Patent ID: 9111548
Filing Date: 2015-08-18
Classification: G10L,H04R

Abstract:
1. A method, the method comprising: receiving first analog signals from a first microphone, converting the first analog signals into first pulse code modulation (PCM) digital data and storing the first PCM digital data in a first buffer using a first microphone internal clock; receiving a second analog signals from a second microphone according to a second microphone internal clock, converting the second analog signal into second PCM digital data and storing the second PCM digital data in a second buffer; wherein the first PCM digital data in the first buffer is not synchronized in real time with the second PCM digital data in the second buffer due to the absence of a common clock or other synchronizing signal between the first microphone and the second microphone; determining whether voice activity has occurred at a first acoustic activity detect (AAD) module based upon the first PCM digital data, and when voice activity is determined, transmitting a voice activity detect signal to an external processor, the external processor responsively providing an exterior clock signal upon receiving the voice activity detect signal; up-converting the first PCM digital data into first pulse density modulation (PDM) data and the second PCM digital data into second PDM data based upon the exterior clock signal to eliminate a lack of synchronization or time uncertainty between the first PCM data and the second PCM data; decimating the first PDM data and the second PDM data using the exterior clock signal to provide decimated output pulse code modulation (PCM) data, the decimated output PCM data including a first PCM sample and a second PCM sample, wherein each of the first PCM sample and the second PCM sample begin and end on the same bit clock edge of the exterior clock signal.