[Elecraft] W2IHY 8 band equalizer and EQ Plus

Thu Apr 29 01:07:11 EDT 2010

Lu,

I don't know if it is my email client or your responses, but I cannot 
make much sense of your in-line questions/comments.
Please ask your questions in plain English in a single coherent 
statement.  combing through a bunch of things trunchated by blue bars on 
my email client is totally confusing.

Sorry if I am being an old 'fuddy-duddy', but I simply cannot readily 
see which are your questions and which are the things you are referring 
to.  Concise questions please.

73,
Don W3FPR

Luis V. Romero wrote:
> Some quick questions (yeah, I know I said I would stop, but I cant help it,
> I want to understand!)
>
>   
>> "...a Pre-DSP two band audio leveler/AGC and handles for Attack, Decay and
>>     
> Ratio on the RF Clipper."
>   
>> That is, prior to Digital Signal Processing, or before analog is converted
>>     
> to digital.
>
> Where exactly does the input to the TX DSP section (OK, IF section) hit an
> ADC?  Where do we move from the Analog domain to the Digital domain?  Where
> is the "quantizer" for the mic input?  Would make sense if it was before the
> Clipper, right? 
>
>   
>> In your headroom explanation, is there a common instance of microphone ADC
>>     
> saturation that needs to be reported?  >That's a pretty seventh-grade
> mistake on Wayne's part if it's true.  (Yeah, I know, the first Hubble
> lenses, and >the unit snafu on the Mars landers, also very seventh-grade.)
>
> I don't believe that's it at all.  I can punch holes into the audio if I
> speak softly then speak loudly.  Sounds to me like there is some kind of
> compression happening (that is why I first incorrectly assumed that this
> thing used a compressor not a kind of IF/RF Clipper).  What happens is that
> the radio grabs the loud syllable and holds off from releasing the gain
> reduction for a bit, then recovers.  If you hit it with something loud, then
> something soft, you hear the hole.  The decay of whatever is grabbing the
> peak is slower than the attack.  There is no overshoot that I can discern
> with my ears, as the firmware must be dropping audio into a buffer and
> setting the response in kind.  I once heard people complain about delay in
> the monitor, I do hear a very slight one.  So there must be a look ahead
> buffer that computes the response to the peak.  All I'm saying is that it
> would be nice to have a handle on at least the decay, so it can more match
> the attack.  Probably cant do that as it would create more delay in the
> monitor.  It's a fine line.
>
>   
> "What I was suggesting is an AGC funtion before the RF Clipping section
> touches the audio waveform.  Something to smooth out the dynamic range of
> the audio input so that the DSP processing engine would not have to work so
> hard dealing with peaks and valleys and can be "let loose" some."
>
> Elecraft is already accomplishing envelope leveling and shaping with digital
> functions that don't appear to >resemble the sledge and wedge of RF clipping
> and AF variable band amplifiers. SOME folks get excellent results using the
> K3's leveling and shaping processes for TX audio.  I would hate to bring up
> RTFM on setting up K3 mic gain and compression, but the manual procedure
> does seem to work.
>   
>
> I would like to get a better understanding of the process that is used here.
> I do use the manual settings, It does work well, and does sound good, but I
> would like to understand what is happening under the hood better so I can
> better adapt to what this rig likes to hear, which, to me, is consistent
> levels.  My old admittedly analog rig was less picky and had much more room
> to play with (when I let it).  Hopefully that is not Elecraft Secret Sauce.
>
>   
> AND, since there is NO analog audio band circuitry in there anywhere, BUT
> there ARE banded TX and RX equalizer functions being done in the number
> soup, whose gains are being set by NUMBERS we enter in the menu, what makes
> us think he hasn't already done something proprietary about "banded gain"
> which he is developing further and is not about to reveal so the competition
> can't copy it for free?
>   
>
> This is probably the Secret Sauce I'm talking about.  Are you implying
> 8-band digital split band processing?
>
>   
> You should have seen the look I got from the oldest one when I asked him if
> the audio actually went through all the slide pots on one of those big
> digital mixers he was running, the look that says "Please don't talk like
> that when my friends are around."
>   
>
> That's pretty funny.  On my side, the video side, I was explaining to a
> pretty hot non linear editor how we did non-b-roll match frame editing with
> timecode on helical composite VTR's and the importance of the color frame
> sequence across 4 fields (360 degrees of subcarrier and matching subcarrier
> to horizontal sync) so that the picture wouldn't jump at the match frame in
> NTSC.  Couldn't understand the process!  Couldn't even begin to understand
> true A/B rolls either.  So I know what you mean.
>
>   
>>    
>>     
> there is no K3 RX AF analog circuit controlled by AF gain.  There is no K3
> RX RF analog circuit controlled by RF gain. The AF and RF pot settings are
> immediately turned into "advice" numbers and passed along to the MCU.
>   
>
> Advice in the way of a VCA setting?  Wonder what the granularity is.  It is
> an analog pot, so logically we read a voltage and digitize it, then report
> it to the MCU.
>
> Thanks for pointing me in the right direction, Guy.  Now I know the probable
> true reason for the annoying "cant talk to the RX controls while in TX"
> behavior.  A hybrid Parallel/Serial signal bus.  
>
> I'm afraid I pushed paper from the left side to the right side of a desk for
> way too long.  
>
> -lu- 
>
>
>
>
> No virus found in this outgoing message
> Checked by PC Tools AntiVirus (6.1.0.25 - 6.14830).
> http://www.pctools.com/free-antivirus/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>   