| 主权项 |
1. A hearing aid for automatically controlling directivity, the hearing aid comprising:
a first input unit that senses a sound to thus generate a first audio signal, and amplifies the first audio signal in response to a first amplification control signal, to then output a first input signal; at least one second input unit that senses the sound to thus generate a second audio signal, and amplifies and delays the second audio signal in response to at least one second amplification control signal and at least one delay time control signal, to then output a second input signal; a subtraction unit having at least one subtractor that is configured in a multi-stage of the same number as that of the at least one second input unit, and that subtracts the second input signal output from a corresponding second input unit among the at least one second input unit from a cumulative subtraction signal output from a preceding stage, to thus output the cumulative subtraction signal; a directivity controller that receives the cumulative subtraction signal output from a last stage subtractor among the at least one subtractor, performs a filtering of the received signal to thus extract a speech sound signal, compares the maximum value of the extracted speech sound signal with a predetermined threshold value, and controls the first amplification control signal, the at least one second amplification control signal, and the at least one delay time control signal, to thus output the controlled result; and an output unit that receives and amplifies the cumulative subtraction signal output from the last stage subtractor among the at least one subtractor, wherein the directivity controller comprises:
a filter unit that receives and filters the cumulative subtraction signal, to thereby extracting the speech signal;a maximum value detector for detecting the level of the speech signal and detecting the maximum value;a threshold value setting unit that set and stores the threshold;a comparator that compares the maximum value with the threshold value, and outputs a comparison value if the maximum value is less than the threshold value;an amplification factor controller that controls the first amplification control signal and the at least one second amplification control signal, respectively, in response to the comparison value, and outputs the controller result; anda delay time controller that controls the at least one delay time control signal, respectively, in response to the comparison value, and outputs the controller result, wherein the filter unit comprises:
a band-pass filter that receives the cumulative signal and performs band pass filtering; anda rectifier filter that rectifies the output signal of the band-pass filter, and outputs the speech sound signal. |
