D Convenient Functions For Receive; D About Bpsk And Qpsk Modes - Icom ic-7700 Instruction Manual

4
RECEIVE AND TRANSMIT

D Convenient functions for receive

• Preamp (p. 5-10)
➥ Push [P.AMP]
(MF3)
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] several times to set the attenu-
(MF4)
ator in 6 dB steps.
• Hold down [ATT]
attenuator function OFF.
• "ATT" and attenuation level appear when the attenu-
ator is ON.
• Noise blanker (p. 5-17)
➥ Push to turn the noise blanker ON or OFF,
NB
and then rotate [NB] control to adjust the thresh-
old level.
• Noise blanker indicator (above
when the noise blanker is ON.
• Hold down for 1 second to enter noise blanker
NB
set mode.
• Noise reduction (p. 5-18)
➥ Push to turn the noise reduction ON or
NR
OFF.
• Rotate [NR] control to adjust the noise reduction level.
• Noise reduction indicator (above
when the noise reduction is ON.
l About the 5 MHz frequency band operation (USA version only)
See page 4-3 for details.

D About BPSK and QPSK modes

< >
MENU1 B/QPSK
F-1 F-2
• PSK decode screen— BPSK mode
• PSK decode screen— QPSK mode
several times to set the
for 1 second to turn the
(MF4)
switch) lights
NB
switch) lights
NR
DECODE
F-3
• Twin PBT (passband tuning) (p. 5-13)
➥ Rotate [TWIN PBT] controls (inner/outer).
• PBT indicator (above
PBT is in use.
PBT-CLR
• Hold down
tings.
• AGC (auto gain control) (p. 5-12)
➥ Push [AGC] switch several times to select
AGC FAST, AGC MID or AGC SLOW.
AGC VR
➥ Push
manual setting ON or OFF.
• Rotate [AGC] control to adjust the time constant.
• Manual notch filter (p. 5-19)
NOTCH
➥ Push
ON or OFF.
• Rotate [NOTCH] control to set the attenuating fre-
quency.
• Notch indicator (above
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.
• ⁄ function (p. 3-6)
1
4
➥ Push [1/4] to turn the
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]
to display the PSK decode screen.
w Push [<MENU1>]
ond menu.
e Push [B/QPSK]
QPSK mode alternately.
4-22
PBT-CLR
switch) lights when
for 1 second to clear the set-
to turn the AGC time constant
to turn the manual notch function
NOTCH
switch) lights when
⁄ function ON or OFF.
1
4
F-1 to select PSK decode sec-
to toggle between BPSK and
F-2
F-3