Kenwood TS-570D User Manual - Page 44

Rejecting Interference, Noise Reduction, Beat Cancel

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9 REJECTING INTERFERENCE ■ CW/ FSK Modes 1 Select CW or FSK mode. 2 Press [FILTER]. • The current filter selection appears. 3 Turn the MULTI/CH control clockwise to widen the bandwidth, or counterclockwise to narrow the bandwidth. Interfering signal Desired Interfering signal signal 4 Press [FILTER] to complete the setting. Mode Bandwidth Selections (Hz) CW 50, 80, 100, 150, 200, 300, 400, 500, 600, 1.0 k, 2.0 k FSK 250, 500, 1.0 k, 1.5 k Default (Hz) 600 1.5 k Depending on which bandwidth you select for the DSP filter and which type of optional filter you install, the wide IF filter or the narrow IF filter will automatically be selected. Optional Filter Mode DSP Filter Bandwidth IF Filter Bandwidth 2.0 kHz CW YK-88SN-1 1.0 kHz or lower SSB 1.5 kHz (1.8 kHz) FSK 250 Hz, 500 Hz, 1.0 kHz Wide Narrow Wide Narrow YK-88C-1 CW (500 Hz) CW FSK 1.0 kHz, 2.0 kHz 600 Hz or lower 1.0 kHz, 1.5 kHz 250 Hz, 500 Hz Wide Narrow Wide Narrow YK-88CN-1 300 Hz or higher CW CW 50 Hz, 100 Hz, (270 Hz) 200 Hz Wide Narrow BEAT CANCEL Beat Cancel uses an adaptive filter and attenuates more than one cyclic interference within the receive pass band. The adaptive filter changes its characteristics according to the nature of the signal being received at a given moment. You can use Beat Cancel when in SSB, FM, or AM mode. Interfering tones Receive pass band Before 38 After Desired signal Press [B.C.] to toggle Beat Cancel ON or OFF. • "BEAT CANCEL" appears when the function is ON. Note: While receiving intermittent CW signals, the transceiver sounds clicks. This does not indicate a malfunction. If attenuation is not satisfactory, press [B.C.] for 1 second or longer to enhance the attenuation effect; a beep sounds, but no change occurs on the display. Pressing [B.C.] for 1 second or longer again restores the original attenuation level. Note: ◆ The Enhanced Beat Cancel setting is cleared when the power to the transceiver is turned OFF. ◆ Enhanced Beat Cancel may adversely affect desired signals slightly because of its stronger effect. NOISE REDUCTION This transceiver provides two types of Noise Reduction functions, 1 and 2, for reducing random noise which interferes with the desired signal. Just trying them both is the easiest way to judge which function works more effectively under the current condition. Normally select Noise Reduction 1 in SSB mode and select Noise Reduction 2 in CW mode. Note: Using Noise Reduction 2 in SSB mode may lower the clarity of signals or induce pulse noise depending on conditions. Press [N.R.] to toggle between Noise Reduction 1, Noise Reduction 2, and OFF. • "N. R. 1" or "N.R. 2" appears depending on which function is selected. Note: A different selection can be made between two groups of modes; one group includes SSB, FM, and AM, and the other group includes CW and FSK. So you need not change the selection each time you switch modes between the two groups. ■ Changing NR1 Performance Use Menu No. 51 to change the effect of Noise Reduction 1. Switch Noise Reduction 1 ON, then select level 1 to 9 in this menu while receiving signals. The default is "Auto"; this selection provides an optimum effect according to the strength of the received signal. Note: ◆ Using a high NR1 level and Beat Cancel simultaneously may cause noise to stand out; this does not indicate a malfunction. ◆ When changing the NR1 level in the menu, you will hear sound momentarily caused by an internal operation change; this does not indicate a malfunction. ■ Setting NR2 Time Constant You can change the correlation time for Noise Reduction 2. When in SSB, select the correlation time that allows you to hear signals with more clarity. When receiving CW, it is best to select the longest correlation time that allows reliable reception. The longer the correlation time, the better S/N. Access Menu No. 12 and select 7.5 ms or 20 ms. The default is 20 ms.

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38
9
REJECTING INTERFERENCE
Press
[B.C.]
to toggle Beat Cancel ON or OFF.
°
°BEAT CANCEL± appears when the function is ON.
Note:
While receiving intermittent CW signals, the transceiver
sounds clicks.
This does not indicate a malfunction.
If attenuation is not satisfactory, press
[B.C.]
for
1 second or longer to enhance the attenuation effect; a
beep sounds, but no change occurs on the display.
Pressing
[B.C.]
for 1 second or longer again restores
the original attenuation level.
Note:
◆
The Enhanced Beat Cancel setting is cleared when the power to
the transceiver is turned OFF.
◆
Enhanced Beat Cancel may adversely affect desired signals
slightly because of its stronger effect.
NOISE REDUCTION
This transceiver provides two types of Noise Reduction
functions, 1 and 2, for reducing random noise which
interferes with the desired signal.
Just trying them both
is the easiest way to judge which function works more
effectively under the current condition.
Normally select
Noise Reduction 1 in SSB mode and select Noise
Reduction 2 in CW mode.
Note:
Using Noise Reduction 2 in SSB mode may lower the clarity
of signals or induce pulse noise depending on conditions.
Press
[N.R.]
to toggle between Noise Reduction 1,
Noise Reduction 2, and OFF.
²
°N. R. 1± or °N.R. 2± appears depending on which
function is selected.
Note:
A different selection can be made between two groups of
modes; one group includes SSB, FM, and AM, and the other group
includes CW and FSK.
So you need not change the selection each
time you switch modes between the two groups.
■
Changing NR1 Performance
Use Menu No. 51 to change the effect of Noise
Reduction 1.
Switch Noise Reduction 1 ON, then
select level 1 to 9 in this menu while receiving
signals.
The default is °Auto±; this selection provides
an optimum effect according to the strength of the
received signal.
Note:
◆
Using a high NR1 level and Beat Cancel simultaneously may
cause noise to stand out; this does not indicate a malfunction.
◆
When changing the NR1 level in the menu, you will hear
sound momentarily caused by an internal operation change;
this does not indicate a malfunction.
■
Setting NR2 Time Constant
You can change the correlation time for Noise
Reduction 2.
When in SSB, select the correlation
time that allows you to hear signals with more clarity.
When receiving CW, it is best to select the longest
correlation time that allows reliable reception.
The
longer the correlation time, the better S/N.
Access Menu No. 12 and select 7.5 ms or 20 ms.
The default is 20 ms.
■
CW/ FSK Modes
1
Select CW or FSK mode.
2
Press
[FILTER]
.
²
The current filter selection appears.
3
Turn the
MULTI/CH
control clockwise to widen
the bandwidth, or counterclockwise to narrow the
bandwidth.
4
Press
[FILTER]
to complete the setting.
Depending on which bandwidth you select for the
DSP filter and which type of optional filter you install,
the wide IF filter or the narrow IF filter will
automatically be selected.
BEAT CANCEL
Beat Cancel uses an adaptive filter and attenuates more
than one cyclic interference within the receive pass
band.
The adaptive filter changes its characteristics
according to the nature of the signal being received at a
given moment.
You can use Beat Cancel when in SSB,
FM, or AM mode.
Interfering
tones
Receive pass band
Desired
signal
Before
After
Interfering
signal
Desired
signal
Interfering
signal
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