Icom IC-7700

4-22
D About BPSK and QPSK modes
BPSK and QPSK modes are available for PSK31.
•BPSK(BinaryPhaseShiftKeying)modeisthemost
commonly used mode.
•QPSK(QuadraturePhaseShiftKeying)modehas
error correction capability to provide better decoding
than BPSK mode in marginal condition. However,
more accurate tuning is required with QPSK mode,
due to the tight phase margin of QPSK.
q During PSK mode selection, push [DECODE]
F-3
to display the PSK decode screen.
w Push [<MENU1>]
F-1
to select PSK decode sec-
ond menu.
e Push [B/QPSK]
F-2
to toggle between BPSK and
QPSK mode alternately.
< MENU1 >
F-1
DECODE
F-3
B/QPSK
F-2
4
RECEIVE AND TRANSMIT
• PSK decode screen— BPSK mode
• PSK decode screen— QPSK mode
• Preamp (p. 5-10)
➥ Push [P.AMP] (MF3) several times to set the
preamp OFF, preamp 1 ON or preamp 2 ON.
•Hold down [P.AMP] (MF3) for 1 second to turn the
preamp function OFF.
•“P.AMP1”or“P.AMP2”appearswhenthepreamp1or
preamp 2 is ON.
• Attenuator (p. 5-10)
➥ Push [ATT] (MF4) several times to set the attenu-
ator in 6 dB steps.
•Hold down [ATT] (MF4) for 1 second to turn the
attenuator function OFF.
•“ATT”andattenuationlevelappearwhentheattenu-
ator is ON.
• Noise blanker (p. 5-17)
➥ Push
NB
to turn the noise blanker ON or OFF,
and then rotate [NB] control to adjust the thresh-
old level.
•Noise blanker indicator (above
NB
switch) lights
when the noise blanker is ON.
•Holddown
NB
for 1 second to enter noise blanker
set mode.
• Noise reduction (p. 5-18)
➥ Push
NR
to turn the noise reduction ON or
OFF.
• Rotate [NR] control to adjust the noise reduction level.
•Noisereductionindicator(above
NR
switch) lights
when the noise reduction is ON.
• Twin PBT (passband tuning) (p. 5-13)
➥ Rotate [TWIN PBT] controls (inner/outer).
•PBTindicator(above
PBT-CLR
switch) lights when
PBT is in use.
•Hold down
PBT-CLR
for 1 second to clear the set-
tings.
• AGC (auto gain control) (p. 5-12)
➥ Push [AGC] switch several times to select
AGC FAST, AGC MID or AGC SLOW.
➥ Push
AGCVR
to turn the AGC time constant
manual setting ON or OFF.
•Rotate[AGC]controltoadjustthetimeconstant.
• Manual notch filter (p. 5-19)
➥ Push
NOTCH
to turn the manual notch function
ON or OFF.
•Rotate [NOTCH] control to set the attenuating fre-
quency.
•Notchindicator(above
NOTCH
switch) lights when
the manual notch is ON.
• Fine tuning (p. 3-7)
➥ During PSK, make sure that the kHz tuning step
function is OFF (no “Z” indication), hold down
[TS] for 1 second.
•PSK maynotbedecodedcorrectlyusingthe10Hz
step tuning.
•
1
⁄4 function (p. 3-6)
➥ Push [1/4] to turn the
1
⁄4 function ON or OFF.
D Convenient functions for receive
l About the 5 MHz frequency band operation (USA version only)
See page 4-3 for details.