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60
5
FUNCTION FOR RECEIVE
5
■
Twin PBT operation
General PBT (Passband Tuning) function electronically
narrows the IF passband width by shifting the IF fre-
quency to slightly outside of the IF
fi
lter passband to
reject interference. This transceiver uses the DSP cir-
cuit for the PBT function. Moving both
[TWIN PBT]
controls to the same position shifts the IF.
➥
The LCD shows the passband width and shift fre-
quency graphically.
➥
Push
[FILTER]
for 1 sec. to enter the filter set
mode. Current passband width and shift frequency
is displayed in the
fi
lter set mode screen.
➥
To set the
[TWIN PBT]
controls to the center posi-
tions, push
[PBT CLR]
for 1 sec.
The variable range depends on the passband width
and mode. The edge of the variable range is half of the
passband width, and PBT is adjustable in 25 or 50 Hz
steps. These controls function as an IF shift control
while in AM mode and when the RTTY
fi
lter is turned
ON. Only the inner control may function in this case.
IF shift is adjustable in 20/40 Hz steps in RTTY (RTTY
fi
lter is turned ON) or 150/300/500 Hz steps in AM.
•
[TWIN PBT]
should normally be set to the center posi-
tions (PBT setting is cleared) when there is no interfer-
ence.
• When PBT is used, the audio tone may be changed.
• Not available for FM mode.
• While rotating
[TWIN PBT]
, noise may occur. This comes
from the DSP unit and does not indicate an equipment
malfunction.
SFT
SFT
0
FIL2
FIL2
U S B
U S B
TX
TX
VFO
VFO
USB
USB
USB
USB
USB
USB
FIL2
FIL2
qr.qot.pp
qr.wpt.pp
14.100.00
14.100.00
14.100.00
14.100.00
1
1
VFO
VFO
BW
BW
2.4k
2.4k
ANT
ANT
1
METER
METER
Po
Po
P.AMP
P.AMP
1
ATT
ATT
OFF
OFF
qw
:
pp
12:00
Shows filter width, shifting value and condition
[TWIN PBT]
[PBT CLR]
[FILTER]
PBT OPERATION EXAMPLE
TWIN PBT
TWIN PBT
TWIN PBT
IF center frequency
Interference
Desired signal
Passband
Both controls at
center position
Cutting a lower
passband
Cutting both higher and
lower passbands
Interference
Interference
Desired signal
Passband