1. Field of the Invention
This invention relates in general to the field of telecommunications, and more particularly to an apparatus and method in a mobile station for automated audio recovery from unexpected behaviors.
2. Description of the Related Art
The cell phone industry is undergoing exponential growth, not only in this country, but all over the world. In fact, it is well known that the over twenty percent of the adult population in the United States do not even have a traditional landline telephone. In addition to those who do not own a conventional telephone, nearly ninety percent of the adult population owns a wireless phone.
And the usage of cell phones is increasing as well over the use of traditional landline telephone coverage. In fact, one in seven adults now uses only cell phones. Whereas in the past cell phones were used when a landline was not available or under emergency conditions, lower carrier rates, affordability of family packages, and free mobile-to-mobile or friend-to-friend promotions have fostered in significant increases in usage. It is not uncommon today to walk into any public forum or facility and notice a majority of the people there talking on their cell phones.
In fact, there is a substantial pull on cell phone developers to quickly field new models, and the competition in sales is unparalleled. Consequently, it is not uncommon for a developer to field a new model with relatively immature software and to provide software updates when significant bug fixes and feature enhancements are developed.
The audio path within a cell phone presents a significant challenge in that sound pressure waves are transmitted and received by a microphone and speaker, which provide for a conversion interface between these transducers and analog electrical signals. And the analog electrical signals are converted to/from digital signals by converters such as analog-to-digital converters (ADCs) and digital-to-analog converters (DACs). Other elements within the audio path of the cell phone operate upon the digital signals, ultimately ending up with a series of modulated signals that are transmitted over an air interface.
As one skilled in the art will appreciate, the conversion of analog electrical signals to digital signals that are representative of those analog electrical signals, and vice versa, is complex, and when dealing with analog signals corresponding to changing audio conditions, conversion between these two domains is exceedingly complicated because configuration of the conversion elements and other elements within the cell phone must dynamically adapt to the changing audio conditions. If fielded software in the cell phone is mature, then it is anticipated that audio processing in the cell phone will be problem free. But if the software is immature or in an intermediate state, a user may occasionally experience conditions where signal shift or improper configuration of the conversion elements results in overwhelming noise heard over the speaker or a complete mute of audio altogether.
Though infrequent, when abnormal audio path conditions occur, the only recourse that a user has in a present day cell phone is to power cycle the phone, which usually clears the problem conditions. However, to require a user to power cycle his/her cell phone is annoying and cumbersome.
Accordingly, what is needed is a mechanism in a cell phone that provides for automatic recovery from unexpected audio subsystem behaviors.