381 results about "Channel filter" patented technology

A method and system for tuning channel spacing for a wavelength division multiplexing (WDM) transport system includes determining a spectrum width for a channel. A bandwidth of a group of base channels covering the spectrum width for the channel is allocated to the channel. A passband of a channel filter at a center frequency of the group is adjusted to correspond to the spectrum width of the channel.

A wireless communications receiving apparatus and a method for removing interference in a wireless communication system. The apparatus removes interferences and comprises a power detector, a channelization filter, a channel filter unit having a plurality of filters (e.g., including an all-pass filter, a low-pass filter and a high-pass filter), a plurality of interference power detectors corresponding to the plurality of filters, a channel filter selection block and a multiplexer. The power detector receives a digital signal and detects its power, the channelization filter selects a signal having a predetermined channel frequency from the received digital signal; the channel filter unit has a plurality of filters each for receiving and filtering the signal output from the channelization filter; each of the plurality of interference power detectors respectively receives a stored training signal and a training signal received within an output signal of a corresponding filter among the plurality of filters and calculates a plurality of corresponding interference powers; the channel filter selection block outputs a selection signal based on the power of the first signal; the interference powers calculated from the plurality of interference power detectors and a plurality of reference values; and the multiplexer selects any one from the output signals of the plurality of filters based on the selection signal.

A new type of frequency-tunable active notch filter achieves frequency selectivity through interaction among input derived signal components that are passed through parallel signal channels in a forward-only direction. The notch filter differs from earlier channelized notch filters by using multiple, instead of just one, bandpass channels that maintain required forward signal flow in the main, passband-determining signal path without signal distortion at passband frequencies. The new approach has been experimentally verified with a hybrid-integrated three-channel filter whose 40-dB-deep band-reject notch can be continuously tuned, with the help of voltage-controlled variable-capacitance elements, from 9.5 to 10.5 GHz. A single-pole bandpass filter tunes in frequency with the help of only one variable capacitance element, yet still maintains constant passband width across the tuning span. One feature of the bandpass filter is the achievement of constant notch bandwidth across the entire frequency-tuning span of the notch filter.