Audio streaming is made available throughout the
signal processing path of the
speech processor of a
cochlear implant or other
audio signal processor. Audio streaming comprises the digitally phase locked playback of a real time n-bit
digital audio stream, where n may be a large number, e.g., 8, 12, 16, 24 or 32, that emanates (unsolicited) from an operating
speech processor. A number of sample points are made available long the
processing chain of a
digital signal processor (DSP) used within the
speech processor of the
cochlear implant. Audio streaming may occur at any sample point. The
signal at a selected sample point may be selectively monitored in order to allow appropriate diagnostics to be performed. Audio streaming utilizes an auto-referencing mixed-mode
phase locked loop. Such
phase locked loop processes an asynchronous
stream of
digital audio samples that arrive at a designated location, e.g., a selected sample point, at a consistent, but unknown, average rate. Once the
stream of asynchronous audio samples are received, the average sample rate is extracted, and a local
clock is generated at the average frequency. The incoming audio streaming samples are then re-synchronized with the local
clock. in order to allow digitally phase locked playback of the audio stream.