Square-root Nyquist FIR filter synthesis for QAM modems
Vyacheslav V. Shyshkin, A.N. Venetsanopoulos · International Journal of Circuit Theory and Applications · 2000
An optimal joint method for digital FIR filters synthesis used in PSK and QAM modulators and demodulators is proposed. It is based on the criterion of demodulation energy loss minimization (bit-error rate minimization). The analysis of energy loss of demodulation is developed and the objective function for energy loss minimization is obtained. The synthesis is carried out for fixed filter lengths, signal-to-noise ratio at the input of demodulator, carrier spacing between adjacent channels, and relative powers between considered and adjacent channels. This method does not require the introduction of any other weighting coefficients or functions for synthesis. Copyright © 2000 John Wiley & Sons, Ltd.