I have read a few statements here concerning NR and filter tap settings and
audio distortion and other perceived effects of the DSP filter system on the
ORION II. I've read the manual too...
The filter tap setting is to adjust the skirt angle or selectivity of a
given filter setting. A setting of 32 would be a long sloping skirt and 199
would be a steep (highly selective) skirt. I have not found the relevant
dB/bandwidth comparison to use in this adjustment, so perhaps this filter
tap setting is interdependent on other settings, such as RF gain and AGC???
The NR function is supposed to determine the signal level in the noise and
then adjust the DSP filter to accentuate the signal through this noise.
Once the determination is made by the NR logic, then adjusting the level
from 1 to 9 has no further effect on the currently "captured" or determined
signal and the NR setting. The 1 to 9 setting only determines the time it
takes for the NR logic to make its sampling of the signal and resolve it or
conclude what it is and adjust. So... What is the interaction between this
NR circuit, AGC, RF Gain, Filter Tap setting, and ATTN?
I have worked with it some and have found that it is very effective on CW
signals near, but above the noise floor. It will bring them out and make
reception easier. On SSB signals I notice some distortion as though the AGC
were pumping or clipping on the strong signals, but quite effective on the
very weak ones. I have yet to hear a NR system that works any better, or as
well for that matter, but all of them seem to introduce some distortion to a
SSB phone signal. My comparison NR systems are in the Motorola MICOM 2es
DSP NR, not good, Icom PRO II NR system, good, and the ORION II NR system,
perceived to be substantially better than the previous two. The noise does
not necessarily reduce, but I notice the Signal improves audibly as compared
to the noise or S/N ratio improves. On the Icom 756 PRO II the noise is
noticeably reduced and so is the signal, but in the overall effect the
signal is usually more readable, in the Micom 2es the noise is not reduced
but to some degree the SSB audio is improved although not enough to make
this system useful in my environment. These comparisons may seem
irrelevant, but these different radio NR systems help me to compare and draw
a relevant conclusion that the ORION II NR system is superior in effect to
other high quality radios.
So would someone who really knows, tell me how the NR system in the ORION II
interacts with the DSP settings already in effect when it is engaged and if
there are optimal DSP settings to be made prior to engaging the NR system so
that it is able to function more effectively? Or if the NR system is
totally independent of all other DSP settings and will auto adjust
irregardless.
Ron
KA7U
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