Being a "full blown" hub also (as far as I know) lifts the tight timing limitations as you can insert the filtering logic between the host-side and the device-side (something you can't do witch IC-based hub chips). However noone says you can't implement a legitimate USB hub that presents itself in the device tree and uses transaction translators (TTs) for split transfers for USB1.1 devices. (It's quite a few analog-logic-based steps. IIRC the problem was doing it sufficiently fast to meet the few-nanosecond limit between two endpoints and achieve transparency. Its better to prevent the toilet overflowing then having to deal with the Crap on the floor afterwards!Ĭlick to expand.Well, it's a bit more complicated than USB1.0 or 1.1, but not impossible. You can measure this noise on the DAC's ground plane - and this is the root problem that even a single logic gate operating will inject noise onto a Ground plane - so you don't want this logic Gate to be "processing" any data pattern that has unwanted phase noise encoded onto it. sometime and I can demonstrate the kind of artefacts that need to be dealt with - I have real time spectrum analysers that can perform 3GHz real-time FFT spans of the RF energy - its horrifying, sometimes your not even sure where to start. Your welcome to visit my lab here in Czech Rep. the Phase noise of the data is really really bad! PC's are designed just to work, without any regards to how much unwanted energy they spew out - just as long as they conform to EMC regulations. If you do not allow these cookies, you will experience reduced relevant content.Click to expand.Yes - this is the fundamental problem the Phase noise of the jitter spectrum is heavily modulated by what ever the Host USB device happens to be processing, its PSU noise, and mixed in with the Audio Data - a whole "bucket load of crap". They do not store directly personal information, but are based on uniquely identifying your browser and internet device. They may be used by Analog Devices to build a profile of your interests and show you relevant content on our site. Targeting Cookies: These cookies may be set through our site by Analog Devices and our service providers. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance. All information these cookies collect is aggregated and therefore anonymous. They help us to know which pages are the most and least popular and see how visitors move around the site. Performance Cookies: These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. If you do not allow these cookies then some or all of these services may not function properly. They may be set by us or by third party providers whose services we have added to our pages. Functional Cookies: These cookies enable the website to provide enhanced functionality and personalization. These cookies do not store any personally identifiable information. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. Strictly Necessary Cookies: (Always Active) These cookies are necessary for the website to function and cannot be switched off in our systems. After we finish updating our website, you will be able to set your cookie preferences. Analog Devices is in the process of updating our website.
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