Control of a microphone
AssigneeNXP B.V.
InventorsHan Martijn SCHUURMANS, Maarten Wilhelmus Henricus Marie VAN DOMMELEN
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Abstract
A microphone circuit has a clip detection circuit which detects when an analogue to digital converter output has reached a threshold. A variable attenuator is controlled based on the clip detection circuit output. The feedback is thus based on the ADC output level, and the processing of this signal can be implemented without requiring baseband processing of the signal—it can simply be based on a state of the ADC output. An overrule function is also provided so that the clip detection AGC control can be inhibited or controlled differently.
Claims15
A microphone circuit comprising:
- a microphone;
- an analogue to digital converter at the output of the microphone;
- a clip detection circuit for detecting when the analogue to digital converter output has reached a threshold;
- a variable attenuator associated with the microphone;
- a control circuit for controlling the variable attenuator based on the clip detection circuit output thereby providing autonomic behaviour;
- and
- an overrule circuit for overruling the autonomic behaviour of the control of the variable attenuator based on clip detection.
A method of processing a microphone output signal, comprising:
- converting the analogue output signal of the microphone to digital using an analogue to digital converter;
- implementing clip detection by detecting when the analogue to digital converter output has reached a threshold;
- controlling a variable attenuator associated with the microphone based on the clip detection thereby providing autonomic behaviour;
- and
- detecting if an overrule command is present, and if present, overruling the autonomic behaviour of the control of the variable attenuator based on clip detection.
Dependencies are inferred from the claim text.