A signal processing arrangement generates electrical stimulation signals to electrode contacts in an implanted cochlear implant array. An input sound signal is processed to generate band pass signals that each represent an associated band of audio frequencies. A spectrogram representative of frequency spectrum present in the input sound signal is generated. A characteristic envelope signal is produced for each band pass signal based on its amplitude. An active contour model is applied to estimate dominant frequencies present in the spectrogram, and the estimate is used to generate stimulation timing signals for the input sound signal. The electrode stimulation signals are produced for each electrode contact based on the envelope signals and the stimulation timing signals.

Frequency domain (FDTF) and time domain (TDTF) trans-filters compress in-band AWGN, demodulate input signals and have no threshold due to applied noise. Two parallel frequency selective networks with opposite amplitude vs frequency slopes are designed to remain 180 degrees out of phase over the signal band in the FDTF whereas two parallel delay networks are used in the TDTF. Output amplitudes are equal at band center and are summed producing a monotonic amplitude vs frequency characteristic going thru zero at center frequency with abrupt phase reversal. This produces the parabolic output noise density and differentiates applied signals. Absence of nonlinear circuit components and product devices prevents generation of noisenoise products, avoiding the threshold phenomenon. Exponentially modulated digital signals produce output impulses due to the slope and abrupt phase reversal. The impulses have strong fundamental frequency components and may be recovered at baseband without frequency conversion. Cascading trans-filters increases noise reduction and impulse amplitude. The trans-filter algorithm may be used separately or in conjunction with one or more hardware trans-filters.

A fuzzy entropy based noisy signal processing method and an iterative singular spectrum analysis (SSA) soft threshold de-noising method are disclosed. The method employs FuzzyEn, which is used to quantify the system complexity in chaos theory, to characterize a noise floor, which provides a more effective path for processing of noisy signal; its fuzzy entropy spectrum based iterative singular spectrum analysis soft threshold (SSA-IST) de-noising method outperforms the conventional truncated singular spectrum, wavelet transform and empirical mode decomposition de-noising approaches in de-noising performance.

The present invention relates to nonlinear signal processing, and, in particular, to adaptive nonlinear filtering of real-, complex-, and vector-valued signals utilizing analog Nonlinear Differential Limiters (NDLs), and to adaptive real-time signal conditioning, processing, analysis, quantification, comparison, and control. More generally, this invention relates to methods, processes and apparatus for real-time measuring and analysis of variables, and to generic measurement systems and processes. This invention also relates to methods and corresponding apparatus for measuring which extend to different applications and provide results other than instantaneous values of variables. The invention further relates to post-processing analysis of measured variables and to statistical analysis. The NDL-based filtering method and apparatus enable improvements in the overall properties of electronic devices including, but not limited to, improvements in performance, reduction in size, weight, cost, and power consumption, and, in particular for wireless devices, NDLs enable improvements in spectrum usage efficiency.

A communication device includes: a receiving circuit, receiving a plurality of time-domain signals; a transforming circuit, coupled to the receiving circuit, transforming the plurality of time-domain signals to a plurality of frequency-domain signals according to a time-frequency transform operation; a magnitude circuit, coupled to the transforming circuit, performing an absolute value operation on the plurality of frequency-domain signals to generate a plurality of output signals; and a selecting circuit, coupled to the magnitude circuit, selecting a maximum signal that satisfies a check condition from the plurality of output signals.

In accordance with an example, an integrated circuit includes a linear combiner having an input for receiving a signal. The linear combiner also has a plurality of operator circuits for applying weighting factors to the signal, in which a first operator circuit in the plurality of operator circuits performs a first operation on the signal using a first sub-weight of one of the weighting factors to provide a first tile output and a second operator circuit in the plurality of operator circuits performs a second operation on the signal using a second sub-weight of the one of the weighting factors to provide a second tile output. The linear combiner also has an adder having a first input coupled to receive the first tile output and the second tile outputs and providing a combined output.

Methods and apparatus are provided for adapting gain elements in digital filter chains. In one example, a digital filter chain includes a first digital filter and a second digital filter having an input coupled to an output of the first digital filter. A common gain is applied to signal samples passing between the first digital filter and the second digital filter, the common gain corresponding to a product of an output gain associated with the first digital filter and an input gain associated with the second digital filter. In another example, a digital filter includes an adjustable input gain element and an adjustable output gain element. The adjustable input gain element is configured to apply a gain value to an input signal sample, the gain value comprising a resultant difference of a bitshift configured for the digital filter and a bitwidth extension value. The adjustable output gain element is configured to apply an opposite of the gain value to an output signal sample.

A method and system for the design and implementation of an optimally factored filter is presented. Pairs of angle values are organized in pairing candidates and a threshold is defined to indicate an upper bound on the number of pairing candidates. A first pairing candidate is exchanged above the threshold with a second pairing candidate below the threshold and a matrix is generated based on the pairing candidates below the threshold. A lowest predicted total quantization cost between all pairing candidates represented within the matrix is determined and the pairing candidates that result in the lowest predicted total quantization cost are used to determine the coefficients of the filter.

A method and system for the design and implementation of an optimally factored filter is presented. Pairs of angle values are organized in pairing candidates and a threshold is defined to indicate an upper bound on the number of pairing candidates. A first pairing candidate is exchanged above the threshold with a second pairing candidate below the threshold and a matrix is generated based on the pairing candidates below the threshold. A lowest predicted total quantization cost between all pairing candidates represented within the matrix is determined and the pairing candidates that result in the lowest predicted total quantization cost are used to determine the coefficients of the filter.

Methods and apparatus are provided for adapting gain elements in digital filter chains. In one example, a digital filter chain includes a first digital filter and a second digital filter. The first digital filter includes a fixed point finite impulse response (FIR) filter and includes an output gain element. The second digital filter has an input coupled to an output of the first digital filter and includes an IIR filter. The output gain element applies a common output gain value that is based on a product of an input gain configured in association with the second digital filter and an FIR output gain that is based on a scaling factor K associated with the first digital filter.