Peak envelope delivery or PEP is the average power of onc ecomplete RF cycle at the peak of the singal envelope. It is important to note that it IS NOT the power at the peak of an RF cycle during a peak of the signal's envelope.
PEP is used as it is a convient way to portray the max power of an amplitude modulated signal.
To calculate PEP, you need to know the Impedance and RMS. You can also calcuate it using the Peak Envelope Power (PEV), or the peak amplitude of one side band, or the Peak to Peak voltage (Vp-p). Vp-p is found by doubling the PEV, or taking the max voltage of both sidebands.
PEP is euqal to the average power if an amplitude-modulated signal is not modulated. This is the case when modulation is removed from an Modulation#AM signal, or with Modulation#CW keying. Because Modulation#FM signals are constant power, the PEP is always equal to average power for FM signals. In other words, if an average reading Wattmeter reads 1060W output when CW keying, then your PEP output is also 1060W.
The way to calculate it is shown below
PEP = VRMS^2 / R
PEP = ((0.707 * Vp-p) / 2)^2 / R
PEP = (PEV * 0.707)^2 / R
Where R is the loads Impedance. For example,
Peak envelope voltage (PEV) is 50V across a 50ohm load. PEP is
PEP = (50 * 0.707)^2 / 50
PEP = 25W
A 50ohm load is dissipating a 1200W PEP, the RMS voltage is
1200 = VRMS^2 / 50
60000 = VRMS^2
244.948 = VRMS