Structure synthesis and modeling of adaptive digital shaping filters

Abstract

The paper substantiates the method of automatic identification of the variance of random useful signals and random interference with given values of spectral-correlation characteristics, which allows determining the current estimates of the variance and their change for arbitrary random influences with unknown characteristics. It is shown that the parametric output of the adaptive digital filter can be used to automatically adjust the controller parameters in the control loop of the control system in the adaptation range of the adaptation coefficient, taking into account the bit depth of the ADC and DAC converters, which expands the scope of the proposed identification method.

Relevance. The relevance of the work lies in the possibility of synthesizing the structure and modeling of adaptive digital shaping filters.

Research methods. The main research method is the method of automatic identification of the variance of random useful signals and random interference with given values of spectral-correlation characteristics, which allows determining the current estimates of the variance and their change for arbitrary random influences with unknown characteristics.

Results. It is shown that the parametric output of the adaptive digital filter can be used to automatically adjust the controller parameters in the control loop of the control system in the adaptation range of the adaptation coefficient, taking into account the bit depth of the ADC and DAC converters, which expands the scope of the proposed identification method.

Conclusions. A method for automatic identification of the variance of random useful signals and random interference with given values of spectral-correlation characteristics has been substantiated, which allows determining current estimates of the variance and their change for arbitrary random influences with unknown characteristics. Automatic identification of the statistical parameters of random signals and interference in the forming adaptive filter allows taking into account their change in the optimal parameters of control system tuning. The formulas for calculating the optimal value of the adaptive filter constant time depending on the adaptation coefficient Kb, which characterize the assessment of the current ratio of the levels of the useful signal and the interference, are obtained. It is shown that the parametric output of the adaptive digital filter can be used to automatically adjust the controller parameters in the control loop of the control system in a limited range of changes in the amplitude and frequency characteristics of the useful signal and interference in the adaptation range of the adaptation coefficient at specified ratios or taking into account the bit depth of the ADC and DAC converters, which expands the scope of the proposed identification method. The simulation results on the software model of the adaptive digital filter (m-file of the modulation program) and the graphs of the simulation results showed a high interference suppression coefficient in the entire range of its change and a change in the interference level at the AF output depending on the input signal level. When the input noise level increases, the output noise level decreases. When the AFs are connected in series, the overall adaptation coefficient Kb*Kb*...automatically increases.