Spectrum DSP M2 User Manual page 33

RX NB Setting - This is the same as the "NB" setting on the main screen. This
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adjusts the "strength" of the noise blanker, with "0" being off.
The noise blanker takes a significant amount of processor horsepower, so
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some "slowing" of responses should be expected when it is active,
particularly if DSP is turned on at the same time!
The noise blanker is disabled when the menu is displayed, when in AM
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mode or if a wide bandwidth is selected.
RX/TX Freq Xlate – This enables the mathematical translation of the receive signals,
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shifting them from "zero" (e.g. around DC) to + or – 6 kHz. This feature can reduce
issues related to direct-conversion receivers such as audio feedback, power supply
noise and other noise sources that can degrade receiver performance. The selectable
options are:
OFF - This is the original operation of the transceiver with the receive (and
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transmit) signals operating at and around zero Hz (e.g. baseband operation.)
RX LO HIGH - In this mode the signals are shifted below zero Hz by 6 kHz,
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requiring that the local oscillator be shifted up by the same amount. The
received signals are tuned at the first graticule left of center on the spectrum
scope.
RX LO LOW - In this mode the signals are shifted above zero Hz by 6 kHz,
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requiring that the local oscillator be shifted down by the same amount. The
received signals are tuned at the first graticule right of center on the spectrum
scope. For various reasons (e.g. the use of USB on higher bands where
the potential for zero-HZ interference is highest) the use of "RX LO LOW"
is recommended for best performance!
For more information, refer to the section about Frequency Translation near the
end of this document.
Transmit Audio related items: (Set-up dependent)
Mic/Line Select - This selects whether the Microphone or the LINE input is to be used
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for transmit audio in the SSB mode. This is the same function as pressing-and-holding
button M3 when in a voice mode.
Mic Input Gain - This is used to adjust the microphone input gain to adjust the drive in
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SSB mode. It is recommended that the AUDio meter be used, setting this parameter
for audio peaks above "0dB". This setting cannot be adjusted if the MIC input is not
selected.
Line Input Gain - This is used to adjust the line input gain to adjust the drive in SSB
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mode. It is recommended that the AUDio meter be used, setting this parameter for
audio peaks above "0dB". This setting cannot be adjusted if the LINE input is not
selected.
ALC Release Time - This adjusts the release (decay) time of the ALC. A value of 10
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is offers modest compression while values of 5 or lower offer fairly aggressive
compression. See the section about the adjustment of the ALC/Compressor. This
setting will be displayed in RED and not adjustable unless "TX Audio Compress" is set
to "SV".
TX PRE ALC Gain - This is a post-filter, pre-ALC gain setting in the TX audio path
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Spectrum DSP M2 User Manual V1.1
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