Its fine (CD) for most people who just want to hear some sounds similar to music. MP3 also. Here in this forum is more about accuracy and realism. At least to a few of us.
THx-RNMarsh
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No, not picking anything. Edit: 20/4 is shorthand for sin(20khz)*cos(4khz)
You stated it was suppressed carrier modulation. Why is there any 20k at all in the 20/4 FFT? Doesn't suppressed carrier mean no carrier?
Repeat the FFT with two lobes, as the second lobe has flipped 20 kHz carrier. See if the carrier is still so prominent.
When an FFT is run on a 20khz carrier modulated by cos(4K), there should be NO 20khz in the spectra. It should be all 16 and 24. The fact that 20 is there means something is incorrect..so it is important to know what..that question should be a meatball hanging there in space.
So I repeat...
Place a 20/4 through a filter Fs at 21 kHz to remove the 24khz sideband.
Display the time based output.
Compare it to an 18/2 unfiltered signal, again, time based output.
Jn
And don't forget, Hans is modulating raised sine, you and I are speaking cos. Getting rid of the carrier helps clarify the issue..raised sine doesn't flip the carrier.
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This kind of anecdotal stuff has been rehashed hundreds of times in the Blowtorch thread and does not add anything to the current discussion.
I understand very well the people and how you were treated by truely bright/brilliant people. They invited me to work with researchers in the Ivory Tower of EE research contributing and helping write papers. If you demonstrated you can do it, they invite the help and creativity with open arms.
I understand Einstein also could not do the math as well as he needed. His ideas and concepts are still being investigated by others'.
In 25 years of being with and working with these minds, only one had an ego issue... he had a PHD and I had been asked to contact him to work on some seismic structure issues for us. When he wasnt performing as we expected.... I was asked whats going on..... he later said he didnt know who i was etc. He didnt think I had enough status to tell him what we needed him to do. I had not talked to him with respect and reverence so he wasnt going to cooperate. I had an opinion about that to my group leader. The PHd later apologized and got right on it.
But the ego's here are really,really over the top.
THx-RNMarsh
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This paper is a bit light and I am not too impressed. Lots of references and assumptions with little evidence they have been vetted properly.
Unless the 16 and 20 components are exactly equal it is not simply 18/2. Please look at the trig identities again they don't have any carrier in the output.
At first blush, that appears to be the takeaway here.
However, I still believe it may be that the format of discussion on a forum is not conducive to a really good collaborative effort. It may be that the only way to truly gel as a team would be in person.
I am not as willing to write off good and intelligent people as overego'd.
I may be incorrect in that, but I hope not.
Jn
Didn't I just say that?
Jn
Edit:I suspect you answered before I could finish my post. I have to save my posts about every two minutes or the iPad times out of forum and I lose everything.
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Please compare AM modulation in general and modulation index to the suppressed carrier case. Hans' plot is a general AM modulation not suppressed carrier. You keep referencing the trig identity that has no carrier present in the output.
I havent been here long enough then. It is more validation to me, however.
Seems with the new good behaviour rules, things move along more smoothly on the point(s).
-RNM
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Re-read my post. I already stated that.
My point still stands. 20/4 is sin20cos4....shorthand here.
Compare a 20/4 filtered to remove upper sideband to 18/2 unfiltered.
In time, not FFT.
And please provide an explanation as to why Han's sends in 20k raised sine and outputs 18k. His very own outputs are frequency changed.
Jn
I'll check the data out on the weekend, but repeatedly calling Hans "Han's" is subconsciously driving me nuts 🙂. I'm guessing you're using a phone or tablet and it's autocorrecting you improperly rather than you not knowing that Hans is a name.
Jn, what do you mean by email link? 😕
If you want to contact Ms. Melchior, her email is on the first page of the document. If you want to have a copy of PDF file, just right-click on the 'View PDF' tab on that web page and 'save as'.
That’s correct.
In hindsight having signal content around 20Khz at the same frequency where the Brick Wall filtering took place was probably not ideal with the sample length of only 20msec.
Because of that, a frequency residue right below 20Khz remains still there which might confuse.
Hans
Thank you for your full answer and for taking my question in the spirit it was intended.
As you mention in a subsequent post, the environment is different on an online forum, and maybe people find it easier to walk away when they feel a little browbeaten? 😱 it could also be a cultural thing, anyway, moving on from that.
I am no expert in any of the things talked about here, I'm just an average person working in my garage/basement 😉 perhaps that gives me a certain advantage. I can listen to all the arguments with a certain open-mindedness and try to understand.
I pointed orjan to KSTR's posts because personally I found his explanations of what and why we are seeing in the time domain the clearest. A number of people, me included in my amateur way, have tried to explain how looking in the time domain for what appear to be frequency shifts is not the right way to go about it.
I asked you whether there was anything new being shown or discussed here, it seems to me the next logical step would be to prove there is a frequency shift, and whilst you think you have done that, I don't think you have....... please bear in mind I'm not an expert 🙂
Thanks for your feedback, but why do you think the heading is wrong ?
The signal that's in the image on the lwr left has been brick wall filtered at 20Khz and shown on the lwr right, I don't see anything that's wrong.
Hans