Patent ID: 8649528

Claim:
A microphone assembly, comprising: a microphone assembly casing having a sound inlet port; a transducer for receiving acoustic waves through the sound inlet port, and for converting received acoustic waves to analog audio signals, said transducer being positioned within the microphone assembly casing; and an electronic circuit positioned within the microphone assembly casing, said electronic circuit includes a signal path defined by a cascade of, a pre-amplifier having an input and an output terminal, the input terminal being connected to the transducer so as to receive analog audio signals from the transducer, a sigma-delta modulator having an input and an output terminal, the input terminal being connected to the output terminal of the pre-amplifier so as to receive amplified analog audio signals from the pre-amplifier and to convert said amplified analog audio signals to digital audio signals, and a filter means connected between the pre-amplifier and the sigma-delta modulator, wherein, the filter means is a high pass filter, or a band pass filter including a high pass filter and a low pass filter, the microphone assembly casing is metallic, or includes a metallic layer so as to establish a Faraday cage, the pre-amplifier, the sigma-delta modulator and at least part of the filter means are integrated on a same chip to form a monolithic integrated circuit that is an application-specific integrated circuit (ASIC), and the microphone assembly is connected to a pure digital processor for further digital signal processing.