Abstract: Reliable detection of a microphone failure along with corrective action are provided for a portable communication device having multiple microphones. The faulty microphone detection uses a correlation based metric between three (3) or more microphones. The approach is based on full cross correlation, including phase as well as magnitude, between unique microphone pairs for isolating a faulty microphone condition. The approach allows for the determination of precisely which microphone has failed and minimizes false triggers under windy conditions within a microphone array.

Abstract: A portable communication system (100) maintains mission critical functionality. An accessory (120) and a handset (130) are tethered and interoperate such that the accessory operates as the primary controlling device and the handset operates as a secondary device. The accessory (120) contains a main applications processor (102) that handles non-mission critical functions. The accessory further contains a mission critical processor (104) for handling mission critical functions of transmit and receive audio as well as PTT and emergency. In response to a failure of the mission critical processor (104), the mission critical functions are maintained by handing over the mission critical functions to the non-controlling device in a manner transparent to the user. The handover is triggered in response to status changes of the mission critical processor or as a result of battery depletion. Audio paths are re-routed through backup paths (146b, 148) negating reliance on processors of the accessory (120).

Abstract: A portable communication system (100) maintains mission critical functionality. An accessory (120) and a handset (130) are tethered and interoperate such that the accessory operates as the primary controlling device and the handset operates as a secondary device. The accessory (120) contains a main applications processor (102) that handles non-mission critical functions. The accessory further contains a mission critical processor (104) for handling mission critical functions of transmit and receive audio as well as PTT and emergency. In response to a failure of the mission critical processor (104), the mission critical functions are maintained by handing over the mission critical functions to the non-controlling device in a manner transparent to the user. The handover is triggered in response to status changes of the mission critical processor or as a result of battery depletion. Audio paths are re-routed through backup paths (146b, 148) negating reliance on processors of the accessory (120).

Abstract: A portable communication system (100) maintains mission critical functionality. An accessory (120) and a handset (130) are tethered and interoperate such that the accessory operates as the primary controlling device and the handset operates as a secondary device. The accessory (120) contains a main applications processor (102) that handles non-mission critical functions. The accessory further contains a mission critical processor (104) for handling mission critical functions of transmit and receive audio as well as PTT and emergency. In response to a failure of the mission critical processor (104), the mission critical functions are maintained by handing over the mission critical functions to the non-controlling device in a manner transparent to the user. The handover is triggered in response to status changes of the mission critical processor or as a result of battery depletion. Audio paths are re-routed through backup paths (146b,148) negating reliance on processors of the accessory (120).

Abstract: A text to speech system (100) uses differential voice coding (230, 416) to compress a database of digitized speech waveform segments (210). A seed waveform (535) is used to precondition each speech waveform prior to encoding which, upon encoding, provides a seeded preconditioned encoded speech token (550). The seed portion (541) may be removed and the preconditioned encoded speech token portion (542) may be stored in a database for text to speech synthesis. When speech it to be synthesized, upon requesting the appropriate speech waveform for the present sound to be produced, the seed portion is preappended to the preconditioned encoded speech token for differential decoding.

Abstract: A hands-free digital push-to-talk device (102) includes a digital background noise suppressor (302), a digital voice activity detector (304), an audio buffer (306), as well as a decision handler (308), embedded inside the device's (102) digital signal processor (222). Audio is buffered until the decision handler (308) determines that speech is present on an audio stream fed to the voice activity detector (304). The decision handler (308) makes the decision by assigning weighted values to each voice activity detector (304) determination, the weighted value varying depending on the state of the device (102) and temporal distance from the present time.