K3 Compression compared to CESSB
Locked
K3 Compression compared to CESSB
 
|
Given the recent article in QST explaining CESSB I looked for some detail
about the compression algorithm of the K3 but found nothing explaining how it works.It is the most effective processing I have ever used and appears to double the transmit power. So perhaps it is a version of CESSB or efficient enough to be left alone as is. Perhaps I missed some discussion on this.Is there a published explanation of the compression algorithm? (not in Fred's book, I looked and checked with him) Bob K7VO ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]
Robert Sands
K7VO Olympia, WA |
Re: K3 Compression compared to CESSB
|
|
I have studied and measured both the Compression algorithm and, as a
separate project, the ALC operation using my K3S. It is clear the ALC system is very different as implemented in the K3S from other radios in as much as there is some gain ranging which occurs below the 5th bar of ALC indication. After and above the 5th bar the system goes into a gain reduction scheme, somewhat typical of other ALC systems. One key to ALC systems which make them very different is the attack time the release time and the compression/limiting ratio, meaning input signal change vs. output signal change. All in all, the K3S system is very clever and much like audio processing as used in commercial broadcast applications. Perhaps this accounts for the excellent results. This is clear for those that work digital modes and are instructed to adjust the input level to the point the 5th bar is flickering when using the K3S. Clearly, until one understands this, most revert to instructions found with digital programs, digital interfaces and other radios which clearly say "adjust to the point below ALC action". In the case of the K3s, there is really no ALC action below the 5th bar. In fact the value as show on the ALC scale below the 5th bar is more of a VU type indication with some degree of level expansion. As to CESSB, the articles in QEX and QST February are very interesting and enlightening. It is interesting note that the CESSB methodology increases the average power by a factor of some 2.5. Of course the major advantage is not only increased average power output but greatly reduced distortion as a result of the method employed. It will be very interesting to see how all this plays out in regard to implementation in future radio designs. 73 Bob, K4TAX On 1/22/2016 9:47 AM, Robert Sands wrote: > Given the recent article in QST explaining CESSB I looked for some detail > about the compression algorithm of the K3 but found nothing explaining how > it works.It is the most effective processing I have ever used and appears > to double the transmit power. So perhaps it is a version of CESSB or > efficient enough to be left alone as is. Perhaps I missed some discussion > on this.Is there a published explanation of the compression algorithm? (not > in Fred's book, I looked and checked with him) > Bob > K7VO > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
In reply to this post by Robert Sands
The method is proprietary.
I'm quite assured Wayne is reading up on CESSB. But I could hardly blame him for not wanting to engage in an open discussion on a proprietary process that is embedded in a proprietary SDR radio operating system. It's called protecting one's commercial advantage. There are very high tech and inventive reasons why Elecraft is so far ahead at its relative low cost, contrary opines from boo birds and pathological Elecraft detractors notwithstanding. And we think Wayne is obliged to discuss these things in public because ??? I'm just as curious as the next guy. He might talk about it here but he certainly is not obligated. 73, Guy K2AV On Friday, January 22, 2016, Robert Sands <[hidden email]> wrote: > Given the recent article in QST explaining CESSB I looked for some detail > about the compression algorithm of the K3 but found nothing explaining how > it works.It is the most effective processing I have ever used and appears > to double the transmit power. So perhaps it is a version of CESSB or > efficient enough to be left alone as is. Perhaps I missed some discussion > on this.Is there a published explanation of the compression algorithm? (not > in Fred's book, I looked and checked with him) > Bob > K7VO > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] <javascript:;> > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] <javascript:;> > -- Sent via Gmail Mobile on my iPhone ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
On Fri,1/22/2016 9:27 AM, Guy Olinger K2AV wrote:
> The method is proprietary. > > I'm quite assured Wayne is reading up on CESSB. But I could hardly blame > him for not wanting to engage in an open discussion on a proprietary > process that is embedded in a proprietary SDR radio operating system. It's > called protecting one's commercial advantage. Yep. And I found Bob McGraw's analysis quite perceptive. Having retired from a career in broadcasting, he "gets" audio processing. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
In reply to this post by Bob McGraw - K4TAX
Slight correction: not a factor of 2.5, but 2.5 dB, which is a factor of about 1.8.
