Analog signal input/output system using network lines

Mikio Hasegawa, Hiroyuki Morikawa, Udana Bandara, Masugi Inoue

Research output: Contribution to journalReview article


The present invention is an instrument (specifically, an Internet speaker) that is equipped with an analog signal input terminal that converts analog input signals into digital signals and transmits the converted signals to the host computer over a network. The instrument also features an analog output terminal that receives the digital signals generated by the host computer and transmitted over a network and converts the received digital signals into analog signals for output. This architecture allows audio signals from the computer to be output to the present instrument and also permits audio signals input to the present instrument to be transferred to the host computer over the network. For the former function, output may be selectively switched between multiple Internet speakers. Furthermore, since the Internet speaker requires no dedicated circuitry, it may be installed anywhere with access to a network socket. However, there is one problem with this otherwise apparently very convenient Internet speaker. Generally, network delays are not constant, and are dependent on the volume of the information passing through the network, and so the delays may not be negligible in cases where stereo audio data are reproduced over such network lines subject to fluctuating delays. However, the present invention is equipped with a synchronous control mechanism for delay-free transmission, enabling faithful reproduction of the phase of the sound output fromboth speakers of the stereo system. Furthermore, this invention is capable of adapting immediately to any changes in the coding or reproduction method. Through such innovations, the architecture of the present instrument has been made suitable for applications that demand functions such as high-quality stereo reproduction requiring precise phase reproduction of the left and right phases, easy switchover between collective/selective transmission, and a local-area broadcasting system that allows two-way communication.

Original languageEnglish
Pages (from-to)193-194
Number of pages2
JournalJournal of the National Institute of Information and Communications Technology
Issue number1-2
Publication statusPublished - 1 Mar 2007


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