Abstract: A filter system for filtering an input signal comprises a network of Prism filters including at least one cosine Prism filter and at least one sine Prism filter. The network comprises a first branch (210) in parallel with a second branch, (220) each branch arranged to receive the input signal as an input, the first branch comprising the cosine Prism filter/s (211), the second branch comprising the sine Prism filter/s (221). The network of Prism filters is arranged to generate an output signal based on a combination of an output of the first branch with an output of the second branch. A method of designing a convolutional filter is also provided, comprising inputting a test signal into a filter system to generate an impulse response of the filter system and generating a convolutional filter based on the impulse response.

Abstract: A method of estimating characteristics of an input signal comprises inputting the input signal into a first tracker to determine a first estimate of characteristics of the input signal, and determining a normalised signal from the input signal. The normalised signal is input into a second tracker to determine a second estimate of characteristics of the input signal. At least one of the first tracker and the second tracker comprises or is derived from at least one Prism filter. Further, a method of filtering an input signal is provided. The method comprises applying a sequence of one or more filter stages to the input signal to generate respective downsampled signals. A tracker stage is applied to the output of the final filter stage to determine one or more characteristics of the input signal.

Abstract: A system for tracking selected wave parameters from a received sinusoidal wave with noise and methods for making and using the same. The method includes performing a multi-track double integral analysis of the sinusoidal wave with noise and creating time dependent outputs. These time dependent outputs may be analyzed mathematically to determine the amplitude, frequency and/or phase of the wave with reduced noise. In one embodiment, the method may employ multiple passes through double integral analysis. The method advantageously can measure output sinusoidal wave parameters with reduced noise, measurements that are close to theoretical noise reduction limits.

Abstract: A system for tracking selected wave parameters from a received sinusoidal wave with noise and methods for making and using the same. The method includes performing a multi-track double integral analysis of the sinusoidal wave with noise and creating time dependent outputs. These time dependent outputs may be analyzed mathematically to determine the amplitude, frequency and/or phase of the wave with reduced noise. In one embodiment, the method may employ multiple passes through double integral analysis. The method advantageously can measure output sinusoidal wave parameters with reduced noise, measurements that are close to theoretical noise reduction limits.