Al W6LX >>> It is interesting note that the CESSB methodology >>>increases the average power by a factor of some 2.5. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
Re: QST February 2015, page 30, Figure 1 "Conventional SSB (blue)
compared to CESSB (red) have the same PEP, but the average power of CESSB is 2.28 times greater." I amend my statement from 2.5 to 2.28. 73 Bob, K4TAX On 1/22/2016 1:47 PM, Al Lorona wrote: > Slight correction: not a factor of 2.5, but 2.5 dB, which is a factor of about 1.8. > > > Al W6LX > > > >>>> It is interesting note that the CESSB methodology >>>> increases the average power by a factor of some 2.5. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
OOPs that should be 2016 on the QST date. Sorry.
73 Bob, K4TAX On 1/22/2016 1:57 PM, Bob McGraw K4TAX wrote: > Re: QST February 2015, page 30, Figure 1 "Conventional SSB (blue) > compared to CESSB (red) have the same PEP, but the average power of > CESSB is 2.28 times greater." > > I amend my statement from 2.5 to 2.28. > > 73 > Bob, K4TAX > > > > > > On 1/22/2016 1:47 PM, Al Lorona wrote: >> Slight correction: not a factor of 2.5, but 2.5 dB, which is a factor >> of about 1.8. >> >> >> Al W6LX >> >> >> >>>>> It is interesting note that the CESSB methodology >>>>> increases the average power by a factor of some 2.5. > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
In reply to this post by Bob McGraw - K4TAX
Okay, I see what you're looking at... I believe that's a plot of the output of a simulation, whereas in practice he's seeing about 2.5 dB [re: the original technical article in QEX Nov/Dec 2014].
Al W6LX ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
Agreed.
73 Bob, K4TAX On 1/22/2016 2:13 PM, Al Lorona wrote: > Okay, I see what you're looking at... I believe that's a plot of the > output of a simulation, whereas in practice he's seeing about 2.5 dB > [re: the original technical article in QEX Nov/Dec 2014]. > > Al W6LX > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
In reply to this post by alorona
Afternoon all,
Today, a new mystery has come into the shack of W1IE. Whenever I click on a frequency displayed in a cluster like VE7CC for 20 meters, the K3 display shows the frequency plus 100hz high ie. I select 14020. Get on the display 14020.1. It does not do it on the other bands. Any thoughts anybody? \Best regards, Jerry, W1IE ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: 20M Frequency kinda of messed up
|
|
Check your XIT button.
Rick nhc On 1/22/2016 12:38 PM, Jerry wrote: > Afternoon all, > > Today, a new mystery has come into the shack of W1IE. Whenever I click on a > frequency displayed in a cluster like VE7CC for 20 meters, the K3 display > shows the frequency plus 100hz high ie. I select 14020. Get on the display > 14020.1. > > It does not do it on the other bands. Any thoughts anybody? > > \Best regards, > > Jerry, W1IE > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
In reply to this post by Robert Sands
I wouldn't expect there to be.
Firmware is the holy grail of SDR and is really the only thing that differentiates one rig from another. As such it should be protected and proprietary. On 1/22/2016 9:47 AM, Robert Sands wrote: > Is there a published explanation of the compression algorithm? (not > in Fred's book, I looked and checked with him) > Bob > K7VO -- R. Kevin Stover AC0H ARRL FISTS #11993 SKCC #215 NAQCC #3441 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Compression compared to CESSB
|
|
Yes I agree. And I find the compression algorithm and ALC tables are
really difficult to figure out from the outside world too. 73 Bob, K4TAX On 1/22/2016 7:35 PM, Kevin Stover wrote: > I wouldn't expect there to be. > Firmware is the holy grail of SDR and is really the only thing that > differentiates one rig from another. > As such it should be protected and proprietary. > > On 1/22/2016 9:47 AM, Robert Sands wrote: >> Is there a published explanation of the compression algorithm? (not >> in Fred's book, I looked and checked with him) >> Bob >> K7VO > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |