Digital microphone device with extended dynamic range

摘要

The present disclosure refers to a digital microphone device providing a single-bit Pulse Density Modulation PDM output signal. The digital microphone comprises a microphone, arranged to convert an acoustic input signal into an analog electrical signal, and a preamplifier, having a variable gain, arranged to receive the analog electrical signal and to provide an amplified analog electrical signal, depending on the variable gain. The variable gain depends on a gain control signal. The digital microphone further comprises an Analog-to-Digital Converter block, arranged to receive the amplified analog electrical signal and to convert it into a respective digital signal; and a compensation block, arranged to receive the digital signal and to perform a digital operation on such digital signal, on the basis of a compensation signal, to generate a compensated signal. Furthermore, the digital microphone comprises an Automatic Gain Controller block 25, arranged to detect the digital signal and to generate said gain control signal, on the basis of the detected digital signal. The Automatic Gain Controller block is further arranged to generate the compensation signal, on the basis of the control signal, and to provide the compensation signal to the compensation block, to compensate a variation of the digital signal resulting from the variable gain of the preamplifier. Finally, the digital microphone device comprises a conversion block, arranged to receive the compensated signal and to convert it into the single-bit PDM output signal.

主权项

1. An apparatus, comprising:
a digital microphone device configured to provide a single-bit Pulse Density Modulation (PDM) output signal the device including:
a microphone configured to convert an acoustic input signal into an analog electrical signal;a preamplifier, having a variable gain based on a gain control signal, the preamplifier being configured to receive the analog electrical signal and to provide an amplified analog electrical signal that depends on the variable gain;an Analog-to-Digital Converter, configured to receive the amplified analog electrical signal and to provide a digital signal;a compensation circuit, configured to receive the digital signal, to perform a digital operation on the digital signal, and based on a compensation signal generate a compensated signal;an Automatic Gain Controller, configured to detect the digital signal, to generate said gain control signal based on the detected digital signal, and to output the gain control signal to the preamplifier, the Automatic Gain Controller block configured to generate said compensation signal based on the gain control signal, and to provide the compensation signal to the compensation block, to compensate a variation of the digital signal resulting from the variable gain of the preamplifier; anda conversion circuit, configured to receive the compensated signal and to convert it into the single-bit PDM output signal.