Abstract: Systems and methods for a line amplifier circuit are disclosed. The line amplifier circuit generally includes a first microphone transmit line, a second microphone transmit line, and a light emitting diode with a controllable variable light output. A photo-resistor cell is coupled across the first microphone transmit line and the second microphone transmit line. The photo-resistor cell is operable to attenuate gain on the first microphone transmit line and the second transmit line responsive to the controllable variable light output from the light-emitting diode.

Abstract: A wireless listening system includes a base operable to receive an electrical signal corresponding to an audio signal, including the ring of an incoming telephone call, up-convert the audio signal to an infrared signal, and transmit the infrared audio signal wirelessly therefrom, and a wireless headset operable to selectably receive either the infrared audio signal transmitted by the base, or an infrared signal corresponding to an audio signal transmitted by a public address system, down-convert the received signal back into the audio signal, and audibly reproduce the audio signal to a wearer of the headset. The system enables a hearing impaired listeners to enjoy their favorite audio programs without disturbing nearby persons with normal hearing and without missing an incoming telephone call, and is also compatible with public IR PA systems currently used to assist the hearing impaired community.

Abstract: The present invention provides a microphone apparatus. The microphone apparatus includes a housing with an outer surface and an interior chamber. A microphone element is disposed within the interior chamber. The outer surface includes a first substantially planar surface having at least one aperture leading to the interior chamber and a second substantially planar surface intersecting at an angle with the first planar surface.

Abstract: A wireless listening system includes a base operable to receive an electrical signal corresponding to an audio signal, including the ring of an incoming telephone call, up-convert the audio signal to an infrared signal, and transmit the infrared audio signal wirelessly therefrom, and a wireless headset operable to selectably receive either the infrared audio signal transmitted by the base, or an infrared signal corresponding to an audio signal transmitted by a public address system, down-convert the received signal back into the audio signal, and audibly reproduce the audio signal to a wearer of the headset. The system enables a hearing impaired listeners to enjoy their favorite audio programs without disturbing nearby persons with normal hearing and without missing an incoming telephone call, and is also compatible with public IR PA systems currently used to assist the hearing impaired community.

Abstract: The present invention provides a microphone apparatus. The microphone apparatus includes a housing with an outer surface and an interior chamber. A microphone element is disposed within the interior chamber. The outer surface includes a first substantially planar surface having at least one aperture leading to the interior chamber and a second substantially planar surface intersecting at an angle with the first planar surface.

Abstract: Duplex communication methods and systems with maximum gain limiting such as in telephone handsets and speaker phones are disclosed. The communications system such as a telephone set may generally include a digital signal processor (DSP) having a receive and transmit path in communication with a receiver and a transmitter, respectively, a volume amplifier for amplifying signals on the receive path, and a maximum gain limiter for determining a total return loss between the receive and transmit paths and for limiting a volume amplification level of the volume amplifier to a maximum depending on the total return loss. The maximum gain limiter determines the total return loss by maintaining a total loop gain for the telephone set at less than 0 dB to prevent unstable operation and howling.

Abstract: A full duplex telephone set for hearing impaired users includes a digital signal processor incorporating a pair of adaptive transversal filters to cancel line and acoustic echo feedback from the tip and ring signals of the set, and to condition and control the amount of a replacement side tone fed back to the receiver. This enables at least 50 dB of gain to be applied to the modified received signal without initiating unstable operation, or howl, in the set, and ensures that the received and side tone signals are heard by the user with equal comfort and clarity. The digital signal processor also enables additional enhancements to be made to the modified received signal that are beneficial to hearing impaired users, such as dynamic range compression, “soft” limiting, and low level emphasis within selectable frequency bands.

Abstract: A full duplex telephone set for hearing impaired users includes a digital signal processor incorporating a pair of adaptive transversal filters to cancel line and acoustic echo feedback from the tip and ring signals of the set, and to condition and control the amount of a replacement side tone fed back to the receiver. This enables at least 50 dB of gain to be applied to the modified received signal without initiating unstable operation, or howl, in the set, and ensures that the received and side tone signals are heard by the user with equal comfort and clarity. The digital signal processor also enables additional enhancements to be made to the modified received signal that are beneficial to hearing impaired users, such as dynamic range compression, “soft” limiting, and low level emphasis within selectable frequency bands.

Abstract: A motorcycle helmet formed from an impact resistant shell for covering and protecting the head of a user has audio receiver members mounted on the interior of the shell and has a microphone at one end of a boom within the helmet. The microphone is located for use by the user at the front of the helmet while the boom has an adapter on the end opposite the microphone. The microphone has conductors communicating with a connector which communicates with the electrical energy source and control cables. The adapter is receivable within a socket formed by a channel in an extension of one of the receiver housings so that the microphone and boom may be mounted totally within the helmet. The electrical power and control cables are connected to the microphone and the receivers by means of a quick-disconnect type connector and has a separate volume control for the microphone and for the receivers so that two motorcycle riders may adjust the audio system to their liking.