GG1

dewme said:

canukstorm said:

"Wireless charging pads use electromagnetic induction to juice up your phone. Both the pad and your phone contain wire coils: the pad draws current from the wall and runs it through the coil, creating an electromagnetic field. That field induces an electric current in your phone’s wire coil, which it uses to charge the battery.

However, the electricity being transmitted to your phone isn’t perfectly clean or ideal. It generates some noise, which can interfere with other wireless devices. That’s why the FCC (and regulatory bodies in other countries) set strict limits on wireless emissions.

Noise from a single coil might not be a problem, but each charging coil generates a slightly different waveform. When those waves overlap, the constructive interference intensifies their strength. Just like when two ocean waves collide and combine their height, radio frequencies can combine their intensity as they interact.

Managing these overlapping harmonic frequencies is incredibly challenging, and gets harder the more coils that you are integrating. From patent filings, it looks like Apple’s ambitious plan was to use considerably more coils than other charging pads on the market.

Rumors speculated that Apple was considering up to 32 coils—up from the fifteen shown in their conceptual patent filing.

Other multi-device wireless chargers place two or three coils side-by-side, but require you to fiddle with your phone to find the “sweet spot” over one coil for it to start charging. With AirPower, Apple was trying to create one large charging surface using overlapping coils, allowing it to power multiple devices from anywhere on the mat. But that introduces multiple challenges.

We asked an engineer with experience building wireless charging systems what obstacles Apple was working to overcome. “Over time, these harmonics add up and they become really powerful signals in the air,” explains William Lumpkins, VP of Engineering at O & S Services. “And that can be difficult—that can stop someone’s pacemaker if it’s too high of a level. Or it could short circuit someone’s hearing aid.” If Apple’s multi-coil layout was spinning off harmonics left and right, it’s possible AirPower couldn’t pass muster with US or EU regulations."

https://ifixit.org/blog/14883/what-finally-killed-airpower/

This makes sense. What is being described regarding electromagnetic interference is also what's known as superposition which is also the basis for beamforming, both for electromagnetic and physical (sound pressure). When properly engineered, beamforming can be used constructively to overcome the limitations described, but with some caveats. If Apple could detect the physical orientation of a device on the pad it could employ many smaller micro-coils and beamforming to replicate the same electromagnetic field that would be formed by a single larger coil in a conventional charger that has physical mechanisms like a cradle to ensure device orientation. It would be fairly straightforward to design a charging pad with many smaller micro-coils that optimizes the charging of a single device - iff the charging pad can determine or coerce the orientation of the device on the pad. But even this would be far from ideal because it would still be open-loop. If the device being charged were able to communicate back to the charging pad about the quality of the charging process the charging pad could auto-tune itself to the charging requirements and reduce spurious interference and shutdown unnecessary coils. Without device orientation detection and a feedback loop it's difficult to come up with a solution that works effectively. The feedback loop could be done out-of-band using NFC, but you can now see that this starts to ratchet up the complexity and cost and you have to ask yourself whether it's even worth it.

My feeling is that this problem is fully resolvable but not without advances in wireless charging technology on both sides. Trying to solve it on one side, i.e., smart charging pad, with no similar level of advancement on the device side is a severe constraint. Ultimately, if both the charging mat and devices have arrays of micro-coils and advanced beamforming it would be possible to selectively steer the charging beam to the device being charged and auto-tune the power needed based on the device also using beamforming on its side with a feedback between the charger and the device. Theoretically you could nix the pad completely and allow devices to be charged from across the room, say from a transmitter mounted in the ceiling that charges every device in the room. But every step down the path to the theoretical solution needs to be gated by the question: is this really worth the cost and effort?   

AppleInsider said:

It appears that Mac users looking to boost their workflow with an RX 560 will have to deal with a few limitations.

Apple notes playback of HDCP-protected content from iTunes and certain unnamed streaming services is not supported on displays directly connected to an RX 560-based eGPU, including Sonnet's device. Said content can, however, be viewed on the built-in display of a MacBook Pro, MacBook Air and iMac, the document reads.

gatorguy said:

blastdoor said:

It could be that this just means Apple doesn't intend to start supporting 5G in 2020. 

I'm no expert, but 5G sounds really weird to me for use in a phone. I've read that you basically need line of sight in order for it to work. If anything --- *anything* -- solid comes between your phone and the "tower" (probably not really a tower), then you either lose the signal or it's degraded to the point that you might as well have just stuck with LTE. 

"Fixed wireless broadband service based on 5G technology will not require line of sight between the transmitter and receiver, said Verizon CEO Lowell McAdam today. Advances in antenna and processing technology have essentially eliminated the need for fixed 5G line of sight, he explained in a question-and-answer session at a financial conference, where he also provided additional detail about Verizon network densification plans to support 5G and other offerings."

There's also an easy-to-understand tutorial about the whole 5G thing, what it is, what it's for, where you'll find it, and how soon here:
https://www.digitaltrends.com/mobile/what-is-5g/

MplsP said:

A wifi chip for the HomePod is very different from what's needed for a smart phone. Chip size, power efficiency, signal sensitivity/amplification and universal (CDMA) compatibility are all areas where Qualcomm has an advantage. I'd like nothing better than for Apple to screw Qualcomm, but unfortunately they have the best chips right now, making it difficult for any manufacturer to ditch them without making sacrifices.