使用超声波传输数据 [英] Transferring data using ultrasound

问题描述

Yamaha InfoSound 和 ShopKick应用程序使用的技术允许使用超声波传输数据。这是一个听不见的信号（> 18kHz），可以通过现代手机（iOS，Android）播放。

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).

这种方法的用途是什么技术？他们使用什么样的调制？

推荐答案

我看到这种方法有几个问题。首先，18kHz是不听不见。许多人听不到它，尤其是随着年龄的增长，但我知道我当然可以（我经常进行听力测试，与工作有关）。此外，大多数手机的 A / D转换器都有不同的低通滤波器，许多设备，特别是较旧的Android设备（我个人看到这种情况发生），过滤低于16 kHz左右的所有设备。因此，您的应用程序无法保证可以在任何硬件上运行。 iPhone应该可以做到。

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，它可能是真的，但我肯定会排除AM。声音在音量方面几乎没有稳健性。如果我要实现类似的东西，我会选择 FSK 。我认为 PSK 会因声反射等原因而失败。困难在于您正在非常窄的带宽内进行非稳健的能量传输。我当然不怀疑它可以实现，但我没有看到这样的东西证明是可靠的。只是恕我直言，就是这样。

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：现在我想起来了，如果你有一个简单的开关可以用一个音调'不传输任何数据，只是一些短信号。

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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