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Old 6th July 2018, 08:32 AM   #111
chris719 is offline chris719  United States
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Location: Connecticut
Quote:
Originally Posted by JPS64 View Post
As promised.


The reference of the DRAKA (Prysmian Group) is F 4709-17.


Test equipment:
- 2GHz Oscilloscope 10GS/s WAVERUNNER 204Xi LECROY
- Active Differential Probe WL300 LECROY
- USB Test Fixture TF-USB LECROY



According USB-IF compliance program (http://www.usb.org/developers/compliance/):
--> Overall result: pass!
- Signal eye: eye passes
- EOP width: 7.89 bits: EOP width passes
- Measured signaling rate: 480.0834 MHz: signal rate passes
- Rising Edge Rate: 1005.11 V/us (636.74 ps equivalent risetime): passes
- Falling Edge Rate: 974.79 V/us (656.55 ps equivalent risetime): passes
- Consecutive jitter range: -81.928 ps to 131.408 ps, RMS jitter 49.613 ps
- Paired JK jitter range: -55.155 ps to 59.024 ps, RMS jitter 16.807 ps
- Paired KJ jitter range: -65.229 ps to 61.868 ps, RMS jitter 16.529 ps


Images attached.


ESD protection is RCLAMP0502N.


EMI CMC is DLW21S.


JP
Nice, I have used that same common-mode choke on a USB interface (different ESD protection though). They are missing from many audio designs.
 
Old 6th July 2018, 09:12 AM   #112
mmerrill99 is offline mmerrill99
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Quote:
Originally Posted by chris719 View Post
Nice, I have used that same common-mode choke on a USB interface (different ESD protection though). They are missing from many audio designs.
And why do you think a CM choke is needed? Because the cable is carrying high speed USB differential signalling & the cable CAN INDUCE CM noise at the USB receiver IC - it's not simply transmitted from the source. Therefore in this one factor alone USB cables can differ, never mind all the other factors

Last edited by mmerrill99; 6th July 2018 at 09:22 AM.
 
Old 6th July 2018, 09:36 AM   #113
chris719 is offline chris719  United States
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Quote:
Originally Posted by mmerrill99 View Post
And why do you think a CM choke is needed? Because the cable is carrying high speed USB differential signalling & the cable CAN INDUCE CM noise - it's not simply transmitted from the source. Therefore in this one factor alone USB cables can differ, never mind all the other factors
It might be needed to pass emissions or immunity testing on a case by case basis. A nice to have if you don't have signal integrity problems with it populated. I'd use it, but highly doubtful it has any measurable impact on the analog output. You still have yet to describe the mechanism by which this ends up in the analog output on a piece of correctly designed gear.

There are specs for USB cables you know? They specifically discuss things like the required shield construction, twist pitch, etc.

Maybe you should get in the audiophile Ethernet cable business before that blows up.
 
Old 6th July 2018, 09:56 AM   #114
mmerrill99 is offline mmerrill99
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Quote:
Originally Posted by chris719 View Post
It might be needed to pass emissions or immunity testing on a case by case basis. A nice to have if you don't have signal integrity problems with it populated. I'd use it, but highly doubtful it has any measurable impact on the analog output.
You now have altered your argument to admitting that there are difference between cables but doubt they have any "measurable impact on the analog output." Very interesting shift from your first rant about this

So, what is the effect of CM noise in audio? Have you ever measured the effect of cm noise on a DAC's analogue output?
Quote:
You still have yet to describe the mechanism by which this ends up in the analog output on a piece of correctly designed gear.
I don't have to describe anything other than the possible differences between USB cables, as I have done. As I stated from the start I have heard some differences with ferrite clamps on USB cables & a USB cable (not designed for audio) designed ferrite compound wrap

Quote:
There are specs for USB cables you know? They specifically discuss things like the required shield construction, twist pitch, etc.
Yes, there are USB specs which are meant to ensure a certain level of reliability in USB digital signal delivery. Tell us what it says about shield construction & twist pitch in the USB specs

Last edited by mmerrill99; 6th July 2018 at 09:58 AM.
 
