Microphone device

1. Microphone device, comprising:

a main microphone;

at least one control microphone; and

a digital signal processing unit, coupled to the main microphone and the at least one control microphone for receiving a first signal from the main microphone and for receiving a second signal from the at least one control microphone and for emitting a third signal,

said digital signal processing unit comprising

a suppression filter for receiving the first signal, for performing a noise-suppression of pop noise and for emitting the third signal, wherein the suppression filter is a high pass filter with an adjustable cut-off frequency, and

a processing unit for determining the cut-off frequency based on the second signal.

2. Microphone device, comprising:

a main microphone;

at least one control microphone; and

a digital signal processing unit, coupled to the main microphone and the at least one control microphone for receiving a first signal from the main microphone and for receiving a second signal from the at least one control microphone and for emitting a third signal,

said digital signal processing unit comprising

a suppression filter for receiving the first signal, for performing a noise-suppression of pop noise and for emitting the third signal, wherein the suppression filter is a high pass filter with an adjustable cut-off frequency, and

a processing unit for determining the cut-off frequency based on the second signal, wherein the processing unit is adapted to

receive the second signal, wherein the second signal comprises a fourth signal from a first control microphone and a fifth signal from a second control microphone;

calculate the signal power of the difference-signal between the fourth signal and the fifth signal;

calculate the signal power of the sum-signal of the fourth signal and the fifth signal; and

calculate the ratio of the difference-signal power to the sum-signal power, and

wherein the processing unit comprises a calculating unit for comparing the ratio to a maximum threshold value and for adjusting the cut-off frequency if the determined ratio exceeds the maximum threshold value.

3. Microphone device according to claim 2 , wherein the digital signal processing unit furthermore comprises:

a first filter bank for computing a first set of frequency band signals from the fourth signal;

a second filter bank for computing a second set of frequency band signals from the fifth signal,

wherein the output of the first and second filter banks are forwarded to the processing unit; and

the processing unit is adapted to calculate a set of ratios of the difference-signal power to the sum-signal power from each two elements of the first and second signal set that belong to the same frequency band;

compare each element of the set of ratios to an associated maximum threshold value; and

adjust the cut-off frequency in a way, that only those frequencies with dominant pop noise are removed.

4. Microphone device according to claim 2 ,

wherein the calculating unit is adapted to provide a lower cut-off frequency if the ratio of the difference-signal power to the sum-signal power does not exceed the maximum threshold value any more.

5. Method for suppressing pop noises in a microphone device having a main microphone, at least one control microphone and a digital signal processing unit, coupled to the main microphone and the at least one control microphone comprising the steps of:

receiving a first signal from the main microphone, receiving a second signal from the at least one control microphone and emitting a third signal;

filtering the first signal with a suppression filter to suppress pop noises and to obtain the third signal, wherein the suppression filter is a high pass filter with an adjustable cut-off frequency; and

determining the cut-off frequency based on the second signal.

6. Method for suppressing pop noises in a microphone device having a main microphone, at least one control microphone and a digital signal processing unit, coupled to the main microphone and the at least one control microphone comprising the steps of:

receiving a first signal from the main microphone, receiving a second signal from the at least one control microphone and emitting a third signal;

filtering the first signal with a suppression filter to suppress pop noises and to obtain the third signal, wherein the suppression filter is a high pass filter with an adjustable cut-off frequency; and

determining the cut-off frequency based on the second signal, wherein determining the cut-off frequency comprises the steps of:

receiving the second signal, wherein the second signal comprises a fourth signal from a first control microphone and a fifth signal from a second control microphone;

calculating the signal power of the difference-signal between the fourth signal and the fifth signal;

calculating the signal power of the sum-signal of the fourth signal and the fifth signal;

calculating the ratio of the difference-signal power to the sum-signal power;

comparing the ratio to a maximum threshold value; and

adjusting the cut-off frequency if the calculated ratio exceeds the maximum threshold value.

7. Method for operating a microphone device according to claim 6 , wherein determining the cut-off frequency furthermore comprises the steps of:

computing a first set of frequency band signals from the fourth signal, using a first filter bank;

computing a second set of frequency band signals from the fifth signal, using a second filter bank;

calculating a set of ratios of the difference-signal power to the sum-signal power from each two elements of the first and second signal set that belong to the same frequency band;

comparing each element of the set of ratios to an associated maximum threshold value; and

adjusting the cut-off frequency in a way, that only those frequencies with dominant pop noise are removed.

8. Method for operating a microphone device according to claim 6 , further comprising the step of:

providing a lower cut-off frequency is if the ratio of the difference-signal power to the sum-signal power does not exceed the maximum threshold value any more.