COMPLEX CONDITION DETERMINATION UNIT, TRANSMISSION DEVICE, COMPLEX CONDITION DETERMINATION METHOD

摘要

Disclosed is a complex condition determination unit which, to solve the problem of making it possible to change a modulation scheme adapted to rapid changes in line status, is provided with; an error-pulse switching determination means which outputs, as error-pulse determination information indicating whether an accumulated value of the number of error pulses accumulated over a predetermined period is equal to or greater than a predetermined error-pulse threshold value, the error pulses indicating whether an error exists in a received signal; a CNR (carrier-wave power to signal power ratio) modulation scheme determination means which outputs, as CNR determination information, a modulation scheme determined in accordance with a predetermined CNR threshold value and CNR information indicating the CNR of the received signal; an RSL (receive signal level) modulation scheme determination means which outputs, as RSL determination information, a modulation scheme determined in accordance with a predetermined RSL threshold value and RSL information indicating the RSL of the received signal; and a complex modulation scheme determination means which determines the modulation scheme used in order to modulate the transmission source of the received signal, in accordance with the error-pulse determination information, the CNR determination information, the RSL determination information, and received modulation scheme information indicating the modulation scheme of the received signal.