| 摘要 |
A technique for generating coefficients for a digital filter. A gain control signal with a value of reference gain and a frequency control signal with a value of reference frequency are provided. A plurality of gain and/or frequency points are calculated, according to a model of the frequency/gain characteristic of a prototype analog filter, at frequencies equal to and less than a Nyquist frequency (where the Nyquist frequency is half the sampling frequency of the digital frequency) and which match corresponds to gain and/or frequency points in the corresponding digital filter characteristic. Pre-warped parameters of a model of the analogue filter are calculated from the calculating points and a transform is applied to the resulting pre-warped analogue model, thus, converting the pre-warped analog model into the digital domain. Coefficients from the transformed model are generated and applied to the filter, thereby generating the coefficients of the digital filter.
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