Hearing aid

A hearing aid, comprising:

• a microphone configured to collect ambient sounds;
• an A/D converter configured to convert an analog signal outputted from the microphone into a digital signal;
• a hearing aid processor configured to perform hearing aid processing on the digital signal outputted from the A/D converter;
• a D/A converter configured to convert the signal that has undergone the hearing aid processing into an analog signal;
• a receiver configured to output the analog signal outputted from the D/A converter as an acoustic signal to the surroundings;
• an alert sound producer configured to produce an alert sound according to a specific condition;
• a mixer that is provided between the hearing aid processor and the A/D converter, in which a first input is connected to the output of the A/D converter, the alert sound signal is inputted to a second input, and its own output is connected to the input of the hearing aid processor;
• and
• a controller that produces a mix ratio signal used by the mixer to combine the output signals of the A/D converter and the alert sound producer in a specific mix ratio, and that is connected to the mix ratio signal input terminal of the mixer,
• wherein the hearing aid processor has:
• a frequency analyzer configured to perform frequency analysis on the digital signal inputted to the hearing aid processor, and output the result as a frequency information signal;
• a gain adjuster configured to adjust the gain of the frequency information signal outputted from the frequency analyzer;
• a frequency combiner configured to combine the frequency information signal that has undergone gain adjustment with the gain adjuster into a time axis signal;
• a power calculator to which the frequency information signal outputted from the frequency analyzer is inputted, and that calculates a power value for the digital signal inputted to the frequency analyzer from the frequency information signal;
• and
• a gain controller to which the power value outputted from the power calculator is inputted, and that decides the gain at the gain adjuster on the basis of this power value and outputs it to the gain adjuster, and
• the gain controller has:
• a table memory configured to store a plurality of gain tables for performing hearing aid processing on ambient sounds collected by the microphone, and alert sound tables for performing hearing aid processing on the alert sound signals produced by the alert sound producer;
• a table selector configured to read from the table memory either the gain tables or the alert sound tables according to the mixing situation at the mixer;
• and
• a gain decider that decides the gain at the gain adjuster on the basis of the power value outputted from the power calculator by using the gain tables or the alert sound tables read by the table selector.