Patent ID: 7269398
Filing Date: 2007-09-11
Classification: H03G

Abstract:
1. An automatic gain control circuit for a receive apparatus for a mobile object which automatically controls the gain of a variable gain amplifier amplifying a received signal from an antenna installed in the mobile object and outputting the amplified signal to the receive apparatus, the circuit comprising: an intensity detector that detects an intensity of the received signal; a comparator that compares the detected intensity with first and second threshold voltages; and a controller that outputs a control signal for adjusting the gain to the variable gain amplifier based on the comparing results of the comparator so that the gain of the variable gain amplifier has a hysteresis with respect to the intensity of the received signal, wherein the second threshold voltage is greater than the first threshold voltage; a gain G wherein the controller, based on the comparing results of the comparator, outputs the control signal to the variable gain amplifier to increase the gain from the gain G