Microphone package and method for generating a microphone signal
A microphone package for providing a modified microphone signal includes a microphone and an equalizer device coupled to the microphone.
1. A microphone package, comprising:
a microphone configured to generate a microphone signal;
an analog-to-digital converter (ADC) circuit configured to receive the microphone signal or a signal associated therewith, and generate a digital microphone signal based thereon, wherein the digital microphone signal comprises a multi-bit signal;
an equalizer circuit configured to receive the digital microphone signal and alter a frequency response thereof in digital domain, resulting in a modified digital microphone signal; and
a modulator coupled to an output of the equalizer circuit and configured to convert the modified digital microphone signal from a multi-bit signal to a single bit representation of the modified digital microphone signal.
2. The microphone package of claim 1 , further comprising:
a common housing enclosing the microphone and the equalizer circuit at least partly.
3. The microphone package of claim 2 , wherein both the microphone and the equalizer circuit within the housing reside on a substrate.
4. The microphone package of claim 3 , wherein the substrate comprising a printed circuit board (PCB).
5. The microphone package of claim 3 , further comprising a sealing compound enclosing a portion of the microphone and an entirety of the equalizer circuit.
6. The microphone package of claim 3 , further comprising a sound port in the housing to enable pressure variations at a membrane of the microphone within the housing.
7. The microphone package of claim 1 , wherein the equalizer circuit altering the frequency response comprises the equalizer circuit being configured to reduce a resonant component within the frequency response of the digital microphone signal.
8. The microphone package of claim 1 , wherein the equalizer circuit comprises a digital finite impulse response (FIR) filter configured to alter the frequency response of the digital microphone signal in the digital domain.
9. The microphone package of claim 8 , wherein the FIR filter comprises a third order FIR filter configured to approximate an inverse of a resonant component of the frequency response of the digital microphone signal.
10. The microphone package of claim 9 , wherein the ADC circuit comprises a sampling frequency input configured to receive a variable sampling frequency signal, wherein the ADC circuit is configured to output the digital microphone signal at one of a plurality of different sampling frequencies.
11. The microphone package of claim 1 , further comprising an amplifier circuit coupled between the microphone and the ADC circuit, wherein the amplifier circuit is configured to receive the microphone signal and output an amplified version thereof.
12. The microphone package of claim 1 , wherein the microphone comprises a micro-electro-mechanical-system (MEMS).
13. The microphone package of claim 1 , wherein the equalizer circuit is configured to attenuate a first frequency portion of the microphone signal within an interval starting at 15 kHz and ending at 20 kHz relative to a second frequency portion starting at 1 kHz and ending at 5 kHz.
14. An audio processing device, comprising:
a microphone package configured to output a modified digital microphone signal, comprising:
a microphone configured to generate a microphone signal; and
an analog-to-digital converter (ADC) circuit configured to receive the microphone signal or a signal associated therewith, and generate a digital microphone signal based thereon, wherein the digital microphone signal comprises a multi-bit signal;
an equalizer circuit configured to receive the digital microphone signal and alter a frequency response thereof in digital domain, resulting in a modified digital microphone signal;
wherein the equalizer circuit is configured to modify the digital microphone signal such that a signal-to-noise ratio (SNR) of the modified digital microphone signal is increased; and
a modulator coupled to an output of the equalizer circuit and configured to convert the modified digital microphone signal from a multi-bit signal to a single bit representation of the modified digital microphone signal.
15. The audio processing device of claim 14 , further comprising:
a common housing enclosing the microphone, the ADC circuit and the equalizer circuit at least partly.
16. The audio processing device of claim 15 , further comprising:
a printed circuit board on which the microphone, the ADC circuit and the equalizer circuit reside.
17. The audio processing device of claim 16 , further comprising an encapsulation material partly encapsulating the microphone and entirely encapsulating the microphone within the common housing.
18. The audio processing device of claim 16 , further comprising a single supply voltage terminal on the printed circuit board, the single supply terminal configured to receive a common supply voltage for the microphone and the equalizer circuit.
19. The audio processing device of claim 14 , wherein the equalizer circuit altering the frequency response comprises the equalizer circuit being configured to reduce a resonant component within the frequency response of the digital microphone signal.
20. The audio processing device of claim 14 , wherein the equalizer circuit comprises a digital finite impulse response (FIR) filter configured to alter the frequency response of the digital microphone signal in the digital domain.
21. The audio processing device of claim 20 , wherein the FIR filter comprises a third order FIR filter configured to approximate an inverse of a resonant component of the frequency response of the digital microphone signal.
22. The audio processing device of claim 21 , wherein the ADC circuit comprises a sampling frequency input configured to receive a variable sampling frequency signal, wherein the ADC circuit is configured to output the digital microphone signal at one of a plurality of different sampling frequencies.
23. The audio processing device of claim 14 , further comprising an amplifier circuit coupled between the microphone and the ADC circuit, wherein the amplifier circuit is configured to receive the microphone signal and output an amplified version thereof.