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REJECTING INTERFERENCE 9
Press and hold [IF FIL] to momentarily display each
setting value of the DSP fi lter band as follows:
SSB/ SSB-DATA, AM/ FM mode:
High cut Frequency > Low cut Frequency
CW/ SSB/ SSB-DATA mode:
Shift Frequency > Bandwidth
FSK mode: Bandwidth only
■
Filter control in SSB/ SSB-DATA mode (High/Low
and Width/Shift)
In SSB and SSB-DATA modes, you can switch the
Hi/Low cut operation and the Width/Shift operation.
1 Press [MENU], then press [Q-M.IN]/ [Q-MR] or
turn the MULTI/CH control to select Menu No.
28 (SSB) or 29 (SSB-DATA).
2 Press [M.IN]/ [SCAN (SG.SEL)] to select the
fi lter control type HI/LO (1) or WIDTH/SHIFT
(2).
AUTO NOTCH FILTER (SSB)
The Auto Notch fi lter automatically locates and
attenuates any single interfering tone within the
receive pass band. This function operates digitally
at the IF fi lter level, hence it can affect your S-meter
reading and may also affect (slightly attenuate) your
desired signal. However, controlling the AGC level by
notching out the strong interfering beat signals could
bring up the desired SSB signal that is covered by the
interfering beat signal. If the interfering tone is weak,
you may fi nd that Beat Cancel eliminates them more
effectively.
Before
Interfering
tones
After
Receive pass band
Desired
signal
Press and hold [BC (A.NOTCH)] to toggle the Auto
Notch Filter ON and OFF.
• “ ” appears when this function is ON.
• The interfering beat signals are notched out.
■ Auto Notch Tracking Speed
If the interfering beat signals change the tone
frequency randomly, you can adjust the Auto Notch
tracking speed.
1 Press [MENU], then press [Q-M.IN]/ [Q-MR] or
turn the MULTI/CH control to select Menu No. 30.
2 Press [M.IN]/ [SCAN (SG.SEL)] to select the
level from FIX (0), and 1 to 4.
• Level 1 is the slowest beat tone tracking
speed and Level 4 is the fastest. FIX
terminates the beat tone tracking. Adjust
this parameter manually to remove the beat
signal if necessary.
3 Press [MENU] to exit Menu mode.
MANUAL NOTCH FILTER (SSB/ CW/ FSK)
Use manual notch when you want to vary the width of
the notch while verifying the interfering signal.
1 Press [NOTCH (WIDE)] to toggle the Manual
Notch Filter ON and OFF.
• “
” appears when this function is ON.
2 Turn the NOTCH control to adjust to the point
where beat noise just disappears.
■ Notch Filter Bandwidth
Press and hold [NOTCH (WIDE)] to toggle the
Notch fi lter bandwidth between NORMAL and
WIDE.
• “ ” appears when the Notch fi lter
bandwidth is set to WIDE.
BEAT CANCEL (SSB/ AM)
Two types of Beat Cancel DSP fi lters are available.
Beat Cancel 1 (BC1) is effective for removing a weak
beat or continuous beat signals. Beat Cancel 2 (BC2)
is effective for removing intermittent beat signals, such
as CW signals.
Before
Interfering
tones
After
Filter pass band (AF)
Desired
signal
Press [BC (A.NOTCH)] to cycle through Beat Cancel
1, Beat Cancel 2, and OFF.
• “
” or “ ” appears when the Beat Cancel
function is ON.
• The interfering beat signals are removed.
NOISE REDUCTION (ALL MODES)
This transceiver provides 2 types of Noise Reduction
functions (NR1 and NR2) for reducing random noise
which interferes with the desired signal.
NR1 differs, depending on the reception mode.
When receiving a voice call in SSB/ FM/ AM mode,
noise reduction uses a spectrum subtraction system.
When receiving a non-voice call in CW/ FSK mode,
noise reduction uses a LMS adaptive fi lter which
emphasizes the periodic signal.
NR2 uses a SPAC format, which extracts a periodic
signal from within the received signal.
Press [NR (LEV)] to cycle between NR1, NR2, and
OFF.
• “ ” or “ ” appears, depending on which
noise reduction fi lter is selected.