Question

Difference between inputbackoff and output backoff

Answer 1

Input Back-Off (IPBO) is the power level at the input of RF amplifier relative to input power which produces maximum output power.

Example: 
Input power level causes max. output power = -20dBm
Actual input power level = -25dBm
Input backoff(IPBO)= 5dB

Output Back-Off (OPBO) is the power level at the output of RF amplifier relative to maximum output level possible using the RF amplifier. 

EXAMPLE: 
Maximum output level = +40dBm
Measured output level of RF Amplifier = +34dBm
Output Backoff(OPBO)= 6dB