Patent ID: 6695477
Filing Date: 2004-02-24
Classification: G11C,H04R

Abstract:
A portable stereo audio signal reproducing apparatus, comprising:a user removable, exchangeable semiconductor memory unit storing digitized and high-efficiency compression encoded stereo audio data including music data portions, wherein the stereo audio data is compressed such that plural frequency bands have broader bandwidth for progressively higher frequencies taking human auditory characteristics into consideration; a decoder receiving the digitized and high-efficiency encoded stereo audio data stored in the user removable, exchangeable semiconductor memory unit for decoding the received audio data by performing an operation that is an inversion of the high-efficiency compression used to encode the audio data; a digital/analog converter for converting output signals from the decoder into analog signals; a headphone unit having left and right driver units for receiving the analog signals from the digital/analog converter and converting the analog signals from the digital/analog converter into acoustic sounds to be heard by a user of the apparatus; a portable housing separate from the headphone unit adapted to be carried by the user and containing the user removable, exchangeable semiconductor memory unit, the decoder, and the digital/analog converter; and an input unit including a plurality of user operated keys and a volume dial mounted on an outer surface of the portable housing, wherein one of said music data portions is read out from said plurality of memory chips and fed to said decoder in response to operation of one of said keys of said input unit; and flexible connecting cable for electrically connecting the portable housing to the headphone unit, wherein the analog signals from the digital/analog converter are supplied to the left and right driver units through the connecting cable.