Abstract: A sound collecting device is provided which is designed to minimize adverse effects on an output caused by exposure of an electroacoustic transducer to the air. The device includes an electroacoustic transducer and a vibrating circuit. The transducer is exposed to the air and responsive to input of a sound wave to produce a corresponding acoustic signal. The vibrating circuit vibrates the transducer to shake foreign substances such as dust or drops of water from the transducer. In a modified form, an electromagnetic sensor is provided which measures an electromagnetic noise transmitted to the transducer and which removes the electromagnetic noise from an output of the transducer to produce a noiseless acoustic signal.

Abstract: A noninvasive method and system are provided for assessing the performance of implanted actuators of semi or fully-implantable hearing aid systems. The invention utilizes an externally positioned test measurement device to obtain measurements of the electrical impedance of an implanted actuator when driven by a test signal of predetermined characteristics. In one embodiment, the test measurement device may comprise a signal generator for generating the test signal for the actuator, a signal processing unit to compute the electrical impedance from voltage and current measurements, and a user interface to provide an output that is usable to asses the performance of the actuator. The electrical impedance is computable from the voltage and current of the signal passing through the actuator. The electrical impedance is directly related to the mechanical impedance present at the interface between the actuator and middle ear of a patient.

Abstract: Three surround sound channels are provided within the current formats of the Dolby Digital, Sony SDDS and DTS digital soundtrack systems in a manner that provides compatibility with conventional two surround channel playback in standard 5.1 channel and 7.1 channel systems while allowing the soundtrack preparer to send the same signal to all surround sound channels and preserving the ability to pan among the three matrix decoded surround sound channels in an arrangement that employs an active matrix decoder to provide the three surround sound channels.

Abstract: The invention comprises a transducer, computer hardware, and software. The computer hardware contains a waveform-input device. The transducer (such as a microphone) converts a signal (such as sound waves) into a time-varying voltage. The waveform-input device periodically samples this voltage and digitizes each sample, thereby producing an array of N numbers in the memory of the computer that represent a small snippet of the signal measured over a time interval &Dgr;tmeas. Snippets are typically measured one after the other at a repetition rate that is inversely related to &Dgr;tmeas. The software, also stored in the memory of the computer, and executed using its central processing unit, includes a spectral-analysis process that analyzes the frequency content of each snippet and produces an associated spectrum. The software also includes a novel note-analysis process that analyzes the spectrum and extracts from it the pitch and timbre of the principal musical note contained therein.

Abstract: A feedback controller, embedded in an FM audio processor, that controls the “integrated multiplex power” to the requirements of ITU-R 412 (2.51) is disclosed. This regulation specifies the maximum power, which is the same as the power produced by a sinewave modulating the carrier ±19 kHz (where ±75 kHz is 100% peak modulation). The controller applies the square of the multiplex signal to an integrator. A constant is removed from the integrator; representing the maximum power threshold. The output of the integrator is sampled periodically with a sample-and-hold circuit. A second integrator receives the output of the sample-and-hold. The output of the second integrator circuit is added to the threshold setting of a compressor, which determines the average power output of the compressor. The output of the compressor is applied through a peak controller to the input of the multiplex coder, closing a feedback loop, which controls the integrated multiplex power to a preset threshold.

Abstract: Reverberation imparting functions as are obtained by a mechanical type reverberation apparatus employing coil spring delaying elements are simulated by an electric circuit configuration. Three delay loop circuits are individually provided, each including a first and a second delay circuit and delaying and circulating an input signal to thereby simulate the propagation of vibrations through each individual coil spring. Multiplier circuits are provided to individually supplying the out puts from the first and the second delay circuit in one delay loop circuit to the input sides of the second and the first delay circuit in two other delay loop circuits after controlling the signal characteristic to thereby simulate the propagation of vibrations through the supporting plates for the coil springs.

Abstract: An audio interface is coupled to received a music signal and a microphone signal. The music signal and a volume control signal are combined in a multiplier to produce a volume adjusted music signal. In response to an input signal from a user, the volume control signal is gradually changed in predetermined increment levels. Thus, the multiplier gradually changes the audible volume in these predetermined increment levels. The resulting music and microphone signal are stored in corresponding partitions of a single memory, and thereafter provided to a mixing circuit. The mixing circuit combines signal samples read from the memory to produce four output signals each containing first and second channel samples. The resultant 8 channel samples are gated in a formatter with respective channel mute signals which, when asserted, effectively mute their corresponding channel sample.

Abstract: The system for assuring proper acoustic connection of a device under test to a test fixture generates an audible test signal external to the telephone handset-acoustic coupler interconnection to test the efficacy of the coupling of the telephone handset to the acoustic coupler of the test fixture. In particular, when the telephone handset is mounted in the acoustic coupler of the test fixture, this acoustic coupling should substantially block all audio signals that are present external to the acoustic coupler-telephone handset interconnection, from reaching the audio detector that is located in the acoustic coupler of the test fixture. Failure to substantially block the external audio signals indicates the inefficient mounting of the telephone handset in the test fixture.