Kenwood TS-990S - Manual (Page 147)

REJECTING INTERFERENCE 6
6-9
Index Contents
AUDIO PEAK FILTER WHILE IN FSK MODE
While the transceiver receives a signal in FSK mode,
the audio peak filter allows the mark frequency and
space frequency each to have a peak, thus reducing the
occurrence of garbled characters and increasing the
readability of the signal. The audio peak filter supports not
only high-tone signals with a mark frequency of 2125 Hz
but also low-tone signals with a mark frequency of 1275
Hz. {page 5-46}
[FSK/PSK/REV]
[APF/SEL] (S) [APF/SEL] (M)
1 Press [FSK/PSK/REV] to select FSK mode.
2 Press [APF/SEL] (M) or [APF/SEL] (S) to enable the
audio peak filter for the selected band.
While the audio peak filter is active, the "APF/SEL" (M) or
"APF/SEL" (S) LED lights green.
Note:
◆ If the shift width for RTTY mode exceeds 170 Hz, the audio peak
filter for the selected band cannot be enabled
◆ The audio filter for use in FSK mode does not process the signal to
be demodulated internally.
NOISE BLANKER
The noise blanker suppresses “crunching” pulse noise.
The transceiver incorporates two types of noise blanker;
Noise Blanker 1 (NB1) for analog signal processing, and
Noise Blanker 2 (NB2) for digital signal processing at the
IF stage by means of a DSP. You can select either NB1 or
NB2 as desired depending on the noise status. Both can
be enabled at the same time.
Note:
◆ In FM mode, you cannot use Noise Blanker.
◆ Noise is suppressed more effectively if a larger value is configured,
but there may be some effect on the received signal.
[F1] [F7]
[ESC] [NB2]
[MULTI/CH]
[NB1]
[NB1/SEL] [NB2/SEL]
[NB2] [NB1]
■ Activating or deactivating the Noise Blankers for
the main band
1 Press [NB1] or [NB2].
• Noise Blanker 1 or 2 for the main band is activated or
deactivated.
• While Noise Blanker 1 or Noise Blanker 2 is active, "NB1"
or "NB2" appears on the upper left side of the main screen.
While both Noise Blanker 1 and Noise Blanker 2 are active,
"NB1 2" appears on the upper left side of the main screen.
• Pressing the key again deactivates Noise Blanker for the
main band.
■ Activating or deactivating the Noise Blankers for
the sub band
1 Press [NB1/SEL] or [NB2/SEL].
• Noise Blanker 1 or Noise Blanker 2 for the sub band
becomes active or inactive.
• While Noise Blanker 1 or Noise Blanker 2 is active, "NB1"
or "NB2" appears on the upper left side of the main screen.
While both Noise Blanker 1 and Noise Blanker 2 are active,
"NB1 2" appears on the upper left side of the main screen.
• To deactivate Noise Blanker 1 or Noise Blanker 2 for the
sub band, press the key again.
■ Adjusting the Noise Blanker levels for the main
band.
1 Rotate the NB1 or NB2 control.
• You can adjust the level of NB1 or NB2.
• Rotating the NB1 or NB2 control clockwise suppresses
noise.