Design of digital pre-compensation filters by H/sub /spl infin// optimization

Recently, several methods have been proposed to digitally compensate for the shortcomings of the analog reconstruction filters in IQ modulators using CPFSK input signals. While these methods have shown to be effective, they result in filters with long coefficients that are computationally demanding to implement on the DSP. In this paper, we present two new techniques for designing the digital compensation filters by means of H/sub /spl infin// optimization, for which there is ready-made functions in MATLAB. The simulation results show that these techniques are effective and lead to substantial improvement of the output envelope ripples.