Peak to average power ratio

Hello,
Please help me to understand this term, Peak to average power ratio , with respect to a transmitter (power amplifier design) . In a system employing pi/4DQPSK modulation , 4 slot TDMA system at data rate of 36Kbps what would be the peak to average ratio.

To be specific it is required to know the peak to average ratio in a TETRA transmitter.

thank you

Hi,

peak-to-average ratio is a measure of the fluctuation of the envelope of modulated signals. It is defined as the peak power to the average power of a signal. A nonlinear device like a power amplifier distorts such kind of signals which leads to spectral regrowth (undesireable sidebands which corrupt neighbour channels) and inband distortion (increased bit error ratio).

To gain an understanding of this and other aspects of modulated carrier I recommend you download the free WinIQSim software from equipement manufacturer rohde-schwarz.
This software is used for generating I/Q waveforms for download to their sig gens.
To look at the peak/av power you can plot the CCDF graph of the defined waveform.
The dowload site is;
http://www.rohde-schwarz.com
and type in winiqsim in the search box.

TETRA pi/4DQPSK modulation has 3dB Peak-to-Average Ratio

I use CMD55 test GSM power !