If Shift Operation (Ssb/Cw/Rtty/Pkt Modes) - Yaesu FT-991 Operating Manual

iF ShiFt o
IF SHIFT permits moving the DSP filter passband higher or lower, without changing the pitch of the incoming signal,
and thus reduces or eliminates interference. Because the tuned carrier frequency is not varied, there is no need to re-tune
the operating frequency to eliminate the interference. The total passband tuning range for the IF SHIFT system is ±1.2
kHz.
1. Press the F(M-LIST) button to display the function
menu list. Touch [ SHIFT ] to reduce the interference.
The MULTI knob functions as the SHIFT adjustment
knob.
SHIFT indicator
SHIFT level indicator
2. Rotate the MULTI knob to the left or right to reduce
interfering signals.
A :
dvice
 Rotate the MULTI knob to display the shift offset
of the IF filter (−1,200 Hz to +1,200 Hz) below
the [ SHIFT ] indicator.
 The level indicator shows the shift offset direc-
tion for your reference.
Referring to Figure "A", note the depiction of the
IF DSP filter as the thick line, with MULTI knob
in the 12 o'clock position. In Figure "B", an in-
terfering signal has appeared inside the original
passband. In Figure "C", you can see the effect
of rotating the MULTI knob. The interference
level is reduced by moving the filter passband so
that the interference is outside of the passband.
A
Desired Signal Desired Signal
QRM
IF BANDWIDTH IF BANDWIDTH
MULTI
FT-991 O
peraTing
i
nterference
( SSb/cW/rtty/pkt M
perAtion
B C
Desired Signal
QRM
IF BANDWIDTH
MULTI MULTI
M
anual
r
eJection
)
odeS
F(M-LIST) Button
MULTI Knob
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