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Médico y químico, interesado en mineralogía y alquimia
| WOLFSON STEREO CODEC EXPANDS AUDIO APPLICATIONS FOR MOBILE PHONES AND
Edinburgh, UK - Wolfson Microelectronics plc has introduced a stereo
audio CODEC for multimedia mobile phones and similar applications integrating high-quality audio performance and
enhanced mixing capabilities, with low-power consumption.
The WM8983 enables flexible new usage modes for mobile
phones. These include initiating normal mobile phone functions while continuing to listen to MP3 or FM radio, as
well as audio playback during calls. Other modes include karaoke during voice calls, with full mixing capability
for headphone playback as well as recording in I2S format.
The Wolfson WM8983 high-resolution
stereo audio CODEC includes a dedicated input and output audio mixer with audio loopback for hi-fi recording, 2
microphone amplifiers, and output drivers for speaker, headphones and differential or stereo line outputs. This
eliminates separate speaker and headphone amplifiers, enabling a lower component count and a reduced footprint
implementation. The high-output BTL speaker driver is capable of driving 1 Watt into 8 ohm BTL speaker, while the
headphone driver supports “capless” operation enabling further space and cost savings.
mixed-signal technology also enables digital signal processing on-chip, enabling new mobile devices to add
innovative features exploiting hi-fi quality audio. By integrating a 5-band equalizer, 3D audio enhancement,
automatic level control and record limiter, the on-chip DSP is able to reduce the MIPS demand on the device’s main
multimedia processor, for enhanced performance and lower overall power consumption.
features enable a mobile phone to play MP3 music or MPEG4 movies with only the multimedia processor and audio CODEC
turned on, achieving power savings which can lead to longer battery life. The WM8983 digital audio interface can
operate in master or slave mode, while an integrated PLL supports flexible clocking schemes. A-law and µ-law
companding are fully supported.
A digital wind noise filter is also implemented, as well as an
IIR filter that is programmable as a notch filter. This enables fixed frequency noise reduction for improved voice
and audio performance. There is also additional power-up and power circuitry to reduce audible pops and clicks.
Digital to analogue converter (DAC) performance is 98 dB SNR and –84 dB THD, while performance of
the analogue to digital converter (ADC) is 95 dB SNR and –84 dB THD. The WM8983 operates at analogue supply voltages
from 2.5V to 3.3V, although the digital core can operate at voltages down to 1.71V to save power. Speaker supplies
can operate up to 5V for increased speaker output power. Additional power management control enables individual
sections of the chip to be powered down under software control, providing further options for designers to optimise
battery life in the end product.
Jueves, 01 Septiembre, 2005 - 10:14