Abstract: Narrowband interference in a wideband RF signal is reduced by a notch filter operating at IF between down- and up-converters supplied by a local oscillator (LO) at a frequency controlled by a control circuit. The control circuit detects interference by determining power in each of a plurality of narrowband channels, also at IF via another down-converter with a controlled LO frequency, relative to power of the wideband RF signal and scaled in accordance with the wideband and narrowband bandwidths. The control circuit controls the LOs for scanning the narrowband channels to determine a channel with greatest interference and to filter out this narrowband channel with the notch filter. In the absence of interference, the notch is tuned outside the signal bandwidth.

Abstract: Systems and methods are provided for identifying frequency offsets which may for example have been introduced after a signal has been transmitted over a wireless channel. The method involves sampling a received signal having an input bandwidth to generate a respective set of samples for each of a plurality of symbol periods; filtering the sets of samples using DWPT (discrete wavelet packet transform) filters to produce a plurality of sub-sampled outputs, the sub-sampled outputs each having a respective fraction of the input bandwidth; for each of the sub-sampled outputs, performing a narrowband FFT on the sub-sampled output produced over a plurality of symbol periods to generate a respective set of frequency domain samples; processing each set of frequency domain samples to determine at least one respective frequency offset.

Abstract: Narrowband interference in a wideband RF signal is reduced by a notch filter operating at IF between down- and up-converters supplied by a local oscillator (LO) at a frequency controlled by a control circuit. The control circuit detects interference by determining power in each of a plurality of narrowband channels, also at IF via another down-converter with a controlled LO frequency, relative to power of the wideband RF signal and scaled in accordance with the wideband and narrowband bandwidths. The control circuit controls the LOs for scanning the narrowband channels to determine a channel with greatest interference and to filter out this narrowband channel with the notch filter. In the absence of interference, the notch is tuned outside the signal bandwidth.

Abstract: Systems and methods are provided for identifying frequency offsets which may for example have been introduced after a signal has been transmitted over a wireless channel. The method involves sampling a received signal having an input bandwidth to generate a respective set of samples for each of a plurality of symbol periods; filtering the sets of samples using DWPT (discrete wavelet packet transform) filters to produce a plurality of sub-sampled outputs, the sub-sampled outputs each having a respective fraction of the input bandwidth; for each of the sub-sampled outputs, performing a narrowband FFT on the sub-sampled output produced over a plurality of symbol periods to generate a respective set of frequency domain samples; processing each set of frequency domain samples to determine at least one respective frequency offset.