Patent ID: 8045659

Claim:
An OFDM receiver for receiving and demodulating an orthogonal frequency division multiplexing (OFDM) signal, comprising: variable gain amplifier means for controlling a signal level of an intermediate frequency signal that is obtained from a reception signal by frequency-conversion; and an automatic gain controller circuit controlling a gain of the variable gain amplifier means; wherein the automatic gain controller circuit includes clip detection means for comparing a clip number threshold value with a detected number of transient clips in which a signal level of the intermediate frequency signal exceeds a parameter clip level, so as to detect a period where the detected number exceeds the clip number threshold value, accumulator means for accumulating a detection output of the clip detection means, and target value decision means to which an accumulation output of the accumulator means is supplied; wherein the target value decision means includes first comparison means for comparing the accumulation output of the accumulator means with a clip threshold value to judge if a clip occurs, and second comparison means for comparing the accumulation output of the accumulator means with a non-clip threshold value to judge whether a clip does not occur; wherein a target value for automatic gain control is adaptively determined by decreasing the target value by a predetermined amount in accordance with a comparison output of the first comparison means and by increasing the target value by a predetermined amount in accordance with a comparison output of the second comparison means.