[Elecraft] Sherwood on K3 AGC transients

[wayne burdick]

Ian wrote:

> Did Rob comment on pops and transients generated in the AGC and DSP?
>
> That was  the subject of his presentation at Dayton 2007, where he gave
> many examples to show that "New IF DSP designs [can] seriously
> exaggerate transient noise on weak signals... Some DSP radios make QRN
> much worse."
>
> He also said, "I can’t wait to listen to the K3 to see if they got it
> right." And...?


According to Rob, we did "get it right." He told us that his test pulse 
resulted in essentially no upward S-meter movement or AGC activation. 
(Rob mentioned that he'd be adding a column to his table to indicate 
which rigs pass this test and which don't.)

To achieve this, we created a DSP algorithm that can tell the 
difference between transient pulses and useful signals, over a fairly 
wide amplitude and duration range. Obviously you can't remove all such 
transients -- some have complex waveforms and long durations and are 
better dealt with using a combination of noise blanking and noise 
reduction. But it works very well on most "shot" events.

73,
Wayne
N6KR


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