the opposite side can be
removed, without re-introducing the interference
previously eliminated in Figure “
B ”.
A
DVICE
:
For best interference reduction, the WI ' TH and
SHIFT features are the primary tools you should
use, after narrowing the bandwidth
WI ' TH)
and or adjusting the center of the passband
SHIFT). The Contour control may then yield
additional signal-enhancement benefits on
the net residual bandwidth.
( ven more, the IF
12 TCH Filter described later) may also be
used, in conjunction with these ¿ lter systems, to
signi ¿ cant advantage.
WIDTH I
NDICATOR
IF BANDWIDTH IF BANDWIDTH IF BANDWIDTH
SHIFT SHIFT SHIFT
Desired Signal Desired Signal Desired Signal
QRM
QRM
QRM
QRM
QRM
QRM
IF BANDWIDTH IF BANDWIDTH IF BANDWIDTH