利用超声波传输数据 [英] Transfering data using ultrasound
问题描述
<一个href="http://www.engadget.com/2010/12/20/yamaha-infosound-prototype-talks-to-your-phone-as-you-zone-out-d/">Yamaha InfoSound 和 ShopKick应用使用技术，使为传输数据使用超声波。正在播放一个听不见的信号（> 18KHZ），可拾起现代手机（IOS，Android的）。
Yamaha InfoSound and ShopKick application use technologies that allow to transfer data using ultrasound. That is playing an inaudible signal (>18kHz) that can be picked up by modern mobile phones (iOS, Android).
什么是这种技术使用的方法？他们使用什么样的调制？
推荐答案
我看到一些问题，这种方法。首先，18KHZ是的没有的听不见。很多人不能听到它，特别是因为他们的年龄，但我知道我肯定能（我常做听力测试，与工作相关的）。此外，大多数的手机对他们 A / D转换器和许多不同的低通滤波器设备，尤其是较旧的Android的那些（我亲眼看到这种情况发生），过滤低于16千赫左右一切。您的应用程序，因此不保证工作在任何硬件。 iPhone的也许应该是能够做到这一点。
I see several problems with this approach. First, 18kHz is not inaudible. Many people cannot hear it, especially as they age, but I know I certainly can (I do regular hearing tests, work-related). Also, most phones have different low-pass filters on their A/D converters, and many devices, especially older Android ones (I've personally seen that happen), filter everything below 16 kHz or so. Your app therefore is not guaranteed to work on any hardware. The iPhone should probably be able to do it.
在调制方面，它可以是任何东西真的，但我肯定会排除AM。声音有接零的鲁棒性，当谈到卷。如果我要实现类似的东西，我会去 FSK 。我认为 PSK 会失败，由于声波的反射和这样的。困难的是，你正在使用中的一个很窄的带宽不稳健的能量转移。我当然不怀疑，就可以实现的，但我没有看到这样的事情证明可靠。只是恕我直言，那是。
In terms of modulation, it could be anything really, but I would definitely rule out AM. Sound has next to zero robustness when it comes to volume. If I were to implement something like that, I would go with FSK. I would think that PSK would fail due to acoustic reflections and such. The difficulty is that you're working with non-robust energy transfer within a very narrow bandwidth. I certainly do not doubt that it can be achieved, but I don't see something like this proving reliable. Just IMHO, that is.
更新：现在我想想，通断的纯将与一个单一的色调，如果你不传输任何数据，只是一些短期的信号
Update: Now that i think about it, a plain on-off would work with a single tone if you're not transferring any data, just some short signals.
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