DATA COMMUNICATION DEVICE SELECTING MODULATION METHOD WITH AN APPROPRIATE THRESHOLD VALUE IN ADAPTIVE MODULATION

摘要

There is provided a digital communication device for performing data communication by selecting an appropriate modulation encoding method. Quality measurement means measures the line quality of data communication from a reception signal. Adaptive modulation control means compares the line quality measured by the quality measurement means to a threshold value obtained from the interrelationship between the line quality in a plurality of modulation encoding methods and the throughput characteristic, thereby selecting one of the modulation encoding methods. Here, the adaptive modulation control means uses as the threshold value a value of the line quality at the intersection of two curves indicating the aforementioned characteristic under a condition having no disturbance among the plurality of modulation encoding methods.