Abstract: Near-end crosstalk between identical discrete multi-tone modems is reduced by aligning the frames of all modems at a central office to each other, aligning the frames transmitted by subscribers' modems with the frames received by those modems, and including a cyclic prefix between the central office and the most distant subscriber to be served. By making adjacent DMT carrier frequencies be orthogonal to each other, the aforementioned modifications will reduce both Near End Cross-Talk and Leakage-Excited Cross-Talk. These benefits apply to modems at both the central office and subscriber ends of the communication path.

Abstract: A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with multiple reflecting antenna elements. The reflecting antenna elements are predeterminately positioned, and preferably aligned, with respect to each other in the direction of expected incident RF radiation. The reflecting antenna elements are sequentially pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the remaining reflecting antenna elements are in a substantially non-reflecting state, and when the second reflecting element is in a reflecting operating state, the remaining reflecting elements are in a non-reflecting state, etc. The sequential pulsing and predetermined fixed spacing between the reflector elements generates constructive interference between the reflected signals of the reflecting antenna elements which increases the power of the resulting reflected signal.

Abstract: A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with multiple reflecting antenna elements. The reflecting antenna elements are predeterminately positioned, and preferably aligned, with respect to each other in the direction of expected incident RF radiation. The reflecting antenna elements are sequentially pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the remaining reflecting antenna elements are in a substantially non-reflecting state, and when the second reflecting element is in a reflecting operating state, the remaining reflecting elements are in a non-reflecting state, etc. The sequential pulsing and predetermined fixed spacing between the reflector elements generates constructive interference between the reflected signals of the reflecting antenna elements which increases the power of the resulting reflected signal.

Abstract: A digital channelizer employs a polyphase filter element in which a shift register is used to commutate time series data to a bank of polyphase filters at the inputs of an FFT module. The filter bank and FFT module are updated at a frequency that is independent of the rate that the data is fed into the buffer and filter/FFT cycle rates of less than the ratio of the input data rate to the number of input channels may be accommodated by the shift register commutation. The output of the FFT module is interpolation filtered by inserting interpolated points between adjacent data points in the channelized output stream to increase the output frequency by an integral multiple of the update rate of the polyphase filter/FFT update rate.

Abstract: A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with two reflecting antenna elements. The second reflecting antenna element is predeterminately positioned, and preferably aligned, with respect to the first reflecting antenna element in the direction of expected incident RF radiation and is spaced from the first reflecting antenna element at a predetermined fixed distance. The first and second reflecting antenna elements are alternately pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the second reflecting antenna element is in a substantially non-reflecting state and vice versa. The alternate pulsing and predetermined fixed spacing between the first and second elements generates a known phase difference between the reflected signals of the first and second reflecting antenna elements.

Abstract: A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with two reflecting antenna elements. The second reflecting antenna element is predeterminately positioned, and preferably aligned, with respect to the first reflecting antenna element in the direction of expected incident RF radiation and is spaced from the first reflecting antenna element at a predetermined fixed distance. The first and second reflecting antenna elements are alternately pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the second reflecting antenna element is in a substantially non-reflecting state and vice versa. The alternate pulsing and predetermined fixed spacing between the first and second elements generates a known phase difference between the reflected signals of the first and second reflecting antenna elements.

Abstract: This invention reduces near-end crosstalk between identical discrete multi-tone (DMT-type) modems by introducing the following modifications to modems at a central office or a subscriber premises. The modifications include: a mechanism for aligning the frames of all modems at the central office (CO), a mechanism for aligning the frames transmitted by the subscribers' modems with the frames received by those modems, and lengthening the DMT frame to include a cyclic prefix. The cyclic prefix to a frame has been made longer than twice the maximum round-trip delay, that is, the delay between the central office and the most distant subscriber to be served. By making adjacent DMT carrier frequencies be orthogonal to each other, the aforementioned modifications will reduce both Near End Cross-Talk (NEXT) and Leakage-Excited Cross-Talk (LEXT). These benefits apply to modems at both the central office (CO) and subscriber ends of the communication path (for example, a high capacity twisted-pair wire).