Pan Communications, Inc.

Masao Konomi

Noboru Yamaguchi

A remotely installed transmitter capable of clearly picking up only the voice of a person who is talking despite being installed away from the speaker's mouth and without causing feedback despite increased sensitivity, and a hands-free two-way voice terminal device using such a transmitter. In the remotely installed transmitter, a bidirectional microphone is installed at a central position of two pipes, two sound pick-up chambers are formed on both the right side and the left side of the pipes, the two sound pick-up chambers are stuffed with a sound-absorbing material, the shapes and sizes of the sound pick-up chambers are determined so that minimum voice resonance frequencies of the two sound pick-up chambers when they are not stuffed with the sound-absorbing material are both higher than the used upper-limit frequency of voice of the transmitter, and the amount of the sound-absorbing material is adjusted so that the voice frequency characteristics acquire monotonous attenuation characteristics in a voice frequency band higher than the used upper-limit frequency of voice.

Remotely installed transmitter and a hands-free two-way voice terminal device using same

A two way voice communications earset which is situated in the ear of the user and which includes a filter in an audio signal loop coupling a microphone and a speaker of the earset.

Two-way communications earset with filter

Hands-free speakerphone for automobile

An ambient noise suppression electrical circuit to be used with a voice communication terminal comprising a gain control amplifier, whose input is a microphone, and a peak-hold circuit that includes a band-pass amplifier that amplifies a specified frequency range of the output signals of the microphone, a peak detection circuit that produces signals in proportion to the peak level of the output signals of the band-pass amplifier, and a holding circuit that controls reduction of output signals of the peak detection circuit for a specified period of time. The output signal from the peak-hold circuit controls the gain of the gain control amplifier. When a microphone is located far from a mouth and is used under high ambient noise, the present invention makes it possible for the microphone to perform as if it is a microphone which is located in a quality telephone handset that cuts off ambient noise.

Ambient noise suppression circuit

A one piece two way voice communications earset which is situated in or at the ear of the user and which includes either two unidirectional microphones having their outputs combined or a single bi-directional microphone. The earset also includes a combination circuit for adding or subtracting the first and second signals output from the first and second microphones respectively.

Two-way communications earset

A one piece two way voice communications earset which is situated in or at the ear of the user and which includes either two unidirectional microphones having their outputs combined or a single bi-directional microphone.

A one-piece two-way voice communication earset is situated in or at the ear of the user and is operated hands-free. It includes either two separated microphones having their outputs combined or a single bidirectional microphone. In either case, the earset treats the user's voice as consisting of out-of-phase signals that are not canceled, but treats ambient noise, and any incidental feedback of sound from received voice signals, as consisting of signals more nearly in-phase that are canceled or greatly reduced in level. The microphones are preferably electret microphones. In addition, a logarithmic amplification circuit reduces residual ambient noise during non-speaking intervals. The earset includes a receiver coupled to a communication medium and a speaker coupled to the receiver for emitting sound from received voice signals primarily to the user's ear canal. A transmitter, a part of the earset also coupled to the communication medium and located outside the ear canal, houses the two microphones or the one bidirectional microphone.

A bone conduction microphone which fits into the ear of the user and which has means which abuts against the pinna of the ear causing a counteracting force to resiliently push the device against a wall of the ear canal nearest the back of the head, where bone conducted vibrations are detected most efficiently.

Bone conduction microphone mount

An ear microphone for an external auditory canal insertion type two-way communication earpiece. Within the casing of the earpiece a fixed electrode and a vibrating electrode are positioned in capacitive relation with each other, the vibrating electrode for detecting acceleration vibration from outside the casing in the form of bone-conducted voice sound vibration within the external auditory canal. Electrical signals transduced from picked-up voice sounds pass through an impedance conversion circuit mounted in the ear microphone.

Growing community of inventors

Tokyo, Japan

Masao Konomi