This is a model of a QPSK modulation system for transmission over a bandpass channel with fc = 100 Hz and B = 30 Hz and AWGN at the receiver. SRRC fi lters with excess bandwidth α = 0.18 are employed. The receiver includes an NDA timing recovery loop followed by a DD phase recovery loop. -This is a model of a QPSK modulation system f or transmission over a bandpass channel with fc = 100 Hz and B = 30 Hz and AWGN at the receiver. SRRC