Introduction also sometimes known as pulse-phase modulation the amplitude and width of the pulse is kept constant in the system the position of each pulse, in relation to the position of a recurrent reference pulse, is varied by each instantaneous sampled value of the modulating wave

Cont..  often used in optical communication, such as fiber optics, in which there is little multipath way interference  used exclusively for transferring digital signals and cannot be used with analog systems  used for transferring simple data and is not effective at transferring files

 has the advantage over pulse amplitude modulation (PAM) in that it has a higher noise immunity  requiring constant transmitter power since the pulses are of constant amplitude and duration  signal and noise separation is very easy

 depending on transmitter-receiver synchronization  highly sensitive to multipath way interference

 Pulse position modulation can be used for a number of purposes, especially in RF (Radio Frequency) communications. -For example: pulse position modulation is used in remote- controlled aircraft, cars, boats, and other vehicles and is responsible for conveying the controls of a transmitter to a receiver. The position of each pulse may describe the physical direction of an analogue controller while the number of pulses may describe the number of possible commands that the device may receive.