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PostPosted: Mon Aug 25, 2014 7:32 pm 
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Muriel
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Kuei Yang Wang wrote:
Lucky my dinner was not like that...


https://www.youtube.com/watch?v=anwy2MPT5RE

Do you want some spam with that...

Ciao T

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PostPosted: Mon Aug 25, 2014 7:48 pm 
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Muriel
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Andrew,

ball3901 wrote:
You are right, and have always been right. This isn't DSD anymore.


No, I never right. I never said outright, unqualified X is not X but Y.

I did ask questions like: If X * 2 = 2 X and with your method I am getting 3 Y, how can you call it identical? That is just a question...

ball3901 wrote:
Best case? Maybe. Seems to be the best chance we have with the digital filtering. Higher sample rate, gentler slopes = better impulse response and less ringing. In theory, anyway.


Well, in theory you will find that theory and practice are the same. In practice, you find they are not.

My theory has always lagged behind my practice.

To me - best case - cut a juicy ribeye or filet steak, sear it on real fire (gas, covered to reduce cancer risk), add salt, maybe pepper. Eat. I love MEAT. Maybe a tater or two on the side, some carrots etc, Mushrooms or aspargus grilled.

To me - worst case - use a high pressure water jet to strip leftover meat off the bones, process that with gelatine and sorts of artificial additions, mix it by machine and form the result into blocks held together by the gelatine extracted from the bones, pack it into a tin and sell it as "better than real meat".

Hey, I am not being judgemental, just stating preferences. On my balcony 19 Floors up with a balcony bigger than many city folks living rooms I love cutting my fillet steaks 2" thick and wrap them into the fatty part of Italian prosciutto ham. Who am I to look down at anyone who considers a Big Mac a splendid meal?

Just don't ask me to swap places.

Ciao T

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PostPosted: Mon Aug 25, 2014 7:54 pm 
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Muriel
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Andrew,

ball3901 wrote:
Make of it what you will.


Wrong, you make it whatever you will...

============================================================

Now Look What You Made Me Do!

from The Golden Apple
by Robert Shea & Robert Anton Wilson


What really happened was that everybody was squabbling over the apple and working up a sweat and pushing one another around and pretty soon their vibrations -- Gods have very high vibration, exactly at the speed of light, in fact -- heated up the apple enough to unleash some heavy fumes. In a word, the Olympians all got stoned.

And they saw a Vision, or a series of Visions.

In the first Vision, they saw Yahweh, a neighboring god with a world of his own which overlapped theirs in some places. He was clearing the set to change its valence and start a new show. His method struck them as rather barbarous. He was, in fact, drowning everybody -- except one family that he allowed to escape in an Ark.

"This is Chaos," said Hermes. "That Yahweh is a mean mother', even for a god."

And they looked at the Vision more closely, and because they could see into the future and were all (like every intelligent entity) rabid Laurel and Hardy fans and because they were zonked on the weed, they saw that Yahweh bore the face of Oliver Hardy. All around him, below the mountain on which he lived (his world was flat), the waters rose and rose. They saw drowning men, drowning women, innocent babes sinking beneath the waves. They were ready to vomit. And then Another came and stood beside Yahweh, looking at the panorama of horrors below, and he was Yahweh's Adversary, and, stoned as they were, he looked like Stanley Laurel to them. And then Yahweh spoke, in the eternal words of Oliver Hardy: "Now look what you made me do," he said.

And that was the first Vision.

They looked again, and they saw Lee Harvey Oswald perched in the window of the Texas School Book Depository; and he, again, wore the face of Stanley Laurel. And because this world had been created by a great god named Earl Warren, Oswald fired the only shots that day, and John Fitzgerald Kennedy was, as the Salvation Army charmingly expresses it, "promoted to glory."

"This is Confusion," said Athena with her owl-eyes flashing, for she was more familiar with the world created by the god Mark Lane.

Then they saw a hallway, and Oswald-Laurel was led out between two policemen. Suddenly Jack Ruby, with the face of Oliver Hardy, stepped forward and fired a pistol right into that frail little body. And then Ruby spoke the eternal words, to the corpse at his feet: "Now look what you made me do," he said.

And that was the second Vision.

