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FILTER ADAPTATION BASED ON VOLUME SETTING FOR CERTIFICATION ENHANCEMENT IN A HANDHELD WIRELESS COMMUNICATIONS DEVICE

  • US 20090252350A1
  • Filed: 01/21/2009
  • Published: 10/08/2009
  • Est. Priority Date: 04/04/2008
  • Status: Active Grant
First Claim
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1. A handheld wireless communications device having an adjustable volume setting, comprising:

  • a speaker;

    storage to store a current, user-selected volume setting for driving the speaker;

    a downlink audio processor having a chain of digital signal processing, dsp, components to process a downlink audio signal that is to then drive the speaker, said chain of dsp components include a first digital filter and a second digital filter,the first digital filter to perform equalization upon the downlink audio signal unaffected by the stored volume setting,the second digital filter adapted to have a different frequency response depending on whether the stored volume setting is low or high,wherein when the second digital filter is configured according to the low volume setting, its frequency response causes the spectral shape of sound output by the speaker, as driven by the processed downlink audio signal when the volume setting is low, to be in compliance with a wireless communications device certification mask,and wherein when the second digital filter is configured according to the high volume setting, its frequency response causes the spectral shape of sound output by the speaker, as driven by the processed downlink audio signal when the volume setting is high, to not be in compliance with the wireless communications device certification mask.

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