ICOM 361500 Manuale Utente

7-5

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In general PBT (Passband Tuning) electronically nar-
rows the IF passband width by shifting the IF frequen-
cy to slightly outside of the IF filter passband to reject 
interference. The IC-7850 uses DSP for the PBT func-
tion. Moving both [TWIN PBT] controls to the same po-
sition shifts the IF.

➥

  The LCD shows the passband width and shift fre-

quency graphically.

➥

  Hold down [FILTER] for 1 second to enter the filter 

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, hold down [PBT CLR] for 1 second.

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 Hz steps 
in the SSB/CW/RTTY/PSK modes, and 100 Hz in the 
AM mode. 

•  [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.

[EXIT/SET]

[PBT CLEAR]

[TWIN PBT] control

[FILTER]

[PBT CLEAR] indicator

• “FILTER” display when operating [TWIN PBT]

•  About Passband width and Shift value on the screen

PBT1
PBT2

IF center frequency
Passband’s center frequency

SFT: Shift value

BW: Passband width

• When operating [TWIN PBT]

Filter width Shifting value

Passband width
(Duplicated with PBT1 and PBT2)

Selected 

IF filter

Passband

Passband

IF center frequency

Desired signal

Interference

Interference

Interference

Desired signal

PBT2

PBT1

PBT2

PBT1

PBT2

PBT1

Both controls at 
center position

Cutting a lower 
passband

Cutting both higher and 
lower passbands

• PBT operation example