[Elecraft] AGC Settings and DSP 1.87

[W7TEA]

Lyle, can you describe what the Threshold value might be at a particular 
numerical setting? For example, is AGC action initiated at about 5 uv
with a setting of "3" and a setting of "2" might be at 1 uv. 

I'm still trying to understand how this works.  It seems the Orion
threshold setting worked in the opposite way--that is, lowering the 
threshold raised the signal level.  Or maybe my memory is faulty.

thanks,  Gary W7TEA





Lyle Johnson wrote:
> 
> DSP firmware 1.87 corrects two AGC problems occasionally resulting in 
> complaints of unexpectedly loud signals in an operator's headphones.
> 
> The first lowers the AGC threshold.  It was inadvertently raised 
> sometime after release 1.47.  It is now back to its original range.
> 
> The second corrects a problem in the AGC slope.  As signals grew 
> stronger, the AGC was not properly restricting their range, particularly 
> for signals from about S9 to the activation of hardware AGC (about S9+5 
> or 10 in the earliest K3s; about S9+20 in later K3s and those with the 
> HAGC mod).
> 
> The new code sets the slope of the AGC as "linear in dB."  This means 
> that if you have it set for, say, 1 dB of output change for 10 dB of 
> signal change, then an input signal change of 40 dB will result in about 
> a 4 dB change in the audio level.
> 
> The slope now ranges from essentially flat output (CONFIG:AGC SLP 15) to 
> about 3.75 dB audio rise per 10 dB signal rise (CONFIG:AGC SLP 0).  Each 
> step is about 0.25 dB audio change per 10 dB of input signal change.
> 
> You probably won't need to alter any AGC settings in your K3, but you 
> may want to experiment with different values of CONFIG:AGC THR and 
> CONFIG:AGC SLP.  Remember, there is no "correct" setting; the K3 is 
> designed to be tailored to your preferences.
> 
> Enjoy!
> 
> 73,
> 
> Lyle KK7P
> 
> 

-- 
View this message in context: http://n2.nabble.com/K3-Beta-Firmware-Release----MCU-Revision-2.19-tp577543p579742.html
Sent from the Elecraft mailing list archive at Nabble.com.