Overload distortion protection for a wideband receiver

摘要

Overload distortion protection for a wideband receiver having a wideband variable gain input amplifier followed by a frequency conversion stage followed in turn by an intermediate frequency amplifier and detector to produce a measurement value in response to a signal input to the wideband variable gain input amplifier is achieved by detecting the peak power of the signal at the output of the wideband variable gain input amplifier and comparing it with the power output from the intermediate frequency amplifier and detector. If a threshold difference is exceeded, gain control signals for the wideband variable gain input and intermediate frequency amplifiers are adjusted for optimum dynamic range. If there is no range for adjusting the gain control signals, then a warning is provided to an operator to alert that the measurement value may contain distortion. <IMAGE>