Abstract: A method and system for remotely calibrating a headset telephone with a reliable, accurate and easy to use user interface is provided. This method makes use of the remote programmability of advanced telephone headsets and DTMF signal encoding and permits the customer-user to instigate the calibration procedure with an ordinary telephone call. The invention provides the means by which the optimum settings can be transmitted to the headset, loaded and stored in the headset, thereby improving the audio quality of telephone headsets by providing adjustment steps for such audio qualities as microphone gain (transmit level), speaker gain, background noise and echo cancellation, filter functions and diagnostics. This method also provides audio feedback to a customer service representative performing the calibration to insure that the commands and adjustments were properly received.

Abstract: A method and system for reducing background noise during a telephone call. When a caller begins dialing a telephone number, the system receives an ambient noise level measured near the caller's telephone. The system then computes an inverse noise waveform, which corresponds to the received ambient noise level. The inverse noise waveform is then transmitted along the same telephone line used by the completed call. The inverse noise waveform reduces the ambient background noise from the caller's location for the duration of the telephone call.

Abstract: Amplifier arrangement comprising :

Abstract: A noise suppression system implemented in communication system provides an improved level of quality during severe signal-to-noise ratio (SNR) conditions. The noise suppression system, inter alia, incorporates a frequency domain comb-filtering (289) technique which supplements a traditional spectral noise suppression method. The invention includes a real cepstrum generator (285) for an input signal (285) G(k) to produce a likely voiced speech pitch lag component and converting a result to frequency domain to obtain a comb-filter function (290) C(k), applying input signal (291) G(k) to comb-filter function (290) C(k), and equalizing the energies of the corresponding pre and post filtered subbands, to produce a signal (293) G″(k) to be used for noise suppression. This prevents high frequency components from being unnecessarily attenuated, thereby reducing muffling effects of prior art comb-filters.

Abstract: A dynamic voice operated filtering system for aircraft applications includes an input limiter, an expander, an output limiter and a user control. The input limiter receives an input signal representing a mixed voice and noise signal and filters the input signal. The input limiter outputs an attenuated version of the input signal (INL) to the expander. The input limiter attenuates the input signal so that the signal INL received by the expander remains within the expander's dynamic range. The expander outputs a signal INX, which represents an expanded version of signal INL. The signal INX has an amplitude that is a function of the amplitude of signal INL. The expander is configured to attenuate signal INL to serve as signal INX when the signal INL has a relatively low amplitude and amplifies signal INL to serve as the signal INX when the signal INL has a relatively high amplitude. The output limiter then receives the signal INX and, in response, filters the signal INX.