Are we interested in the shape of the DSP filters inside the roofing
filters or are we interested in the performance of the receiver using
recovered audio?
I have done measurements using a broadband noise for the source and
measured spectrum of the recovered audio. Of course as the DSP BW is
changed the recovered audio changes accordingly. The definition at 6 dB
and 60 dB can be attained. I doubt the S meter method is more than an
approximation of values unless all values are related to S units @ 6 dB
per S unit or the value in dBv which can be obtained from the detector
via the Config Menu..
Perhaps Wayne is better qualified to define the performance of the DSP
filter system, usually limited by the number of poles and is done
mathematically. This of course would be somewhat different than the
recovered audio method. Yet, my preference is recovered audio in as
much as that's what we hear.
73
Bob, K4TAX
K3S s/n 10163
On 11/16/2015 6:00 PM, Don Wilhelm wrote:
Charles,
I believe most operators use the RIT control rather than IF Shift to
tune for off frequency stations.
The IF shift is normally used to reduce interference from an
"offending station". That along with the Width control can isolate a
single station with ease and with the 50 Hz minimum DSP bandwidth,
operation in a crowded band segment can actually be a pleasure -
unless an extra strong signal gets past the roofing filter passband
and activates the hardware AGC.
When you get your K3S, give it a try and I think you will find the use
of RIT to be more effective.
Of course, if you ordered the KRX3, you can always go to SPLIT and
eliminate the need for using RIT. Split will cover a much greater
range than RIT.
The KRX3 is not required to operate SPLIT, but if you want to
dynamically listen to your transmit frequency and the desired signal
at the same time, the KRX3 is the only way to do that. Without the
KRX3, you can use the REV button to temporarily listen to your
transmit frequency, but you will not hear both frequencies at the same
time with the REV button.
Yes, I realize this is a bit different than the discussion of filter
shapes and the interaction of the roofing filter with the DSP
filtering. If it is not relevant, then please ignore my comment.
73,
Don W3FPR
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