USB sucks
And for all those who put BS on this board, just grab this before making a fool of you... https://www.amazon.com/Principles-Digital-Communication-Robert-Gallager/dp/0521879078 |
@herman "Transmitting audio data in realtime is not the same as transferring TeraBytes of data files. You should look into it before making such statements." https://darko.audio/2016/05/gordon-rankin-on-why-usb-audio-quality-varies/ I will defer to Gordon Rankin who I trust more than somebody angrily ranting on this forum The three main USB transmission protocols are Bulk, Interrupt and Isochronous. Bulk (used for data transfer to a hard drive) and Interrupt are error-correcting. Isochronous (used for audio) is not.” “Bulk and Interrupt are immediately NAK (negative acknowledgement). The receiver is designed to detect a bad packet immediately and the packet is resent.” “For USB audio, the receiving device is basically translating a serial stream of data with a clock interwoven throughout. At the end of the packet sits some sort of block check. If the block check does not match the data then that packet is flagged as an error.” “With Isoschronous USB transmission, packets are sent without any error correction / resending. But guess what? This is the USB protocol used for audio frames. The bad news is they are not error-free. The good news is these Isochronous frames are afforded the highest priority in the system.” |
@jaytor sed:
I think what @rixthetrick was getting at is that any signal on a cable is inherently analogHow's that? With all due respect, do you actually understand what makes analog signals analog and how digital signals are different. ABout the only similarity is that they can both use wire as a transport media. If a car operates on roads and a elephant walks down the same road, does that make the elephant a car? |
Sorry, back to the difference in sending data over USB like we do with file transfers and audio uses.. to further my point above , despite what the angry poster says, .Audio and file transfers are different as file transfer protocols have error correction from Mojo Audio
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@jaytor sed:I think what @rixthetrick was getting at is that any signal on a cable is inherently analogHow’s that? With all due respect, do you actually understand what makes analog signals analog and how digital signals are different. ABout the only similarity is that they can both use wire as a transport media. If a car operates on roads and a elephant walks down the same road, does that make the elephant a car? It depends on how you look at it. "The only similarity is that they can both use wire" isn’t quite right. Digital is by definition binary.... high/low, 1/0, true/false, whatever. Electrically, those 2 states can be represented by 2 different frequencies, 2 phases, etc. . With USB those 2 digital states are 2 voltage levels. Analog information is represented by constantly changing voltage levels with an infinite number of possibilities. So yes, they are the same in that both analog and digital information are represented by voltage levels. Since the digital voltage level can’t change instantaneously (a perfect square wave) it bears some resemblance to an analog signal’s infinite voltage levels. However, does any of that really matter? With analog, errors are a given. It is impossible to maintain 100% accuracy throughout the analog chain. On the other hand, digital errors are very, very low and in a well designed system, for all practical purposes they are zero. In any case, it is a red herring that distracts from the topic of whether or not USB sucks BTW.... it does not |
