Pulse phase modulation (also pulse position modulation, pulse- position modulation English, PPM) is a modulation method of discrete-time (i.e., sampled ) signals. It is a pulse, usually a rectangular pulse, shifted relative to a constant reference clock in a position ( phase). In this phase shift of the sample is coded. The duration of the pulse is constant. The modulated signal is time - continuous and amplitude- back.
The radio remote controls in earlier related pulse - pause modulation can be regarded as differential pulse phase modulation. More recently, the PPM ultra wide band applications wins, a so-called pulse radio again important.
For the offset from the reference clock applies:
- Vmax the absolute value of the maximum amplitude.
That is, the nearer the beginning of the pulse of the reference clock is, the lower is the amplitude of the original signal, that is the sample. Conversely, the later the pulse in the reference clock is, the greater the amplitude.