Pulse phase modulation

The Pulse Position Modulation (PPM) (English: pulse position modulation ) is a modulation of discrete-time ( sampled ) signals.

A pulse is shifted relative to a constant reference clock in terms of time, namely the phase. This phase shift symbolizes the original signal. The period and the amplitude remain the same.

The pulse-pause modulation previously used in radio remote controls is a differential pulse phase modulation.

Pulse phase modulation has recently been gaining importance again due to the ultra- broadband application of pulse radio .

The following applies to the time shift compared to the reference clock: ${\displaystyle \Delta \tau }$

${\displaystyle \Delta \tau (k)={\frac {T}{2}}{\Big (}1+{\frac {v(kT)}{v_{\text{max}}}}{\Big )}}$

It is

• v (kT) the k-th sample value for a period (of the reference clock) T and
• v _{max is} the amplitude.

The greater the amplitude of the original signal, the greater the time shift between the rising edge of the reference clock and the rising edge of the modulated signal.

literature

• Karl-Dirk Kammeyer: message transmission . 4th edition. Vieweg + Teubner, 2008, ISBN 978-3-8351-0179-1 , p. 203 f .