[Milsurplus] OT: Microphone point source.

[Robert Nickels]

On 7/23/2013 9:39 PM, Ralph Cameron wrote:
> Each earpiece has two microphones that are about as small as you can ge
Hi Ralph,

Yes, those are MEMS microphones of the type I referenced.   It's getting 
very common to create microphone arrays like your hearing aids have, 
since DSP can do amazing things to enhance the sound. Analog processing 
is increasingly being integrated onto the same silicon die rather than 
combining a microstructure microphone with a conventional ASIC.   And 
example is Akustica which was a start-up out of Carnegie-Mellon 
University that was acquired by Bosch Group a few years ago.   They 
offer both analog and digital microphones, where a delta-sigma converter 
is integrated in CMOS just microns away from the element itself, which 
not only reduces noise and EMI susceptability, but multiple digital 
microphones can be multiplexed into a controller, with all the A/D right 
on a single CMOS chip. Silicon MEMS microphones have been growing by 
double-digits annualy are a $400 million industry today that will double 
by 2017 as this technology nears 100% penetration of all mobile phones, 
cameras, and virtually any consumer device application that accepts 
sound input.

73, Bob W9RAN