Re: [Elecraft] K4 and Predistortion
Going back to the original question as for now it seems there is no concrete information available on "predistortion" with the K4. Maybe further information will materialize over the next weeks/months which could be a valid platform for discussions. 73 Roger, DL5RBW -Original Message- From: W2xj [mailto:w...@w2xj.net] Sent: Sunday, May 19, 2019 11:56 AM To: Roger Cc: j...@audiosystemsgroup.com; elecraft@mailman.qth.net Subject: Re: [Elecraft] K4 and Predistortion With EER a class C or D amplifier can deliver an IMD of at least -80 DB but with pre-distortion it could be even better. Sent from my iPad > On May 19, 2019, at 3:38 AM, Roger wrote: > > As pointed out "PreEmphasis/DeEmphasis" and "PreDistortion" are two > different things. So it is important to keep this in mind. To describe > the process a little bit better it the introduction of "DeDistortion" > would help. While DeEmphasis was done at the receiver end DeDistortion > is done at the transmitter end by the amplifier. Just using one part > of Distortion (or > Emphasis) would really not reflect the true signal that is going into > the microphone. As any amplifier stage is adding distortion it is > appropriate to call the procedure done in the SDR (the ones that are > capable of) PreDistortion. The DeDistortion in the amplifier gives you > a much better approximation of a true linear amplification. Just > ADDING Predistortion and not adding or better SUBTRACTING the proper > amount of Dedistortion sure would make and leave the signal distorted. > > 3rd order IMD in the range of -60 dB and with careful design even more > is possible. > > Consider this: the best receiver doesnt help if a lot of average or > below average quality signals are around and splattering into your > "communication channel". The same is true if someone with a radio that > creates a lot of phase noise is next to you - your radio can have a > clean oscillator signal with low phase noise but still the other dirty > signal will go into the equation. > > So after it has been acknowledged that high phase noise oscillators > are a NO GO these days the next consequent step would be to clean up > the transmit signal in terms of intermodulation. > > If someone tuning a motorcycle or a car he better not only tunes the > engine for power but also adapt the brake system the chassis and > everything else affected to handle the more power. > > 73 Roger, DL5RBW > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown > Sent: Sunday, May 19, 2019 2:09 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K4 and Predistortion > >> On 5/18/2019 4:01 PM, Phil Kane wrote: >> Those >> of us with engineering backgrounds knew that what I was referring to >> as "pre-distortion" was the pre-emphasis / de-emphasis curves >> commonly used in FM broadcast audio chains. > > All of which emphasizes the need for using the right words to describe > things. The word "distortion" is most commonly used to describe > non-linearity, not frequency response. And, BTW, that > pre-emphasis/de-emphasis is a Standard, not just "commonly used." You > know the Regs far better than I, but I suspect it's there too. > > As I'm sure you know, it was also common practice to go FAR beyond > that, with multi-band dynamics processing and the tricky stuff that > Bob Orban was doing. The engineering "rule of thumb" was that if you > could see the modulation monitor needle move, you weren't doing > enough.:) > > I did some research on the Orban FM processor, which I published as an > AES Paper in 1986. http://k9yc.com/AESPaper-TDS.pdf > > 73, Jim K9YC > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
With EER a class C or D amplifier can deliver an IMD of at least -80 DB but with pre-distortion it could be even better. Sent from my iPad > On May 19, 2019, at 3:38 AM, Roger wrote: > > As pointed out "PreEmphasis/DeEmphasis" and "PreDistortion" are two > different things. So it is important to keep this in mind. To describe the > process a little bit better it the introduction of "DeDistortion" would > help. While DeEmphasis was done at the receiver end DeDistortion is done at > the transmitter end by the amplifier. Just using one part of Distortion (or > Emphasis) would really not reflect the true signal that is going into the > microphone. As any amplifier stage is adding distortion it is appropriate to > call the procedure done in the SDR (the ones that are capable of) > PreDistortion. The DeDistortion in the amplifier gives you a much better > approximation of a true linear amplification. Just ADDING Predistortion and > not adding or better SUBTRACTING the proper amount of Dedistortion sure > would make and leave the signal distorted. > > 3rd order IMD in the range of -60 dB and with careful design even more is > possible. > > Consider this: the best receiver doesn´t help if a lot of average or below > average quality signals are around and splattering into your "communication > channel". The same is true if someone with a radio that creates a lot of > phase noise is next to you - your radio can have a clean oscillator signal > with low phase noise but still the other dirty signal will go into the > equation. > > So after it has been acknowledged that high phase noise oscillators are a NO > GO these days the next consequent step would be to clean up the transmit > signal in terms of intermodulation. > > If someone tuning a motorcycle or a car he better not only tunes the engine > for power but also adapt the brake system the chassis and everything else > affected to handle the more power. > > 73 Roger, DL5RBW > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown > Sent: Sunday, May 19, 2019 2:09 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K4 and Predistortion > >> On 5/18/2019 4:01 PM, Phil Kane wrote: >> Those >> of us with engineering backgrounds knew that what I was referring to >> as "pre-distortion" was the pre-emphasis / de-emphasis curves commonly >> used in FM broadcast audio chains. > > All of which emphasizes the need for using the right words to describe > things. The word "distortion" is most commonly used to describe > non-linearity, not frequency response. And, BTW, that > pre-emphasis/de-emphasis is a Standard, not just "commonly used." You know > the Regs far better than I, but I suspect it's there too. > > As I'm sure you know, it was also common practice to go FAR beyond that, > with multi-band dynamics processing and the tricky stuff that Bob Orban was > doing. The engineering "rule of thumb" was that if you could see the > modulation monitor needle move, you weren't doing enough.:) > > I did some research on the Orban FM processor, which I published as an AES > Paper in 1986. http://k9yc.com/AESPaper-TDS.pdf > > 73, Jim K9YC > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
As pointed out "PreEmphasis/DeEmphasis" and "PreDistortion" are two different things. So it is important to keep this in mind. To describe the process a little bit better it the introduction of "DeDistortion" would help. While DeEmphasis was done at the receiver end DeDistortion is done at the transmitter end by the amplifier. Just using one part of Distortion (or Emphasis) would really not reflect the true signal that is going into the microphone. As any amplifier stage is adding distortion it is appropriate to call the procedure done in the SDR (the ones that are capable of) PreDistortion. The DeDistortion in the amplifier gives you a much better approximation of a true linear amplification. Just ADDING Predistortion and not adding or better SUBTRACTING the proper amount of Dedistortion sure would make and leave the signal distorted. 3rd order IMD in the range of -60 dB and with careful design even more is possible. Consider this: the best receiver doesn´t help if a lot of average or below average quality signals are around and splattering into your "communication channel". The same is true if someone with a radio that creates a lot of phase noise is next to you - your radio can have a clean oscillator signal with low phase noise but still the other dirty signal will go into the equation. So after it has been acknowledged that high phase noise oscillators are a NO GO these days the next consequent step would be to clean up the transmit signal in terms of intermodulation. If someone tuning a motorcycle or a car he better not only tunes the engine for power but also adapt the brake system the chassis and everything else affected to handle the more power. 73 Roger, DL5RBW -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown Sent: Sunday, May 19, 2019 2:09 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K4 and Predistortion On 5/18/2019 4:01 PM, Phil Kane wrote: > Those > of us with engineering backgrounds knew that what I was referring to > as "pre-distortion" was the pre-emphasis / de-emphasis curves commonly > used in FM broadcast audio chains. All of which emphasizes the need for using the right words to describe things. The word "distortion" is most commonly used to describe non-linearity, not frequency response. And, BTW, that pre-emphasis/de-emphasis is a Standard, not just "commonly used." You know the Regs far better than I, but I suspect it's there too. As I'm sure you know, it was also common practice to go FAR beyond that, with multi-band dynamics processing and the tricky stuff that Bob Orban was doing. The engineering "rule of thumb" was that if you could see the modulation monitor needle move, you weren't doing enough.:) I did some research on the Orban FM processor, which I published as an AES Paper in 1986. http://k9yc.com/AESPaper-TDS.pdf 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
On 5/18/2019 4:01 PM, Phil Kane wrote: Those of us with engineering backgrounds knew that what I was referring to as "pre-distortion" was the pre-emphasis / de-emphasis curves commonly used in FM broadcast audio chains. All of which emphasizes the need for using the right words to describe things. The word "distortion" is most commonly used to describe non-linearity, not frequency response. And, BTW, that pre-emphasis/de-emphasis is a Standard, not just "commonly used." You know the Regs far better than I, but I suspect it's there too. As I'm sure you know, it was also common practice to go FAR beyond that, with multi-band dynamics processing and the tricky stuff that Bob Orban was doing. The engineering "rule of thumb" was that if you could see the modulation monitor needle move, you weren't doing enough.:) I did some research on the Orban FM processor, which I published as an AES Paper in 1986. http://k9yc.com/AESPaper-TDS.pdf 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
On 5/18/2019 9:42 AM, Bob McGraw K4TAX wrote: > Tongue and cheek, .from what I hear on the bands, pre-distortion > starts with mostly that which comes out of the operators mouth. > Electronics won't improve this artifact. For sure! Same with current music. No extra charge for the distorted sound. Reminds me of a case some 45 years ago involving broadcast signal quality where I was testifying as the FCC's engineering expert. Those of us with engineering backgrounds knew that what I was referring to as "pre-distortion" was the pre-emphasis / de-emphasis curves commonly used in FM broadcast audio chains. The non-engineer lawyers jumped up and down "what, they are intentionally distorting the station's sound?" Took a while to educate them from the witness box. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
