Robert Boschgmbh

Gerd-Wolfgang Gotze

Manfred Muller

Albert Eggert

Peter Wiener

Wolfgang Kopke

Rainer Maas

Hearing aid responsive to signals inside and outside of the audio

An audiometer which can be battery operated, is reliable and economical in current consumption has a digital control unit (10) which controls a LCD in matric form (11, 26). The digital control unit, in its simplest form, includes a data input stage (12) having two inputs (16, 18) receiving, respectively, input signals representative of amplitude and tone, or a spoken word, and a further input (14) which is test-person controlled, to provide a perception signal, operated by the person to be tested when the level of a certain tone, generated by a tone generator (G, 21) is perceived, or a spoken word is correctly heard. The data input stage is connected to a data bus which provides the respective data to a driver circuit (24) to drive the LCD matrix. Various accessories can be provided, such a curve generating stage (45), a memory (42), an output unit for a recorder, such as a plotter, and a separate input/output state (46) to receive, for example, stored data for comparison of an audiogram being taken of a test-person with prior, or statistically derived audiograms.

Audiometer

To provide for tuning of an oscillator circuit, a plurality of resistors are selectively connectable in the circuit. To provide for reproducible, accurate oscillation frequency in accordance with switching of a respective resistor in dependence on a digital input signal, electronic switches are respectively connected to the resistors to connect them in circuit in the oscillator to thereby eliminate variable contact resistances of mechanical switches. A digital frequency control signal is generated by placing a movable mask or pattern with openings therein between an array, for example a linear strip of light emitting diodes, and a similar strip of photo transistors, the respective energization of which is determined by openings in the diaphragm. The signals from the photo transistors are stored in a memory, typically a group of flip-flops, for application to the electronic switches controlling connection of the respective resistors in the oscillator circuit.

Audiometer with photo sensitive, digitally tunable low distortion

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Berlin, Germany

Gerd-Wolfgang Gotze