Next, they saw a city of 550,000 men, women and children, and in an instant the city vanished; shadows remained where the men were gone, a firestorm raged, burning pimps and infants and an old statue of a happy Buddha and mice and dogs and old men and lovers; and a mushroom cloud arose above it all. This was a world created by the cruelest of all gods, Realpolitik.

"This is Discord," said Apollo, disturbed, laying down his lute.

Harry Truman, a servant of Realpolitik, wearing the face of Oliver Hardy, looked upon his work and saw that it was good. But beside him, Albert Einstein, a servant of that most elusive and gnomic of gods, Truth, burst into tears, the familiar tears of Stanley Laurel facing the consequences of his own karma. For a brief instant, Truman was troubled, but then he remembered the eternal words: "Now look what you made me do," he said.

And that was the third Vision.

Now they saw trains, many trains, all of them running on time, and the trains criss-crossed Europe and ran 24 hours a day, and they all came to a few destinations that were alike. There, the human cargo was stamped, catalogued, processed, executed with gas, tabulated, recorded, stamped again, cremated and disposed.

"This is Bureaucracy," said Dionysius, and he smashed his wine jug in anger; beside him, his lynx glared balefully.

And then they saw the man who had ordered this, Adolf Hitler, wearing still the mask of Oliver Hardy, and he turned to a certain rich man, Baron Rothschild, wearing the mask of Stanley Laurel, and they knew this was the world created by the god Hegel and the angel Thesis was meeting the demon Antithesis. Then Hitler spoke the eternal words: "Now look what you made me do," he said.

And that was the fourth Vision.

They did then look further and, lo, high as they were they saw the founding of a great republic and proclamations hailing new gods named Due Process and Equal Rights for All. And they saw many in high places in the republic form a separate cult and worship Mammon and Power. And the Republic became an Empire, and soon Due Process and Equal Rights for All were not worshipped, and even Mammon and Power were given only lip-service, for the true god of all was now the impotent What Can I Do and his dull brother What We Did Yesterday and his ugly and vicious sister Get Them Before They Get Us.

"This is Aftermath," said Hera, and her bosom shook with tears for the fate of the children of that nation.

And they saw many bombings, many riots, many rooftop snipers, many Molotov cocktails. And they saw the capital city in ruins, and the leader, wearing the face of Stanley Laurel, taken prisoner amid the rubble of his palace. And they saw the chief of the revolutionaries look about at the rubble and the streets full of corpses, and they heard him sigh, and then he spoke the eternal words: "Now look what you made me do," he said.

And that was the fifth Vision.

And now the Olympians were coming down and they looked at each other in uncertainty and dismay. Zeus himself spoke first.

"Man," he said, "that was Heavy Grass."

"Far fuckin out," Hermes agreed solemnly.

"Tree fuckin mendous," added Dionysius, petting his lynx.

"We were really fuckin into it," Hera summed up for all.

Heavy Grass...

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PostPosted: Mon Aug 25, 2014 8:06 pm 
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Lol.... too much good stuff!


Okay, one more question.

FIR filtering of 1 bit DSD. In the Analog domain, one can say the output is multi-bit DSD. Like we have talked about before, in the Burr Brown, signalyst, etc.

What about the digital domain? Has anyone been able to, or is it possible to model a digital version of the filter? That would give us parallel streams of DSD? And if you could do that, would that be an editable format?

Thanks as always

Andrew


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PostPosted: Mon Aug 25, 2014 8:22 pm 
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Muriel
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Hi,

ball3901 wrote:
Lol.... too much good stuff!


Use it...

ball3901 wrote:
FIR filtering of 1 bit DSD.


Is for all intents and purposes the same as FIR filtering and analogue signal, except S/H is self contained.

ball3901 wrote:
In the Analog domain, one can say the output is multi-bit DSD. Like we have talked about before, in the Burr Brown, signalyst, etc.


This is mainly about semantics and how to interpret it, it changes noting at the hardware/software level.

ball3901 wrote:
What about the digital domain?


It is the same as the analogue domain, except in most practical cases less resolution?

ball3901 wrote:
Has anyone been able to, or is it possible to model a digital version of the filter?


The fundamental point is that this filter uses a delay chain. Easily emulated.

ball3901 wrote:
That would give us parallel streams of DSD?


Given that "parallel streams of DSD"are not DSD and not PCM, who knows.

