The F0 estimation block determines the fundamental frequency of f1(t). This block is implemented as the Comb filtering on an amplitude spectrogram Sk(t)s [Unoki and Akagi1999b]. Since the number of channels in Xk(t) is finite, the estimated F0(t) takes a discrete value. In addition, the fluctuation of F0(t) has a staircase shape and the temporal differentiation of F0(t) is zero at any segment. Therefore, this paper assumes that E0,R(t)=0 in constraint (ii) of Table 1 for a segment. Let the length of the above segment be Th-Th-1, where Th is the continuous point of F0(t).