Patent ID: 9281792
Filing Date: 2016-03-08
CPC Classification: H03G,H04L

Claim Text:
1. A receiver comprising: a voltage control variable gain amplifier to vary a gain to amplify a reception signal according to a gain control signal; a filter circuit to filter a signal obtained by converting a frequency of an output signal from the voltage control variable gain amplifier; a demodulator to generate a digital signal based on an output signal from the filter circuit, and to generate quality voltage information indicating a quality of the digital signal; and a power detection evaluation circuit to perform evaluation processing to detect a plurality of kinds of poor reception states based on the quality voltage information in addition to at least one of a voltage value of the gain control signal, a voltage value of the output signal from the voltage control variable gain amplifier, a voltage value of the reception signal, a voltage value of the output signal from the filter circuit, and a voltage value of an intermediate node of the filter circuit, and controls the gain control signal when the power detection evaluation circuit detects one of the poor reception states so that the voltage value of the output signal from the voltage control variable gain amplifier becomes low, wherein the power detection evaluation circuit compares a difference between the voltage value of the output signal from the filter circuit and the voltage value of the intermediate node with a first threshold, calculates a reception level of an interference wave of an adjacent channel of a desired wave in the reception signal according to the comparison, and changes the voltage value of the gain control signal according to whether or not the reception level is greater than or equal to a predetermined value.