TRANSMISSION METHOD AND TRANSMITTER OF 4-LEVEL PPM SIGNAL

摘要

PROBLEM TO BE SOLVED: To reduce the impact of noise without increasing the data rate.SOLUTION: Transmission is performed using a composite signal obtained by adding a pulse train, having the same pulse width of reverse polarity as that of each PPM pulse and a predetermined amplitude, to a signal of PPM pulse train at the front position thereof. A composite signal of (b) is generated from a transmission signal, i.e. a 4-level PPM signal. This composite signal combines each slot with a pre-pulse of reverse polarity. The pre-pulse corresponding to slot 1 is slot 1', which has the same pulse width as the slot 1, a peak value equal to M times of slot 1, and a reverse polarity. Similarly, slots 2'-4' and 7', which are pre-pulses, are added to the slots 2-4 and 7. Slots 5' and 6' having a slot length of twice are added, as pre-slots, to the slots 5 and 6.