Looks to me time for another MP Moment:

It is just a flesh wound...

https://www.youtube.com/watch?v=-6VTci1Bunk

Ciao T

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PostPosted: Tue Aug 26, 2014 1:03 am 
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Okay, T, so here is a really crazy question. Or maybe not so crazy..

You can filter DSD in either the digital or analog domain. Mytek is quick to point out that the digital filter performs the same function as the analog fitler in SACD/DSD systems.

If the digital filter is so great, why not just stop there?

Couldn't you just digitally filter DSD, take the multibit output at whatever sample rate, send it to switches, and be done with it? Essentially the same as native DSD conversion, you just moved the FIR filter from the analog domain into the digital. Why all this extra stuff? ASRC's, remodulation, and then you have to analog filter it again anyway?


I guess all that extra stuff is supposed to make things better. I dunno, though.

Keeping it simple seems pretty smart to me. Oh, and about that. Digital vs Analog filter. If you built a digital FIR filter that was the same slope and corner of the filter in the DSD1793, how would its performance compare? Could you match the impulse response/ringing performance in the digital domain?

Andrew


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PostPosted: Tue Aug 26, 2014 5:30 am 
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Muriel
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Hi,

ball3901 wrote:
You can filter DSD in either the digital or analog domain. Mytek is quick to point out that the digital filter performs the same function as the analog fitler in SACD/DSD systems.


Alas as we both know, you cannot perform digital filtering that has a DSD stream in and a DSD stream. The Output must have many levels.

ball3901 wrote:
Couldn't you just digitally filter DSD, take the multibit output at whatever sample rate, send it to switches, and be done with it?


Not really. You cannot use a very low number of bitswitches. Try using a Multibit DAC, then things look different.

So we can convert DSD to multi-bit PCM and apply filtering in the process. We can then play the PCM back without extra oversampling.

But that is the same as letting your computer convert DSD to PCM, likely with a better result than the hardware filtering.

In this case we can just dump any DSD support in the DAC as well. My home system still plays DSD in this precise way, becausethe DAC does not support DSD.

ball3901 wrote:
Essentially the same as native DSD conversion, you just moved the FIR filter from the analog domain into the digital.


If that is "native DSD conversion" than using my PC to convert to PCM and playing the result as PCM is also equal to "native DSD".

ball3901 wrote:
Keeping it simple seems pretty smart to me. Oh, and about that. Digital vs Analog filter. If you built a digital FIR filter that was the same slope and corner of the filter in the DSD1793, how would its performance compare? Could you match the impulse response/ringing performance in the digital domain?


Presuming your DAC following that filter is really good, sure, why not.

Ciao T

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PostPosted: Tue Aug 26, 2014 11:33 am 
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Cow

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Kuei Yang Wang wrote:
ball3901 wrote:
Couldn't you just digitally filter DSD, take the multibit output at whatever sample rate, send it to switches, and be done with it?


Not really. You cannot use a very low number of bitswitches. Try using a Multibit DAC, then things look different.

So we can convert DSD to multi-bit PCM and apply filtering in the process. We can then play the PCM back without extra oversampling.

But that is the same as letting your computer convert DSD to PCM, likely with a better result than the hardware filtering.

In this case we can just dump any DSD support in the DAC as well. My home system still plays DSD in this precise way, becausethe DAC does not support DSD.




Maybe something hit me in the head overnight, but, I just don't see the benefit once you have filtered that DSD stream into multi-bit, in returning it to 1 bit. Or however many levels of 1 bit. Maybe I was wrong about the whole 'best case' scenario. Seems that the two best cases would be the most simple ones.

1. Single analog filter at end of chain.

2. Single digital filter, convert as PCM (real PCM, of course)


But, just for fun, what would it take to directly convert, say, the DSD-wide intermediate format? 8 bit, 2.8mhz? After all, it is essentially high sample rate, noise-shaped PCM. Why not 256 thermometer coded switches?


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PostPosted: Tue Aug 26, 2014 4:51 pm 
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Muriel
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Hi,

ball3901 wrote:
Maybe something hit me in the head overnight, but, I just don't see the benefit once you have filtered that DSD stream into multi-bit, in returning it to 1 bit.


Same here. That is the issue. You touch the DSD stream in any way, you might as well make it 2xDXD or something similar.

