Convention Paper
About A Digital RF-Condenser Microphone
AES Convention 116 · Paper 6130 · May 2004
Abstract
Digital microphones are commonly based on an LF-condenser wit an ADC in the same ousing.
However,this concept as some disadvantages,suc as t e inherent problems of LF-condenser
microp ones with respect to t e influence of umidity on sensitivity,distortion and low cut-off frequency.
Therefore,anot er approac for digital microphones is proposed,w ereby the capacity of t e microp one
capsule controls t e frequency of an LC-type generator.The resulting non-linear distortion is of second
order and similiar to those of classical microphones wit vacuum tube preamplifier.A negative
capacitance can be added to reduce the distortion.There are several ways to implement demodulation and
digitalization;simulations show that a sufficient dynamic range can be achieved by using a special kind of
sigma-delta FM discriminator.
