Hearing aid having plural microphones and a microphone switching system
DCFirst Claim
1. A hearing aid apparatus comprising:
- an omnidirectional microphone for converting sound waves to electrical signals;
a directional microphone of at least the first order for converting sound waves into electrical signals, said electrical signals of said directional microphone having low, mid, and high frequency components, said low frequency components of said electrical signals of said directional microphone having a lower amplitude than said mid and high frequency components of said electrical signals of said directional microphone;
an equalization amplifier accepting said electrical signals from said directional microphone for at least partially equalizing said amplitude of said low frequency electrical signal components of said electrical signals of said directional microphone with said amplitude of said mid and high frequency electrical signal components of said electrical signals of said directional microphone, said equalization amplifier having an equalized electrical signal output;
a hearing aid amplifier for amplifying electrical signals received at an input thereof, andswitch means for switching between first and second switching states, said switch means connecting said electrical signal from said omnidirectional microphone to said input of said hearing aid amplifier when said switch means is in said first switching state, said switch means connecting said equalized electrical signal from said equalization amplifier to said input of said hearing aid amplifier when said switching means is in said second switching state.
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Accused Products
Abstract
A hearing aid apparatus is disclosed that employs both an omnidirectional microphone and at least one directional microphone of at least the first order. The electrical signals output from the directional microphone are supplied to an equalization amplifier which at least partially equalizes the amplitude of the low frequency electrical signal components of the electrical signal with the amplitude of the mid and high frequency electrical signal components of the electrical signals of the directional microphone. A switching circuit accepts the signals output from both the omnidirectional microphone and the directional microphone. The switching circuit connects the signal from the omnidirectional microphone to an input of a hearing aid amplifier when the switching circuit is in a first switching state, and connects the output of the equalization circuit to the hearing aid amplifier input when the switching circuit is in a second switching state. The switching circuit may be automatically switched in response to sensed ambient noise levels.
127 Citations
17 Claims
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1. A hearing aid apparatus comprising:
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an omnidirectional microphone for converting sound waves to electrical signals; a directional microphone of at least the first order for converting sound waves into electrical signals, said electrical signals of said directional microphone having low, mid, and high frequency components, said low frequency components of said electrical signals of said directional microphone having a lower amplitude than said mid and high frequency components of said electrical signals of said directional microphone; an equalization amplifier accepting said electrical signals from said directional microphone for at least partially equalizing said amplitude of said low frequency electrical signal components of said electrical signals of said directional microphone with said amplitude of said mid and high frequency electrical signal components of said electrical signals of said directional microphone, said equalization amplifier having an equalized electrical signal output; a hearing aid amplifier for amplifying electrical signals received at an input thereof, and switch means for switching between first and second switching states, said switch means connecting said electrical signal from said omnidirectional microphone to said input of said hearing aid amplifier when said switch means is in said first switching state, said switch means connecting said equalized electrical signal from said equalization amplifier to said input of said hearing aid amplifier when said switching means is in said second switching state. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A hearing aid apparatus comprising:
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a housing having an opening; a face plate covering said opening, said faceplate having a plurality of tubular bores formed therethrough; a first order directional gradient microphone having first and second spaced apart sound ports, sound waves received at said first and second sound ports being converted to an electrical signal output, each of said first and second sound ports disposed through one of said tubular bores in said face plate; a further first order directional gradient microphone having first and second spaced apart sound ports, sound waves received at said first and second sound ports being converted to an electrical signal output, each of said first and second sound ports disposed through one of said tubular bores in said face plate; a subtracter circuit for electrically subtracting said electrical signal of said first order directional microphone from said electrical signal of said further first order directional microphone to generate an electrical signal of a second order directional microphone said electrical signal of said second order directional microphone having low, mid, and high frequency components, said low frequency components of said electrical signal of said second order directional microphone having a lower amplitude than said mid and high frequency components of said electrical signal of said second order directional microphone; and an equalization amplifier accepting said electrical signal from said second order directional microphone for at least partially equalizing said amplitude of said low frequency electrical signal components of said electrical signal of said second order directional microphone with said amplitude of said mid and high frequency electrical signal components of said electrical signal of said second order directional microphone, said equalization amplifier having an equalized electrical signal output. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of operating a hearing aid apparatus comprising the steps of:
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providing said hearing aid apparatus with an omnidirectional microphone for converting sound waves to an electrical signal; providing said hearing aid apparatus with a directional microphone of at least a first order for converting sound waves into an electrical signal, said electrical signal of said directional microphone having low, mid, and high frequency components, said low frequency components of said electrical signals of said directional microphone having a lower amplitude than said mid and high frequency components of said electrical signals of said directional microphone; at least partially equalizing said amplitude of said low frequency electrical signal components of said electrical signal of said directional microphone with said amplitude of said mid and high frequency electrical signal components of said electrical signals of said directional microphone to generate an equalized electrical signal; and switching either said electrical signal of said omnidirectional microphone or said equalized electrical signal of said equalization amplifier to an input of a hearing aid amplifier. - View Dependent Claims (15, 16, 17)
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Specification