USE OF A LINEAR FILTER TO PULSE TIMING AND AMPLITUDE FROM PPM-PAM MULTIPLEXED PULSE

The proposed PPM-PAM modulation that can change pulse timing and pulse amplitude independently has the advantage that analog and digital inf ormation can be transmitted in mixed mode. Receiving filter characteri stics used in the detection of pulse timing and amplitude are investig ated for PPM-PAM multiplexed transmission. Separation of timing and am plitude information for the isolated pulse is possible by combining th e linear filter with the signal zero crossing detector. Here error per formance is compared for the isolated pulse by using the optimum and s uboptimum filters. Then, using the effect of pulse interference at the filter output, the minimum pulse interval required for information de tection and the amount of error increase are calculated. Moreover, by calculating pulse detection error probability, the pulse detection lim it and amount of error in signal detection are investigated. As a resu lt of investigations it has been estimated that PPM-PAM multiplexed tr ansmission can be realized by using suboptimum filters because it can reduce pulse interference and attain better error performance. It has been assumed here that pulse transmission through optical fiber and ca lculations are based on Gaussian shaped pulses with white and f(2) noi se.