Patent ID: 8055228

Claim:
A received signal strength indicator, comprising: a multi-stage amplification section including a plurality of limiters connected in series to each other and individually having variable current sources for calibrating gains; a rectification section comprising a plurality of rectifiers configured for receiving and rectifying an output of each of the plurality of limiters, and outputting a direct current corresponding to the output; a load resistor converting the direct currents output from the plurality of rectifiers into a voltage; and a gain calibration section comprising: a calibration limiter, the calibration limiter corresponding to at least one of the plurality of limiters included in the multi-stage amplification section; a calibration load unit connected to output terminals of the calibration limiter, and generating an output differential voltage whose gain is a unit gain when a predetermined input differential voltage is input to the calibration limiter; and a comparison and adjustment unit comparing the input differential voltage with the output differential voltage, and generating an adjustment current for adjusting an output of a variable current source included in the calibration limiter so that the input differential voltage becomes identical to the output differential voltage, wherein the adjustment current generated from the gain calibration section is supplied to the variable current sources of the plurality of limiters included in the multi-stage amplification section.