Measurement and analysis To investigate the tillage and load characteristics for each type of rotavators, the speed and torque of the PTO shaft, rotavating depth and width, actual work speed of tractor, pulverizing ratio and inversion ratio of tilled soils were measured. Then the actual field capacity (the rotavating area per unit time), the PTO power, and flow of tilled soil (the volume of tilled soil per unit time) were calculated from the measured data (Nam et al, 2012). The sampling frequency of the data acquisition system was 600 Hz, which is lager more than 10 times compared to other possible noise source’s frequency, and also from