Abstract: System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Abstract: System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Abstract: Systems and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. The system modulates the input signal by receiving the input signal by an N-point time input array and transforming the N-point time input array to the frequency domain by a discrete Fourier transform to generate an N-point input frequency array. The system replicates the N-point input frequency array to generate an M-point input frequency array where M is greater than N and utilizes a filter to generate a shaped M-point output filtered frequency array by multiplying the M-point input frequency array and the filter.

Abstract: System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Abstract: High-performance filter bank channelizers are provided. In one embodiment, a heterodyne signal shifts an input spectrum of the input signal by an offset between input and output centers, and operates at a high input sample rate. In another embodiment, the channelizer includes an input commutator receiving and commutating an input signal, an M-path polyphaser filter in communication with the commutator, and an M-path inverse discrete Fourier transform module processing outputs of the polyphaser filter, wherein the M-path polyphaser filter introduces a plurality of phase rotations in a time domain resulting in a workload reduction for a processor on which the channelizer is implemented. Still other embodiments includes a resampling channelizer, a half-band filter, and a cascaded half-band filter.

Abstract: Analysis channelizers are provided. In one embodiment, the channelizer includes an M-path filter receiving an input signal; a circular buffer in communication with the M-path filter; and an M-point inverse fast Fourier transform (IFFT) circuit in communication with the circular buffer, such that the channelizer aligns spectra of the input signal with spectral responses an odd length, non-maximally decimated filter bank by alternating sign heterodyne of the input signal. The channelizer applies an equivalency theorem to the non-maximally decimated filter bank formed by an odd length polyphaser filter. Advantageously, the M-path filter does not require on-line signal processing to obtain odd-indexed filter centers. In another embodiment, the channelizer alternates a sign heterodyne of a filter coefficient weight.

Abstract: System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Abstract: An apparatus, and related method, relates generally to viable bandwidth filtering. In such an apparatus, an analysis filter bank has path filters associated with different bandwidths and is configured for filtering and transforming an input signal having a first bandwidth into a first interleaved output. A mask is coupled to the analysis filter bank and configured for masking at least one narrowband time signal of the first interleaved output. A synthesis filter bank is coupled to the mask. The synthesis filter bank is configured for transforming and filtering the masked first interleaved output to generate a second interleaved output for constructing an output signal having a second bandwidth. The second bandwidth is different than the first bandwidth for the variable bandwidth filtering.

Abstract: A selectable bandwidth filter has an analysis filter bank and a synthesis filter bank having M paths. A masking vector is disposed between the analysis filter bank and the synthesis filter bank. The masking vector enables select ones and disables unselected ones of the M paths, so as to define an output signal bandwidth.

Abstract: Disclosed is apparatus and method to filter a signal. In such an apparatus, an outer polyphase filter is configured for receiving an input signal and for channelizing the input signal into outer filtered samples. An outer Inverse Fourier Transform block is coupled to the outer polyphase filter and configured for transforming the outer filtered samples into a coarse multi-path output. An inner polyphase filter is coupled to a path of the coarse multi-path output for receiving information therefrom and configured for generating inner filtered samples of the information obtained from the path. The inner filtered samples are for moving an edge of a passband associated with the outer filtered samples toward a center of the passband.

Abstract: Disclosed is apparatus and method to filter a signal. In such an apparatus, an outer polyphase filter is configured for receiving an input signal and for channelizing the input signal into outer filtered samples. An outer Inverse Fourier Transform block is coupled to the outer polyphase filter and configured for transforming the outer filtered samples into a coarse multi-path output. An inner polyphase filter is coupled to a path of the coarse multi-path output for receiving information therefrom and configured for generating inner filtered samples of the information obtained from the path. The inner filtered samples are for moving an edge of a passband associated with the outer filtered samples toward a center of the passband.

Abstract: An apparatus, and related method, relates generally to viable bandwidth filtering. In such an apparatus, an analysis filter bank has path filters associated with different bandwidths and is configured for filtering and transforming an input signal having a first bandwidth into a first interleaved output. A mask is coupled to the analysis filter bank and configured for masking at least one narrowband time signal of the first interleaved output. A synthesis filter bank is coupled to the mask. The synthesis filter bank is configured for transforming and filtering the masked first interleaved output to generate a second interleaved output for constructing an output signal having a second bandwidth. The second bandwidth is different than the first bandwidth for the variable bandwidth filtering.

