When on speaker phone with somebody the sound of their own voice that comes out is not heard by them. How can the device known not to send their own voice back to them?
This even works when you are speaking at the same time. They will hear you but will not hear themselves.
How is this done? How does this work? As I type this it begins to sound more and more dumb so ill end here. Please explain.
In: Technology
This is one of the big problems in any sort of amplification circuit (speaker phones are a good example). This problem is called feedback. Any time you have amplifiers, it has a tendency for the output to “feed back” into the input, get amplified and so on. This results in an unstable system, if you’ve ever heard the screech from the speakers of a badly set up concert stage, this is feedback gone wrong.
Now, feedback is useful if controlled and this is what engineers design for in many situations. But it can be difficult to manage and this is almost an entire branch of study in engineering – that of control systems.
In modern digital speakerphones, there is software in the phones designed to eliminate the sound coming from the microphone to be amplified back to the speaker. This is sometimes called echo cancellation. It doesn’t happen “naturally”, this HAS to be designed in for the speakerphone to work effectively. What essentially happens is that the phone “remembers” what came into the input and removes this signal before sending it to the speaker. This gives the effect that the person talking does not hear themselves amplified back to them on their speaker.
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