Using The Digital Twin Pbt; Ssb, Cw, Rtty, And Am Modes - Icom IC-705 Basic Manual

Using the Digital Twin PBT

SSB, CW, RTTY, and AM modes

To reject interference, the Digital Twin Passband
Tuning (PBT) narrows the IF passband width
by electronically shifting the IF frequency to
slightly above or below the IF center frequency.
The IC-705 uses the digital function using the
FPGA (Field Programmable Gate Array) filtering
method.
LEach mode memorizes the PBT setting.
1. Push to select "PBT1."
LEach push selects "PBT1" or "PBT2."
"1" (PBT1) or
"2" (PBT2)
2. Rotate to adjust the shift value.
• The passband width and shift value are
displayed.
LHold down
PBT setting.
3. Repeat steps 1 and 2 to adjust the shift
value for "PBT2."
LInformation
• To narrow the IF passband width, shift "PBT1" and
"PBT2" to the opposite direction from each other,
to narrow the overlapped area.
• To shift the IF left or right, set "PBT1" and "PBT2"
to the same value.
• The PBT is adjustable in 50 Hz steps in the SSB,
CW, and RTTY modes, and 200 Hz in the AM
mode. In this case, the center shift value changes
in 25 Hz steps in the SSB, CW, and RTTY modes,
and 100 Hz in the AM mode.
NOTE: While rotating
some noise. This comes from the FPGA and
does not indicate an equipment malfunction.
PBT is OFF
PBT1
PBT2
IF center frequency
for 1 second to clear the
, you may hear
Cutting
lower passband
PBT1
PBT2
Interference Desired
signal
RECEIVING AND TRANSMITTING
LInformation
• A dot "·" is displayed on the IF Filter Indicator
when you change the IF passband width, using
the Digital Twin PBT.
• Touch the filter icon for 1 second to display the
current passband width and shift value.
Opens the FILTER screen.
Passband Shift
width value
PBT1
PBT2
Cutting both higher and
PBT1
PBT2
Passband
Interference
4-4
IF center frequency
Passband center
frequency
SFT: Shift value
BW: Passband
width
lower passbands
Passband
Desired Interference
signal
4
4