Hi Roger, You wrote "With the radios receiverwise reaching the physical limits it now is time to pull up the transmitter side to the state of the art as well. Regarding transmit IMD we are still in the 70s or 80s and sometimes even worse than that therefore no progress has been made the last 40 to 50 years!" I couldn't agree with you more ! BTW, there is now a new K4 group on groups.io, which is promising since the K3 group is now inundated with K4 stuff. AB2TC - Knut Roger-3 wrote > As there is a lot of buzz going around with the announced K4 and I have > seen > 1 or 2 messages on this reflector that referred to "Predistortion" I > wonder > if there is any further detail on that. I probably fall out of the regular > scheme as I couldn´t care less about the ability for remote control and > another 10 USB ports rather than predistortion. FLEX is using the customer > request for more remote control possibilities and more USB ports to hold > their 5 or 6 years ago announced predistortion on standby - at least that > is > what they say. With the radios receiverwise reaching the physical limits > it > now is time to pull up the transmitter side to the state of the art as > well. > Regarding transmit IMD we are still in the 70s or 80s and sometimes even > worse than that therefore no progress has been made the last 40 to 50 > years! > > So is there any deadline (vague or not) when predistortion will be > implemented? > > 73s Roger, DL5RBW > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto: > Elecraft@.qth > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
There is an input on the real panel for a “sample” from an RF amp. No indication that I’ve seen yet on the purpose of this input. I suspect it may be a while before all is revealed .. :-) Grant NQ5T K3 #2091 KX3 #8342 > On May 18, 2019, at 12:42 PM, Bob McGraw K4TAX wrote: > > Tongue and cheek, .from what I hear on the bands, pre-distortion > starts with mostly that which comes out of the operators mouth. Electronics > won't improve this artifact. > > 73 > > Bob, K4TAX > > > On 5/18/2019 11:35 AM, Roger wrote: >> As there is a lot of buzz going around with the announced K4 and I have seen >> 1 or 2 messages on this reflector that referred to "Predistortion" I wonder >> if there is any further detail on that. I probably fall out of the regular >> scheme as I couldn´t care less about the ability for remote control and >> another 10 USB ports rather than predistortion. FLEX is using the customer >> request for more remote control possibilities and more USB ports to hold >> their 5 or 6 years ago announced predistortion on standby - at least that is >> what they say. With the radios receiverwise reaching the physical limits it >> now is time to pull up the transmitter side to the state of the art as well. >> Regarding transmit IMD we are still in the 70s or 80s and sometimes even >> worse than that therefore no progress has been made the last 40 to 50 years! >> >> So is there any deadline (vague or not) when predistortion will be >> implemented? >> >> 73s Roger, DL5RBW >> __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K4 and Predistortion
Tongue and cheek, .from what I hear on the bands, pre-distortion starts with mostly that which comes out of the operators mouth. Electronics won't improve this artifact. 73 Bob, K4TAX On 5/18/2019 11:35 AM, Roger wrote: As there is a lot of buzz going around with the announced K4 and I have seen 1 or 2 messages on this reflector that referred to "Predistortion" I wonder if there is any further detail on that. I probably fall out of the regular scheme as I couldn´t care less about the ability for remote control and another 10 USB ports rather than predistortion. FLEX is using the customer request for more remote control possibilities and more USB ports to hold their 5 or 6 years ago announced predistortion on standby - at least that is what they say. With the radios receiverwise reaching the physical limits it now is time to pull up the transmitter side to the state of the art as well. Regarding transmit IMD we are still in the 70s or 80s and sometimes even worse than that therefore no progress has been made the last 40 to 50 years! So is there any deadline (vague or not) when predistortion will be implemented? 73s Roger, DL5RBW __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] K4 and Predistortion
As there is a lot of buzz going around with the announced K4 and I have seen 1 or 2 messages on this reflector that referred to "Predistortion" I wonder if there is any further detail on that. I probably fall out of the regular scheme as I couldn´t care less about the ability for remote control and another 10 USB ports rather than predistortion. FLEX is using the customer request for more remote control possibilities and more USB ports to hold their 5 or 6 years ago announced predistortion on standby - at least that is what they say. With the radios receiverwise reaching the physical limits it now is time to pull up the transmitter side to the state of the art as well. Regarding transmit IMD we are still in the 70s or 80s and sometimes even worse than that therefore no progress has been made the last 40 to 50 years! So is there any deadline (vague or not) when predistortion will be implemented? 73s Roger, DL5RBW __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
