5 FUNCTIONS FOR RECEIVE

■Twin PBT operation

[TWIN-PBT]

PBT-CLR

Shows filter width, shifting value and condition

•Filter set screen•PBT operation example

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-7700 uses DSP for the PBT function. Moving both [TWIN-PBT] controls to the same position shifts the IF for both high and low frequencies.

➥The LCD shows the passband width and shift fre- quency graphically.

•PBT indicator above PBT-CLRswitch lights when PBT is in use.

➥ Push and hold FILTER for 1 sec. to enter the filter set screen. Current passband width and shift frequency is displayed in the filter set screen.

➥To set the [TWIN-PBT] controls to the center posi- tions, push and hold PBT-CLRfor 1 sec.

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.

• [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.

Both controls at

Cutting a lower

 

Cutting both higher and

center position

passband

 

lower passbands

PBT1

PBT1

 

PBT1

PBT2

 

PBT2

PBT2

Passband

Passband

IF center frequency

Interference Desired signal

Interference Desired signal Interference

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