Twin Pbt Operation - Icom IC-7600 Instruction Manual

4
RECEIVE AND TRANSMIT

■ Twin PBT operation

<MODE> SSB/CW/RTTY/PSK/AM
PBT (Passband Tunng) electroncally narrows the IF
passband wdth by shftng the IF frequency slghtly
outsde of the IF flter passband to reject nterference.
The IC-7600 uses DSP for the PBT functon. Movng
both [TWIN-PBT] controls to the same poston shfts
the IF both above and below the receved frequency.
➥ The LCD shows the passband wdth and shft fre-
quency graphcally.
• The ndcator on the [PBT-CLR] swtch lghts when
PBT s n use.
➥ Push and hold
set screen. Current passband wdth and shft fre-
quency s dsplayed n the flter set screen.
➥ To set the [TWIN-PBT] controls to the center pos-
tons, push and hold
The varable range depends on the passband wdth
and mode. The edge of the varable range s half
of the passband wdth, and PBT s adjustable n 25
(SSB/CW/RTTY/PSK modes) or 100 Hz (AM mode)
steps.
• The [TWIN-PBT] controls should normally be set to
the center postons (PBT settng s cleared) when
there s no nterference.
• When PBT s used, the audo tone may be changed.
• Not avalable for FM mode.
• Whle rotatng the [TWIN-PBT] controls, nose may
occur. Ths comes from the DSP unt and does not
ndcate an equpment malfuncton.
• Push and hold [DEF] (F-4) for 1 sec. to select a
default value.
• PBT operation example
Both controls at
center position
IF center frequency
75
for 1 sec. to enter the flter
[FILTER]
for 1 sec.
[PBT-CLR]
PBT2
PBT1
Interference
Shows filter width, shifting value and condition
• Filter set screen
Cutting the lower
passband edge
PBT2
PBT1
Passband
Desired signal Interference
[TWIN-PBT]
PBT-CLR
F-4 FILTER
DEF
"SHARP" is selected.
Cutting both lower and
higher passband edges
PBT2
PBT1
Passband
Desired signal Interference