Robotron Pty Ltd G9P 用户手册
WiNRADiO G39DDC User’s Guide
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2. If the AGC is enabled and the sound is distorted despite the volume being
turned down, make sure that the AGC reference level is not set too high. If the
volume is too low, try to increase the AGC reference level.
turned down, make sure that the AGC reference level is not set too high. If the
volume is too low, try to increase the AGC reference level.
3. If the AGC is disabled and the sound is too weak despite the volume control
being all the way up, try to increase the manual gain.
being all the way up, try to increase the manual gain.
4. In LSB, USB, ISB, DSB and CW modes, manual gain is often preferable to
automatic gain because there is no “carrier” the AGC would act upon and
maintain at a constant level. If AGC is used, then the slow setting is
preferable.
automatic gain because there is no “carrier” the AGC would act upon and
maintain at a constant level. If AGC is used, then the slow setting is
preferable.
Noise Blanker
The Noise Blanker can be used for removal of random high-level noise-spikes
resulting from atmospheric effects and man-made interference.
resulting from atmospheric effects and man-made interference.
There are two types of noise blankers available, one using the Short Time
DDC Averaging method and another one using the ADC Input Threshold
method.
DDC Averaging method and another one using the ADC Input Threshold
method.
The Short Time DDC Averaging method is based on comparing the
instantaneous signal level at the DDC output (demodulator input) to a short-
time exponential average. If the instantaneous level exceeds the short-time
average, these samples will be replaced with zeros.
instantaneous signal level at the DDC output (demodulator input) to a short-
time exponential average. If the instantaneous level exceeds the short-time
average, these samples will be replaced with zeros.
With the ADC Input Threshold method, the blanking effect occurs much
earlier in the signal processing chain: The signal samples arriving from the
ADC are compared to a threshold value, and, if greater, then these samples
are zeroed.
earlier in the signal processing chain: The signal samples arriving from the
ADC are compared to a threshold value, and, if greater, then these samples
are zeroed.