Apple echo cancellation

Apple has today been granted five new patents by the US Patent and Trademark Office. The majority cover mundane designs: one documents a method of displaying text based on reference points such as intervals, while three others cover existing iPod accessories, namely sleeves, caps for the first-generation iPod shuffle, and the various dock inserts used to accomodate different player sizes. The iPod patents are credited to Apple CEO Steve Jobs, as well has a host of engineers.

More unique is the remaining patent, which addresses a proposed solution for echo cancellation. Echo in two-way voice communication is caused by received audio being picked up by a microphone; traditionally, this has been dealt with by suppressing the microphone's input while incoming sound is detected. More recently, noise cancellation has been used to filter out feedback, but this poses technical problems such as high processor load.

Apple solution would gauge the correlation between speaker output and microphone input, and modulate an adaptive gain for an acoustic echo canceller, using said correlation as the basis. Provided with the patent is an elaborate diagram (see below) including numerous components, such an encoder, decoder, main processor and signal analyzer. What device this technology might be used in is unknown, since Apple now has a variety of products with voice communication, including desktop computers and the iPhone.

by MacNN Staff