Abstract: A composite sound dampening structure includes a first base layer of sound dampening material extending around and against an inside surface of a container and a second wedge layer of sound dampening material attached to an inside surface of the first base layer. The composite sound dampening structure provides improved acoustic dampening in relative small sound chambers. An audio test system generates a composite audio signal of multiple different audio signals that are combined together using linear superposition. The composite audio signal allows a device to be simultaneously tested with multiple different audio frequencies.

Abstract: A composite sound dampening structure includes a first base layer of sound dampening material extending around and against an inside surface of a container and a second wedge layer of sound dampening material attached to an inside surface of the first base layer. The composite sound dampening structure provides improved acoustic dampening in relative small sound chambers. An audio test system generates a composite audio signal of multiple different audio signals that are combined together using linear superposition. The composite audio signal allows a device to be simultaneously tested with multiple different audio frequencies.

Abstract: A composite sound dampening structure includes a first base layer of sound dampening material extending around and against an inside surface of a container and a second wedge layer of sound dampening material attached to an inside surface of the first base layer. The composite sound dampening structure provides improved acoustic dampening in relative small sound chambers. An audio test system generates a composite audio signal of multiple different audio signals that are combined together using linear superposition. The composite audio signal allows a device to be simultaneously tested with multiple different audio frequencies.

Abstract: A method and apparatus for testing hearing aids under condition of actual use where a microprocessor is programmed to generate a warbled pure tone and analyses of the signal as processed by the device. The generated signal and a amplified signal by the hearing aid are analyzed by use of a digital Fourier transform (DFT) to arrive at the transfer function of the device in an setting approximating the environment of use and independent of extrinsic noise.

Abstract: An automatic testing system for electric nerve stimulator units is described wherein a digital computer controller utilizing programmable read only memory is used to control testing transcutaneous electrical nerve stimulator (TENS) units, such tests being conducted by sensing the output pulses from the stimulator under test and processing the output pulse signal information by circuit means under the control of the computer resulting in digital readouts of the peak output voltage, width and rate of the output pulses of the stimulator. The load impedance and quantity of delivered pulse charge for a patient can also be determined as digital readouts and indications of the pulse polarity and/or bipolarity is displayed.