Keywords:
portable electronic devices
multimedia
mono architecture
audio 3D
Portable electronic products, such as mobile phones, are integrating more and more
multimedia capabilities. This has created great interest in incorporating stereo capabilities. The
mono architecture is used for voice amplification, polyphonic ringing and in some cases hands free speakerphone capabilities. While adequate, this approach does not provide a satisfactory solution for high quality music playback.
Today, portable devices such as 3G mobile phones or portable media players can easily offer an audio 3D effect through digital processing. With such equipment, stereo headset listening is also embedded, and thus right and left signals are available out of a DAC or an FM tuner, for example. While the headset power is around 10 mW into a 32 Ω load, the main loudspeakers can easily draw to 1W into an 8kΩ load. At these power levels, the design challenge is to provide high efficiency with a clean audio signal. This is compounded since the need is to provide a stereo solution instead of a mono approach.
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votes:
Design 101
