Transmitter
A transmitter processes signals to be transmitted. The transmitter reduces the peak power generated in a transmission signal, even when many peaks exist. In the transmitter, the peaks of the transmission target signals are detected, and a peak suppression coefficient for suppressing the detected peaks is generated. The levels of the transmission target signals are suppressed using the peak suppression coefficient generated.
1. A transmitter for processing signals to be transmitted, comprising:
a coefficient generating means for detecting peaks of levels of transmission target signals and for generating a peak suppression coefficient for suppressing the peaks altogether based on the peaks detected; and
a transmission target signal level suppressing means for suppressing the levels of the transmission target signals with the peak suppression coefficient generated by the coefficient generating means,
the coefficient generating means including:
a level detecting means for detecting the levels of the transmission target signals;
a threshold value outputting means for outputting a threshold value for the levels of the transmission target signals;
a peak detecting means for detecting a level, which is detected by the level detecting means and is equal to or exceeds the threshold value outputted from the threshold value outputting means, as a detected peak;
a time section detecting means for detecting a time position of a timely first peak, a time position of a timely last peak, and a highest level of the detected peak, in a predetermined time section;
a peak suppression ratio generating means for generating a predetermined peak suppression ratio on the basis of the threshold value outputted by the threshold value outputting means and the highest level detected by the time section detecting means;
a peak suppression ratio correcting means for correcting the peak suppression ratio generated by the peak suppression ratio generating means, on the basis of the time position of the timely first peak and the time position of the timely last peak detected by the time section detecting means; and
a peak suppression coefficient generating means for generating the peak suppression coefficient on the basis of a predetermined time position based on the time position of the timely first peak and the time position of the timely last peak, and the peak suppression ratio corrected by the peak suppression ratio correcting means.
2. The transmitter of claim 1 , wherein when only one peak is detected in a predetermined time section, the time position for the detected one peak is used as the time position of the timely first peak or the time position of the timely last peak.