Digital microphones
AssigneeCirrus Logic International Semiconductor Ltd.
InventorsJohn Paul LESSO, John Laurence MELANSON
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Abstract
This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to apply a selective gain modulation to signals in the second signal path.
Claims18
A digital microphone apparatus for outputting a digital output signal at a sample rate defined by a received clock signal, the apparatus comprising:
- a band splitter configured to receive a microphone signal indicative of an output of a microphone transducer and split said microphone signal into first signal path for frequencies in a first band and a second signal path for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band;
- and
- a modulation block configured to apply a selective gain modulation to signals in the second signal path.
A digital microphone apparatus as claimed in 7 wherein the band-pass filter in the second signal path is configured so that its pass-band is variable.
A digital microphone apparatus for outputting a digital output signal at a sample rate defined by a received clock signal, the apparatus comprising:
- a band splitter configured to receive a microphone signal indicative of an output of a microphone transducer and split said microphone signal into first signal path for frequencies in a first band and a second signal path for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band;
- and
- a modulation block comprising a detector for detecting the power of any signal component in the second frequency band, a gain element in the second signal path and a gain controller for controlling a gain setting of the gain element based on the detected power.
Dependencies are inferred from the claim text.