4-22
DD
Convenient functions for receive
DD
About BPSK and QPSK mode
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 [F-3•DECODE]
to display the PSK decode screen.
w Push [F-1•<MENU1>] to select PSK decode menu
2.
e Push [F-2•B/QPSK] to toggle between BPSK and
QPSK mode alternately.
• Preamp (p. 5-9)
➥ Push [P.AMP] several times to set the preamp
OFF, preamp 1 ON or preamp 2 ON.
• “P.AMP1” or “P.AMP2” appears when the preamp 1 or
preamp 2 is ON. Main and sub have independent
preamp controls.
• Attenuator (p. 5-9)
➥ Push [ATT] several times to set the attenuator in
6 dB steps.
• Pushing [ATT] for 1 sec. to set the attenuator in 3 dB
steps.
• “ATT” and attenuation level appear when the attenu-
ator is ON.
• Noise blanker (p. 5-17)
➥ Push [NB] switch to turn the noise blanker ON
and OFF, and then rotate [NB] control to adjust
the threshold level.
• Noise blanker indicator (above [NB] switch) lights
when the noise blanker is ON.
• Push [NB] for 1 sec. to enter noise blanker set mode.
• Twin PBT (passband tuning) (p. 5-12)
➥ Rotate [TWIN PBT] controls (inner/outer).
• Push [PBT CLEAR] to clear the settings.
• Noise reduction (p. 5-18)
➥ Push [NR] switch to turn the noise reduction ON
and OFF.
• Rotate [NR] control to adjust the noise reduction
level.
• Noise reduction indicator (above [NR] switch) lights
when the noise reduction is ON.
• AGC (auto gain control) (p. 5-11)
➥ 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 and OFF.
• Rotate [AGC] control to adjust the time constant.
• Fine tuning (p. 3-7)
➥ During PSK, make sure that the kHz tuning step
function is OFF (no “Z” indication), push [TS] for
1 sec.
• 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 and OFF.
4
RECEIVE AND TRANSMIT
• PSK decode screen— BPSK mode
• PSK decode screen— QPSK mode
