AM-AM plot (input power vs output power) for power amplifier

1. How do you calculate the output power of an amplifier?
2. What is par in power amplifier?
3. What is power backoff?
4. Are cell phone PAs linear or nonlinear?

How do you calculate the output power of an amplifier?

Power = Voltage squared divided by Resistance.

With a constant sine wave input, you measure 10 volts AC on the speaker output of the amplifier. Since you know the resistance (5 ohms) and the voltage (10 volts), you can calculate the power: Power = (10 times 10) divided by 5 = 100/5 = 20 watts.

What is par in power amplifier?

Every signal has an average power. The peak to average power level, usually expressed in decibels, is the power level of the highest instantaneous power compared to the average power level. A PAR of 1, or 0 dB, means the signal is of constant power, so the peak power is equal to the average power.

What is power backoff?

Power Backoff in an amplifier is a power level below the saturation point at which the amplifier will continue to operate in the linear region even if there is a slight increase in the input power level. Usually, power amplifiers operate close to the saturation point as that is where efficiency is maximum.

Are cell phone PAs linear or nonlinear?

PAs exhibit nonlinear distortion in amplitude and phase.