Twin Pbt Operation - Icom IC-i7410 Instruction Manual

5
FUNCTIONS FOR RECEIVE

■ Twin PBT operation

(Mode: SSB/CW/RTTY/AM)
To reject interference, PBT (Passband Tuning) elec-
tronically narrows the IF passband width by shifting the
IF frequency slightly outside of the IF filter passband.
The IC-7410 uses DSP for the PBT function. Moving
both [TWIN-PBT] controls shift the IF passband cen-
ter frequency both above and below the received fre-
quency.
➥ The LCD graphically shows the passband width and
frequency shift.
➥ Hold down [FILTER] for 1 second to display the "FIL"
screen (Filter). Current passband width and fre-
quency shift are displayed in the "FIL" screen.
➥ Hold down [PBT-CLR] for 1 second to set the IF
frequency to the center position.
• The "dot" disappears.
The PBT is adjustable in 50 Hz steps in the SSB, CW
and RTTY modes, and 200 Hz in the AM mode.
In this time, the shift value changes in 25 Hz steps in
the SSB, CW and RTTY modes, and 100 Hz in the AM
mode.
• The [TWIN-PBT] controls should normally be set
to the center positions when there is no interfer-
ence. The PBT setting should be cleared.
• When the PBT is used, the audio tone may
change.
• The controls do not function in the FM mode.
• While rotating the [TWIN-PBT] controls, noise may
occur. This comes from the DSP unit and does not
indicate an equipment malfunction.
• Pushing [PBT-CLR] displays the filter passband
width and shift value for 2 seconds on the function
display.
PBT OPERATION EXAMPLE
Both controls in the center
positions (or hold down
[PBT-CLR] for 1 second.)
IF center frequency
59
PBT2
PBT1
Interference
M1
A G C
Passband width and shift
value are displayed while
[TWIN PBT] is used.
• "FIL" screen (Filter) display
FIL
B W
Shows the selected filter and passband width.
• While adjusting the PBT setting
FIL
B W
• About Passband width and Shift value
on the screen
IF center
frequency
Cutting the lower
passband edge
PBT2
PBT1
Passband
Desired signal Interference
[PBT-CLR]
[FILTER]
B 2 . 3 K S + 2 5
T B W
Appears when pass-
band is shifted.
S S B - 2
B 2 . 4 K S 0
S H A R P
S S B - 2
B 2 . 0 K S + 2 0 0
S H A R P
Appears when the passband is shifted.
: Passband width
B
Passband's
center frequency
: Shift value
S
Cutting both lower and
higher passband edges
PBT2
Passband
Desired signal Interference
[TWIN-PBT]
S C P
2 . 4 K
2 . 4 K
PBT1