Hi Ken,
The short answer is "both".
The 1st I.F. noise blanker module is ahead of the roofing filters, so
it can blank wideband pulse noise. It has a wide AGC range and various
threshold and blanking width settings.
There's also a DSP noise blanker *after* the roofing filters. This
blanker has the advantage of not being modulated by signals outside the
roofing filter bandwidth. Of course you can't use it in all cases,
because the roofing filter stretches the pulses and thus requires
longer blanking times. But I have some noise on 160 m that the DSP
blanker suppresses by some 40 dB, making otherwise completely inaudible
signals stand out clearly. We're also experimenting with reconstructive
blanking algorithms to make the DSP blanker even more effective.
The noise blanker LEVEL switch displays the parameters for both the
hardware blanker and the DSP blanker on the VFO A and VFO B displays.
You can then adjust either or both to see which is most effective on
noise. The settings are stored on a per-band basis.
73,
Wayne
N6KR
On Jun 12, 2007, at 4:50 AM, Kenneth A. Christiansen wrote:
Is the noise blanker on the K3 ahead of the roofing filter or behind
the roofing filter....?
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