Patent ID: 8140106
Filing Date: 2012-03-20
Classification: H04B,H04L

Abstract:
1. A peak factor reduction device comprising: a generation section for multiplying a plurality of complex base band signals by complex exponential function signals having frequencies corresponding to the complex base band signals respectively to perform frequency conversion, and adding and combining the frequency-converted signals together to generate a multi-carrier composite signal; a peak detection section for calculating an instantaneous amplitude value of the multi-carrier composite signal and detecting a peak amplitude value brought to a maximum within a detection width; a threshold value comparison section for comparing the peak amplitude value calculated by the peak detection section and a peak factor threshold value, calculating an excessive level by which the peak amplitude value exceeds the peak factor threshold value, and outputting a signal obtained by normalizing the excessive level with the peak amplitude value; a first delayer for delaying the complex base band signals by the number of samples corresponding to a processing delay of the peak detection section and the threshold value comparison section; a first multiplier for multiplying an output of the threshold value comparison section and an output of the first delayer by each other; a filter for band-limiting an output of the first multiplier; a second delayer for delaying the multi-carrier composite signal by the number of samples corresponding to a processing delay of the peak detection section, the threshold value comparison section, and the filter; a third delayer for delaying the complex exponential function signals by the number of samples corresponding to the processing delay of the peak detection section, the threshold value comparison section, and the filter; a second multiplier for multiplying an output of the filter and an output of the third delayer by each other to perform frequency conversion; an adder for performing an additive synthesis on an output of the second multiplier to generate a peak suppression signal; and a subtractor for subtracting the peak suppression signal from an output of the second delayer.