Twin Pbt Operation - Icom IC-7600 Instruction Manual

4
RECEIVE AND TRANSMIT

Twin PBT operation

<MODE> SSB/CW/RTTY/PSK/AM
PBT (Passband Tuning) electronically narrows the IF
passband width by shifting the IF frequency slightly
outside of the IF filter passband to reject interference.
The IC-7600 uses DSP for the PBT function. Moving
both [TWIN-PBT] controls to the same position shifts
the IF both above and below the received frequency.
The LCD shows the passband width and shift fre-
quency graphically.
• The indicator on the [PBT-CLR] switch lights when
PBT is in use.
Push and hold
set screen. Current passband width and shift fre-
quency is displayed in the filter set screen.
To set the [TWIN-PBT] controls to the center posi-
tions, push and hold
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
(SSB/CW/RTTY/PSK modes) or 100 Hz (AM mode)
steps.
• The [TWIN-PBT] controls should normally be set to
the center positions (PBT setting is cleared) when
there is no interference.
• When PBT is used, the audio tone may be changed.
• Not available for FM mode.
• While rotating the [TWIN-PBT] controls, noise may
occur. This comes from the DSP unit and does not
indicate an equipment malfunction.
• PBT operation example
Both controls at
center position
IF center frequency
75
for 1 sec. to enter the filter
[FILTER]
for 1 sec.
[PBT-CLR]
PBT1
PBT2
Interference
Shows filter width, shifting value and condition
• Filter set screen
Cutting the lower
passband edge
PBT1
PBT2
Passband
Desired signal Interference
[TWIN-PBT]
PBT-CLR
FILTER
Cutting both lower and
higher passband edges
PBT1
PBT2
Passband
Desired signal Interference