A digitally controlled analog filter device. The digitally controlled analog filter device includes one or more digitally controlled analog signal amplifiers. The digitally controlled analog signal amplifiers are configured to have a gain of the digitally controlled analog signal amplifiers controlled by digital signals. The digitally controlled analog filter device further includes one or more analog time delay circuits coupled to signal input nodes of the digitally controlled analog signal amplifiers. The analog time delay circuits are configured to implement an analog signal delay. The digitally controlled analog filter device further includes a digital closed loop control circuit coupled to the digitally controlled analog signal amplifiers to digitally control the gain of the digitally controlled analog signal amplifiers.

Examples provide a method and apparatus for an analog bi-quad infinite impulse response (IIR) filter. An amplifier generates a positive output signal corresponding to a received RF signal and a negative output signal. A set of selectively switchable time-delay circuits associated with a positive arm of the filter causes a predetermined delay corresponding to a desired sample frequency. A first set of configurable variable gain amplifiers amplify the positive output signal to establish a set of positive coefficients. A set of selectively switchable time-delay circuits associated with a negative arm of the filter causes a predetermined delay. A delayed negative output signal is generated which is amplified by a second set of configurable variable gain amplifiers to establish a set of negative coefficients. A set of power combiners function as sum junctions to combine the delayed positive output signals and the delayed negative output signals into a single output signal.

An adaptive radio frequency including an input, an output, at least one fixed passive inductor and at least one variable active inductor connected between the input and the output.

An adaptive logic board for a variable speed drive (VSD) of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a signal sensing circuit configured to receive an input signal from a sensor of the VSD. The signal sensing circuit includes a filter configured to condition the input signal. The filter includes a variable resistance element configured to adjust a cutoff frequency of the filter. The filter is configured to attenuate waveforms in the input signal having frequencies that exceed the cutoff frequency to generate a conditioned signal. The adaptive logic board also includes a controller configured to receive the conditioned signal and to adjust the variable resistance element to adjust the cutoff frequency of the filter based on a parameter of the HVAC&R system.

Method and apparatus for nonlinear signal processing include mitigation of outlier noise in the process of analog-to-digital conversion and adaptive real-time signal conditioning, processing, analysis, quantification, comparison, and control. Methods, processes and apparatus for real-time measuring and analysis of variables include statistical analysis and generic measurement systems and processes which are not specially adapted for any specific variables, or to one particular environment. Methods and corresponding apparatus for mitigation of electromagnetic interference, for improving properties of electronic devices, and for improving and/or enabling coexistence of a plurality of electronic devices include post-processing analysis of measured variables and post-processing statistical analysis.

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.

Various methods and devices that involve tuning filters are disclosed. A disclosed method for tuning a filter comprises trimming a center frequency of the filter. The method also comprises trimming an input signal magnitude of the filter. The method also comprises measuring a performance metric of the filter after trimming the center frequency of the filter and the input signal magnitude of the filter. The method also comprises repeating the trimming steps and the measuring step until the filter is tuned for a first physical test condition. A disclosed device that includes a filter also includes first and second trimming circuits that trim the center frequency and input signal magnitude of the filter. A disclosed system includes a motor to transfer a transmitting device from a first physical test condition to a second physical test condition relative to a proximity coupling device with a filter.

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.

An adaptive radio frequency including an input, an output, at least one fixed passive inductor and at least one variable active inductor connected between the input and the output.