Siemens Aktiengesellschaft

Gerhard Krauss

Reinhard Kern

Helmut Schlosser

Dieter K Busch

Friedrich Harless

A hearing aid circuit has an output stage which is connectable via an earphone and a battery to a circuit that has an adjustable limiting means for electrically limiting the maximum acoustic output level of the hearing aid. The limiting means is electronically designed such that a reduction in the maximally obtainable acoustic output level of the earphone in the zero position of the limitation is avoided. At least one first controllable semiconductor is operated with an adjustable component part as a current-traversed switch given a deactivated electronic limiting, and which can be operated as a current-traversed, variable resistor in the circuit given activated electronic limiting.

Hearing aid circuit having an output stage with a limiting means

A hearing aid has a microphone, an amplifier and a receiver and at least one frequency-defining element in series with a switch connected to the amplifier. For telephone listening, the switch is closed and the frequency-defining element lowers the high frequencies in the incoming signal from the telephone receiver so that a comfortable tone results for the hearing-impaired person using the telephone. The frequency-defining element may be a part of a frequency-dependent voltage divider, a part of a frequency-dependent negative feedback circuit, or a component in a resonant circuit.

Hearing aid adaptable for telephone listening

A hearing aid with wireless remote control of at least one of its controllable functions. The microphone of the hearing aird is used as a receiving element for the control signals. Energy (such as ultrasound) which the hearing aid microphone can transform into electrical signals which are separated from the other signals in a remote control part and caused to act upon the control members is used as a control signal transmission medium. Equipping a hearing aid with a remote control according to the invention is suited in particular for miniature hearing aids and for hearing aids insertable into the ear canal.

Remote control hearing aid

An exemplary embodiment comprises an acoustic signal pickup, amplification and reproduction sections wherein the latter contains a plurality of sound sources which influence a shared sound transmission arrangement collecting the sound, influencing it upon formation of a specific transfer characteristic. Given such hearing aids, the originally set frequency characteristic should also be maintained given the maximally attainable output level. To this end, the disclosure provides two identical sound sources, proceeding from which the generated sound is supplied to the ear with specific adaptation to a particular individual hearing loss. For example, the desired transfer characteristic is achieved by establishing selected differential transmission properties for the respective acoustic channels leading from the respective sound sources to the shared passage leading to the ear. An inventively improved hearing aid is particularly suitable for employment as a hearing prothesis for hearing-impaired persons.

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Nuremberg, Germany

Gerhard Krauss