Of course, god saves us from people leaving the trodden road. Safer to stay with the 30+ years old stuff
jd
It is still: The three phases of an idea.
1. It won't work. Too much distortion, gain instability, etc
2. It works, but it is not important. Tested it at X100, didn't bother to follow up.
3. We invented it. I would have done it even better and quieter, if I really wanted to.
How about that everyone?
1. It won't work. Too much distortion, gain instability, etc
2. It works, but it is not important. Tested it at X100, didn't bother to follow up.
3. We invented it. I would have done it even better and quieter, if I really wanted to.
How about that everyone?
I see a blip. So what? I certainly can't give a source for every blip on the screen. That is your responsibility because you are the one asserting that it distinguishes TIM from PIM. I don't know that it does, and I don't think you do either.
Cheers,
Bob
Scott, to make myself clear in case this was referred to my earlier response, I wasn't referring to you but to 'management' in general. I know you like to explore the untrodden road. Wish I had such a wide brain as you have...
cheers,
jd
Like, "$1 for knocking the nail, and $999,999 for knowing which one to knock".
John, you are name-dropping again
Yes I remember Bessel functions and the accompanying pain. You did not read my earlier post very well. I stated that any PIM distortion was akin to narrow-band fm. Go look up narrow band fm. The Bessel functions devolve to linear functions at low deviation.
Bob
Yes, but I'm afraid it would be useless. Nobody ever won an argument against you, and unfortunately not because you are always right, but because you won't ever admit you are wrong.
Anyway, there's nothing to prove or further investigate in your statement. Each PM or FM signal expands as an infinite sum of products between the Bessel functions of i-th order and the i-th order sidebands. Also obviously, as long as the PM or FM modulation is "small", high order products can always be safely neglected, so only low order Bessel functions matter.
So essentially your statement is empty of any meaning, beyond basic engineering knowledge. You failed again in adding any argument to your extraordinary claims regarding PIM.
There are any number of easily obtained references. http://www.st-andrews.ac.uk/~jcgl/Scots_Guide/RadCom/part12/page1.html
Getting non-harmonicly related output remains an extraordinary claim.
Hi
Just a link to an online book:
MATHEMATICS OF THE
DISCRETE FOURIER TRANSFORM (DFT)
WITH AUDIO APPLICATIONS
SECOND EDITION
Cheers
http://www.dsprelated.com/dspbooks/mdft/
Just a link to an online book:
MATHEMATICS OF THE
DISCRETE FOURIER TRANSFORM (DFT)
WITH AUDIO APPLICATIONS
SECOND EDITION
Cheers
http://www.dsprelated.com/dspbooks/mdft/
Attachments
Everyone, I am not the discoverer of the PIM interspersed with TIM.
It was Mitch Cotter, who first pointed it out to me, recently, and he told me that he showed Matti Otala the same thing (perhaps on a different graph), more than 30 years ago. This is apparently what got Matti Otala on the path of including PIM into the group as an important distortion source.
Mitch Cotter has a strong FM background and is associated with the design of the Marantz 10B tuner along with Dick Sequerra.
Now, sorry about 'name dropping' but these are the people who I have had 1 hour or more conversations about this subject in the last 24 hours. Sorry, I didn't speak to Saul Marantz, as he is deceased and he couldn't help much anyway, since he wasn't really technical.
These are my peers, and they have been for the last 25 years.
Bessel was a little before my time, and I would have taken Heaviside's position on just about everything, in any case. Fourier, what a guy!
It was Mitch Cotter, who first pointed it out to me, recently, and he told me that he showed Matti Otala the same thing (perhaps on a different graph), more than 30 years ago. This is apparently what got Matti Otala on the path of including PIM into the group as an important distortion source.
Mitch Cotter has a strong FM background and is associated with the design of the Marantz 10B tuner along with Dick Sequerra.
Now, sorry about 'name dropping' but these are the people who I have had 1 hour or more conversations about this subject in the last 24 hours. Sorry, I didn't speak to Saul Marantz, as he is deceased and he couldn't help much anyway, since he wasn't really technical.
These are my peers, and they have been for the last 25 years.
Bessel was a little before my time, and I would have taken Heaviside's position on just about everything, in any case. Fourier, what a guy!
Thank Stinius, anything from CCRMA is interesting to me. I was just reading an article in the latest IEEE 'Spectrum' Sept. 2009, p. 24 last night about a guy from CCRMA who does interesting things there. Perhaps this will give me a bigger clue as to the subtle differences between DFT and FFT. Any real tradeoffs in info?
John, did these people give you hard factual data and arguments for their position? If so, why don't you just give them here and teach us all something? Or did you just believe them on their blue eyes and expect everyone else to do the same?
jd
They convinced me, already. But then I am more willing to learn new things, and accept that some people actually know more than me about it. I do have a call into Mitch Cotter. He is tied up on his project, but I did leave a message asking for further details, just 1/2 hour ago. It may be until tomorrow, before I hear from him. I have tried over the last 18 hours, already.
Personally, I don't need to convince anyone here about anything. It is your gain or loss to follow up. It is now obvious to me, but it is because I participated in presenting the original graph, and did dozens of separate measurements, myself, in Matti's lab, getting the same graphs. I KNOW the test procedure, and its correctness.
What Mitch Cotter contributed, was NOTING the FM distortion as it would appear on the same graph. He showed Matti, Matti verified it, himself, (didn't tell me), thanked Mitch, then wrote his first paper on PIM, ALL math, no measurements. I just met up with Mitch a few months ago, and we talk almost every day. Does this help?
Personally, I don't need to convince anyone here about anything. It is your gain or loss to follow up. It is now obvious to me, but it is because I participated in presenting the original graph, and did dozens of separate measurements, myself, in Matti's lab, getting the same graphs. I KNOW the test procedure, and its correctness.
What Mitch Cotter contributed, was NOTING the FM distortion as it would appear on the same graph. He showed Matti, Matti verified it, himself, (didn't tell me), thanked Mitch, then wrote his first paper on PIM, ALL math, no measurements. I just met up with Mitch a few months ago, and we talk almost every day. Does this help?
I would like to see the math for the non-harmonically related frequencies or how three orders of magnitude more PM in a speaker than an average amplifier does not matter.
This would be good technical stuff that would interest everyone I would think. I would hope "we just hear this stuff" is not the fall back position.
This would be good technical stuff that would interest everyone I would think. I would hope "we just hear this stuff" is not the fall back position.
John,
The question remains, how do you or anyone else know that the blip is due to PIM or something else?
You assert that this blip must be PIM because is is not related in an N/M way to the frequencies in the test. Ask one of your friends to explain why this is the case.
It is also very unclear how a non-N/M product can be created by this test.
Just saying it is so does not make it so. Just having your colleagues or some famous person say it is so and then have it repeated second-hand by you does not make it so. You asserted that Barrie Gilbert's paper proved your point on PIM. That is not so, even though Barrie did not make any mistakes. I frankly think that you are very much in the habit of putting your own spin on what others say.
Cheers,
Bob
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