US 5,515,445 A · Long-time balancing of omni microphones

Abstract

The long term average broad band gains of a plurality of individual signal channels, associated with a corresponding plurality of microphone elements, are electronically and dynamically adapted to one another. This is realized by periodically and dynamically processing the signals from the individual microphone elements. More specifically, the processing is such that the long term average broad band gain of the signal channels of the individual microphone elements is dynamically adjusted, an energy estimate of each microphone signal channel is averaged over the long term and the difference in energy between the signal channels is used to readjust the long term average broad band gain of the microphone signal channels to minimize those differences. In one embodiment, the adjustment is realized by obtaining an estimate of the energy of the adjusted signal in each microphone signal channel, obtaining the differences between the energy estimates and averaging the difference over the long term to obtain a gain differential correction factor which is used to readjust the long term broad band gain of at least one of the microphone signal channels to minimize the gain difference between the microphone signal channels. In another embodiment, a long term estimate of the energy in each microphone signal channel is obtained. A ratio of the energy estimates is obtained and used to adjust the long term average broad band gain of at least one of the microphone signal channels to equalize the gain in the microphone signal channels.

Claims5

Dependent claims

Apparatus for use with a plurality of microphone elements comprising:

means for generating a representation of a gain correction factor between signal channels associated with at least one pair of the plurality of microphone elements including means for obtaining an energy estimate in each signal channel associated with said at least one pair of microphone elements, means for algebraically subtracting said energy estimates to generate a difference value, means for determining the sign of the difference value and means for integrating the sign of the difference value to generate said representation of a gain correction factor;
and
means responsive to said representation of a gain correction factor for adjusting the long term average broad band gain of at least one of said signal channels, wherein the long term average broad band gains of said signal channels associated with said at least one pair of microphone elements are substantially matched to one another.

Dependencies are inferred from the claim text.

Long-time balancing of omni microphones

Life of this patent

Long-time balancing of omni microphones

Life of this patent

Abstract

Claims5