Laundry treatment machine and method of operating the same

Disclosed are a laundry treatment machine and a method of operating the same. The method of operating a laundry treatment machine includes rotating (S710) a drum at a first velocity, forcibly vibrating (S730) the drum using a forced vibration generation signal (which corresponds to a resonance band frequency of the laundry treatment machine as an operation command value which in turn may correspond to a velocity within a range of 250 to 400 rpm) during a first velocity rotating section, and determining (S760) whether to accelerate or decelerate the drum after forced vibration. Further, the method comprises sensing (S740) unbalance during forcibly vibrating the drum in the first velocity rotating section and calculating (S750) information regarding laundry position within the drum based on the unbalance.