Patent ID: 11871193
Assignee: CIRRUS LOGIC INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A microphone system, comprising:
a first transducer, for generating a first acoustic signal;
a second transducer, for generating a second acoustic signal;
a high-pass filter, for receiving the first signal and generating a first filtered signal, wherein the first transducer and the second transducer have different acoustic properties;
a low-pass filter, for receiving the second signal and generating a second filtered signal;
an adder, for forming an output signal of the microphone system as a sum of the first filtered signal and the second filtered signal;
a first band-pass filter, configured to receive the first signal during a calibration mode;
a second band-pass filter, configured to receive the second signal during the calibration mode;
an adjustable gain block; and
a feedback loop;
wherein the first band-pass filter and the second band-pass filter each have pass bands that encompass a first frequency at which the high-pass filter and the low-pass filter both pass signals;
wherein the feedback loop acts during the calibration mode to determine a gain value required such that the first signal and the second signal have the same magnitude at the first frequency; and
wherein, in operation of the microphone system, said required gain value is applied to the first filtered signal and/or to the second filtered signal before it is passed to the adder.