Old 6th July 2018, 11:38 AM   #115
chris719 is offline chris719  United States
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Quote:
Originally Posted by mmerrill99 View Post
You now have altered your argument to admitting that there are difference between cables but doubt they have any "measurable impact on the analog output." Very interesting shift from your first rant about this

So, what is the effect of CM noise in audio? Have you ever measured the effect of cm noise on a DAC's analogue output? I don't have to describe anything other than the possible differences between USB cables, as I have done. As I stated from the start I have heard some differences with ferrite clamps on USB cables & a USB cable (not designed for audio) designed ferrite compound wrap

Yes, there are USB specs which are meant to ensure a certain level of reliability in USB digital signal delivery. Tell us what it says about shield construction & twist pitch in the USB specs
I haven't shifted at all on cables. You can continue tilting at windmills. A total non issue in gear that is correctly designed. You can find the USB cable specifications on Intel's website.
 
Old 6th July 2018, 11:45 AM   #116
mmerrill99 is offline mmerrill99
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Quote:
Originally Posted by chris719 View Post
I haven't shifted at all on cables. You can continue tilting at windmills. A total non issue in gear that is correctly designed. You can find the USB cable specifications on Intel's website.
OK, no problem you don't want to back up what you say & just want to rant
 
Old 6th July 2018, 11:53 AM   #117
Scottmoose is offline Scottmoose  United Kingdom
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Guys -may I make a suggestion / observation:

You have been baited into a worthless debate by an OP who makes a practice of this kind of thing. 6 months or so ago, he was whiling away his time in a thread on the loudspeakers forum essentially trying to claim AC is not alternating, that all electrical circuits are created based on Spice models (including those created before electronic computers even existed), and that a given loudspeaker crossover will behave differently if a series component were placed in the nominal positive or negative leg (no changes to electrical component order, and independent of external influences e.g. mutual inductance interactions which is a matter of board layout / component configuration rather than the electrical topology of the circuit). No support, no evidence (hardly surprising in the circumstance), just hand-waving twaddle and a rapid exit when pressed for his claimed evidence. Same modus operandi here. Paraphrasing only slightly, any of these phrases ring a bell?

-'I've... read some books [titles unspecified] & it's too complex to explain'
-'I think'
-'I believe'
-'You need to prove [despite being the one making claims -a favoured inversion of this type of troll on-line, in print or in debate]'

Do yourselves a favour: don't fall for it any further. Let the thread die now.
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Old 6th July 2018, 11:56 AM   #118
cacao ambiance is offline cacao ambiance  United Kingdom
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I had trouble with bad USB cables when re-flashing the bootloader on my android mobile. I had some "samsung" cables but they failed. The only ones that worked reliably where my Anker | #UseAnkerInstead usb cables.

idk the details of reflashing bootloader but i guess its more sensitive/less or no error correction, hence the problem. i had not noticed previous use of the bad cables being a problem with day to day use.

Note that reflashing bootloader was a low level operation. so its different from a normal full OS.

This problem of bad cables caused me a lot of lost time in asking my self, "Oh Why is it not working!" It was only when someone on the IRC help channel encouraged me to try a different usb cable i found that was the problem.

Last edited by cacao ambiance; 6th July 2018 at 12:00 PM.
 
Old 6th July 2018, 12:44 PM   #119
Pano is offline Pano  United States
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Quote:
Originally Posted by andy2 View Post
Seems like lots of people still missing the point of the argument. Some still arguing like a little children. Well, I am moving on to better things.
LOL. That's one of the laziest cop-outs I've ever seen. You started this whole mess, and now you leave. Was your plan just to stir the pot then leave when it got to hot for you? Scottmoose sums it up perfectly above.

Well at least we can hope some people learned a little about how digital interconnects work - and don't work.
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