[Elecraft] Sherwood on K3 AGC transients

[Ian White GM3SEK]

wayne burdick wrote:
>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

Excellent - thank you, Wayne and Rob.


-- 

73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek