Using The Digital Twin Pbt - Icom IC-905 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-905
uses the digital function using the FPGA (Field
Programmable Gate Array) filtering method.
L Each mode memorizes the PBT setting.
1. Push to select "PBT1."
L Each 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.
• Hold down
setting.
3. Repeat steps 1 and 2 to adjust the shift value for
"PBT2."
L Information
• To narrow the IF passband width, shift "PBT1" and "PBT2"
to the opposite direction from each other, to narrow the
overlapped area.
• To use as the IF Shift function, 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. 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
noise. This comes from the FPGA and does not
indicate an equipment malfunction.
Default value
PBT1
PBT2
IF center frequency
for 1 second to clear the PBT
, you may hear some
lower passband
PBT1
PBT2
Interference
RECEIVING AND TRANSMITTING
L Information
• 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 width
PBT1
PBT2
Cutting
PBT1
PBT2
Passband
Desired Interference
signal
4-5
Shift value
IF center frequency
Passband center
frequency
SFT: Shift value
BW: Passband
width
Cutting both higher and
lower passbands
Passband
Desired Interference
signal
4
4