Abstract: A fragmentation channelizer has a transmitter channelizing filter bank that fragments a continuous spectral span of a signal input into discrete spectral channels. The discrete spectral channels coincide with available bandwidth segments of a communications channel. A receiver has a receiver filter bank that inputs the discrete spectral channels after transmission over the communications channel and de-fragments the discrete spectral channels into a reconstructed continuous spectral span of the signal input so as to generate a signal output corresponding to the signal input.

Abstract: A pre-channelized spectrum analyzer utilizes a channelizer as a preprocessor for parallel-configured low-resolution spectrum analyzers so as to perform as a high resolution spectrum analyzer. The pre-channelized spectrum analyzer has a polyphase filter that channelizes a signal input and an IFFT that generates filter bank outputs derived from the channelized signal. Spectrum analyzers are in communications with the filter bank outputs so as to generate a spectral decomposition of a subset of those outputs. The spectrum analyzers each perform a window and an FFT function on a corresponding one of the filter bank subset.

Abstract: A synchronization recovery system is a digitized signal input derived from an analog front-end of a digital receiver and having a relatively wide bandwidth. An analysis channelizer decomposes the digitized signal input into time domain analysis channels each having a relatively narrow bandwidth. A synthesis channelizer recomposes the analysis channels so as to generate a digitized output signal. A multiplier array is disposed between the analysis channelizer and the synthesis channelizer so as to define a timing recovery vector responsive to a phase shift for retarding and advancing a timing clock. A phase locked loop is responsive to the synthesis channelizer digitized output signal so as to modify the timing recovery vector, which applies the phase shift to the time series output for each of the synthesis channelizer channels.

Abstract: An artifact-corrected time-interleaved analog-to-digital converter (ADC) for communications signals offers a significant increase in the available sample rate of ADCs by correcting timing and gain mismatches between ADC channels. These mismatches are corrected in the digital data section of a two-channel TI-ADC for band-pass input signals. This is a realistic communications system scenario as modern system designs lean towards having the ADC interface with the intermediate frequency (IF) signal in the analog section of a digital receiver rather than in the DC centered, analog down converted, in-phase and quadrature pair.

Abstract: A pair of M-path perfect reconstruction filter banks, one for analysis and one for synthesis avoid aliasing of channel filter band-edges by operating at an output sample rate of 2-samples per channel bandwidth. The non-maximally decimated analysis filter performs an M/2-to-1 down sample operation to obtain the 2-samples per channel output rate. The corresponding synthesis bank accepts signal samples at 2-samples per symbol and up-samples 1-to-M/2 to obtain the original and desired output sample rate matched to the input sample rate. Changes in composite system bandwidth are achieved by enabling or disabling the connection between the analysis filter bank and the corresponding synthesis filter bank.

Abstract: A digital receiver equalization system has a digitized signal input derived from an analog front-end of a digital receiver and having a relatively wide bandwidth. A synthesis channelizer decomposes the digitized signal input into a plurality of time domain synthesis channels each having a relatively narrow bandwidth. An analysis channelizer recomposes the synthesis channels after digital signal processing is performed on at least a portion of the synthesis channels so as to generate a digitized output signal. A channelizer domain defines digital signal processing between the synthesis channelizer and the analysis channelizer. A least a portion of the channelizer domain digital signal processing is a cascade of multiplier arrays, and at least one of the multiplier arrays has inputs that compensate for channel distortion.

Abstract: A fragmentation channelizer has a transmitter channelizing filter bank that fragments a continuous spectral span of a signal input into discrete spectral channels. The discrete spectral channels coincide with available bandwidth segments of a communications channel. A receiver has a receiver filter bank that inputs the discrete spectral channels after transmission over the communications channel and de-fragments the discrete spectral channels into a reconstructed continuous spectral span of the signal input so as to generate a signal output corresponding to the signal input.

Abstract: Methods, systems and other embodiments associated with pre-processing a signal for spectral analysis are presented. A system for pre-processing a digital input signal includes a digital down converter (DDC), an interpolator, and a series of down samplers. The DDC modulates the digital input signal to create a down converted signal. The interpolator re-samples the down converted signal to produce a re-sampled signal. The series of down samplers produces down sampled signals. The multiplexer selects one of the digital input signal, the down converted signal, and the down sampled signals and routes the selected signal to an output line.