Abstract: A new modulation/demodulation method and apparatus are described for use with RF communication. A transmitter (1001T) modulates information onto a plurality of carrier signals transmitted simultaneously over a corresponding plurality of frequencies using cepstral modulation. A receiver (1003R) receives the plurality of carrier signals and demodulates the signals utilizing cepstral demodulation. Receiver (1003R) monitors the carrier signals and in response to predetermined conditions selects a cepstral constellation to be utilized. Receiver (1003R) provides the cepstral constellation information to a transmitter (1003T) that, in turn, transmits the cepstral constellation information to a receiver (1001R), in turn, provides the cepstral constellation information to transmitter (100T). Transmitter (1001T) utilizes the selected cepstral constellation information to modulate the next transmission of the plurality of carrier signals.

Abstract: A cellular communication network (10) and method operates at frequencies above 2 GHz and achieves widespread coverage within a cell (14) by adapting routing channels, symbol rates, and FEC coding processes (78) to current RF broadcast conditions. A portion of subscriber nodes (16) act as repeaters for a base node (12). If subscriber nodes (16) cannot directly communicate with the base node (12), their communications may be indirectly routed to the base node (12) through one or more repeating subscriber nodes (16'). If current conditions do not support a high data rate, then lower data rates are supported by selection of FEC coding processes (78). If increasingly inclusive FEC coding does not achieve a data rate supportable by current conditions, slower symbol rates may be used. Communications at slower symbol rates may utilize narrower frequency bands thus keeping wider frequency bands available for higher speed usage.

Abstract: Eyeglasses including lenses that contain liquid crystal nematic materials with variable refractive indexes. A voltage is applied across the materials to change the refractive index in accordance with a measured distance so that the lenses are always automatically focused as the operator looks at objects different distances away. The distances are measured by an infrared ranging system included in the glasses, which system changes the voltage applied to the material in accordance with changes in distance.

Abstract: A new modulation/demodulation method and apparatus are described for use with RF communication. A transmitter (1001T) modulates information onto a plurality of carrier signals transmitted simultaneously over a corresponding plurality of frequencies using cepstral modulation. A receiver (1003R) receives the plurality of carrier signals and demodulates the signals utilizing cepstral demodulation. Receiver (1003R) monitors the carrier signals and in response to predetermined conditions selects a cepstral constellation to be utilized. Receiver (1003R) provides the cepstral constellation information to a transmitter (1003T) that, in turn, transmits the cepstral constellation information to a receiver (1001R), in turn, provides the cepstral constellation information to transmitter (100T). Transmitter (1001T) utilizes the selected cepstral constellation information to modulate the next transmission of the plurality of carrier signals.