Peak power suppressing circuit and communication device having the same

摘要

A peak power suppressing circuit can suppress a peak power of an IQ (In-phase and Quadrature-phase) baseband signal more assuredly. In particular, the peak power suppressing circuit performs a clipping process on an IQ baseband signal. The suppressing circuit includes a power calculation section that calculates an instantaneous power P of an IQ baseband signal, a pulse retention section that retains a cancellation pulse S that has a frequency component in a frequency band B of the IQ baseband signal and a frequency component outside the frequency band, and a clipping processing section that subtracts, from an IQ baseband signal whose instantaneous power P that has been calculated is greater than a predetermined threshold Pth, cancellation signals Ic and Qc obtained by multiplying increments ΔI and ΔQ of the IQ baseband signal from the threshold Pth by the cancellation pulse S.

主权项

1. A peak power suppressing circuit that performs a clipping process on an IQ (In-phase and Quadrature-phase) baseband signal, comprising:
a power calculation section that calculates an instantaneous power of the IQ baseband signal; a pulse retention section that retains a cancellation pulse that has a frequency component in a frequency band of the IQ baseband signal and a frequency component outside the frequency band; and a clipping processing section that subtracts, from the IQ baseband signal whose instantaneous power that has been calculated is greater than a predetermined threshold, a cancellation signal obtained by multiplying an increment of the IQ baseband signal from the threshold by the cancellation pulse, wherein the cancellation pulse is a synthesized pulse obtained by synthesizing a basic pulse which has a frequency component in the frequency band, and an auxiliary pulse which has a frequency component outside the frequency band that precipitously rises in a time period when the basic pulse peaks, the auxiliary pulse having a narrower pulse width and a lower peak level than the basic pulse.