But then, why not use superior ADC's to record "beyond single bit" in the first place. How about 18 Real Bits (SAR-ADC) at 5MSPS? that would allow 4 X Oversampling if outputting in 705.6/768KHz or 20Bit output.

Seems that the two best cases would be the most simple ones.

ball3901 wrote:
1. Single analog filter at end of chain.

2. Single digital filter, convert as PCM (real PCM, of course)ouch


Yup. I would say BB's FIR analogue filter is inbetween, but much closer to 1...

ball3901 wrote:
But, just for fun, what would it take to directly convert, say, the DSD-wide intermediate format? 8 bit, 2.8mhz? After all, it is essentially high sample rate, noise-shaped PCM. Why not 256 thermometer coded switches?


There are a lot of things that fall under the Beavers view (from "The Hunting of the Snark") of "if that could but be done":

"The Beaver had counted with scrupulous care,
Attending to every word:
But it fairly lost heart, and outgrabe in despair,
When the third repetition occurred.

It felt that, in spite of all possible pains,
It had somehow contrived to lose count,
And the only thing now was to rack its poor brains
By reckoning up the amount.

"Two added to one—if that could but be done,"
It said, "with one's fingers and thumbs!"
Recollecting with tears how, in earlier years,
It had taken no pains with its sums."

Ciao T

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PostPosted: Tue Aug 26, 2014 8:30 pm 
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Cow

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Kuei Yang Wang wrote:
Hi,



ball3901 wrote:
1. Single analog filter at end of chain.

2. Single digital filter, convert as PCM (real PCM, of course)ouch


Yup. I would say BB's FIR analogue filter is inbetween, but much closer to 1...




And the reason the BB variant is inbetween? Perhaps because it can be interpreted as multi-level on the output? Difference being, we are talking continuous vs discrete? Or maybe we are talking about the logic inside the chip itself? As in, it isn't as direct a signal path as is possible?


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PostPosted: Wed Aug 27, 2014 2:32 am 
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Ah! I think I may get it...

The nuance is RC filter vs (more complex?) FIR filter?


Single switch output into an RC filter is the, well, simplest way to go. FIR filter= a little different bird, whether digital or analog.


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PostPosted: Wed Aug 27, 2014 8:44 pm 
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LOL at myself. Openly speculating on things I know nothing about. Filters= math. I barely passed 8th grade math.


Anyway, continuing with the exercise that has gone on for several posts now, I think I understand a little more.

BB FIR filter for DSD. In order for the filter to work, 1-bit DSD has to be "transformed" into 8 bit/9level thermometer coding. Dynamic Element Matching is performed at the same time...

Or, like with the Signalyst DAC, 32bit/33 level thermometer coding, DEM, etc. etc. etc.

It is actually quite similar to multi-bit delta sigma conversion, so it seems.


Now, for the laymen like me, it is sufficient to say DSD D/A conversion is accomplished with an analog FIR filter. Forget the bits, levels, shift registers, element matching, etc. etc.


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PostPosted: Thu Aug 28, 2014 12:44 am 
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Thorsten,


Inverted Complementary Offset Binary? Is this a form of 'thermometer code?" Datasheet says that is what the DSD1793 is using?


And, since my curiosity is getting the best of me, exactly how is the Delta Sigma part of the DSD1793 segment DAC combined with the 'PCM' part? Datasheet seems to say that they 'overlap' into a 0-66 level code, that is dynamic element matched, then converted to analog?

Ehhh.. on second thought, maybe not. Too much for me!!


Thanks

Andrew


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PostPosted: Thu Aug 28, 2014 2:58 am 
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And one last one before I am done....

Just discovered google patent search. BAD IDEA FOR ME. Now I have a wealth of more stuff to pore over.

Seems like the FIR used by Burr Brown, yes is analog, but, could it be more specifically called a 'semi-digital', or a 'semi-analog' filter?

Some of the patents I have been reading (ESS, AMD, TI, etc,etc) describe the 'semi' FIR filter in such a way that sounds very, very similar to your description of the BB filter...


Thanks, and I swear I am done.. for now.

Andrew


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PostPosted: Thu Aug 28, 2014 4:35 pm 
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AHA!!!

I am glad I found this 'diagram' As one of those left-handed, right brained people, I am excessively visual, and this was most helpful.

http://www.accuphase.com/cat/dp-700_e.pdf


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