Function For Receive - Icom ic-718 Instruction Manual

 Function for receive
ï IF shift function
The IF shift function electronically narrows the pass-
band frequency of the intermediate frequency (IF) and
cuts out higher or lower frequency components of the
IF to reject interference. The function shifts the IF fre-
quency up to ±1.2 kHz in the SSB/CW/RTTY modes
and up ±250 Hz in the CW-narrow/RTTY narrow
modes. The IF shift is not selectable in the AM mode.
Both controls at
center position
SHIFT
IF center frequency
ï RIT function
The Receive Incremental Tuning (RIT) function com-
pensates for off-frequency signals. The function shifts
the receive frequency up to 1.2 kHz without shifting
the transmit frequency.
q Rotate the RIT control to shift the off-frequencies.
RIT RIT
• " " appears on the display.
• The transmit frequeny is not shifted.
ï Preamp
The preamp amplifi es received signals in the front
end circuit to improve the signal to noise (S/N) ratio
and sensitivity. Turn this function ON when receiving
weak signals.
➥ Push [P.AMP] to turn the preamp ON or OFF.
• The preamp functions below 1.59999 MHz, but sensi-
tivity may be reduced.
IF SHIFT OPERATION EXAMPLE
Cutting a lower
passband
SHIFT
Passband
Interference
Desired signal
w To cancel the RIT func-
RECEIVE AND TRANSMIT
• Adjust the [SHIFT] control for minimum interfer-
ence.
• When IF shift is used, the audio tone may
change.
• Set the IF shift control to the center position when
there is no interference.
Cutting a higher
passband
SHIFT
Desired signal
tion, rotate the RIT
control to the center po-
sition.
RIT RIT
• " " disappears.
Appears when the
preamp ON.
5
Passband
Interference
RIT off position
21