Patent ID: 7856205

Claim:
An electronic communication device for converting a polyphonic note-based audio object to a Pulse Code Modulated (PCM) stream having a plurality of sample points, said polyphonic note-based audio object containing at least two notes which overlap in at least some time interval, comprising: a memory containing said polyphonic note-based audio object and a lookup table containing trigonometric function evaluations, said polyphonic note-based audio object containing note frequency information for each note; a conversion module for converting said polyphonic note-based audio object to said Pulse Code Modulated (PCM) stream; a processor for reading said memory and executing said conversion module, said conversion module including computer executable instructions for generating a PCM value for each sample point based upon each note frequency information and said trigonometric function evaluations; a phone application for establishing a voice call service over a wireless link, wherein said phone application launches said conversion module on notification of an incoming call request, and wherein said polyphonic note-based audio object comprises a ringtone; and a speaker, including a speaker driver, for receiving said PCM stream and outputting corresponding audio, wherein said computer executable instructions include instructions for selecting an entry from said look-up table based upon each note frequency information, a sampling frequency, and a sample point number, and wherein said instructions for selecting include instructions for determining a step size within the look-up table based upon a ratio between said note frequency information and said sampling frequency.