A handheld wireless communications device has an adjustable volume setting. The communications device also has a downlink audio processor containing a digital audio filter. Storage in the device contains a first set of filter coefficients that configure the filter to enable the device to pass a wireless...http://www.google.de/patents/US8111842?utm_source=gb-gplus-sharePatent US8111842 - Filter adaptation based on volume setting for certification enhancement in a handheld wireless communications device
