A drumstick and method of making it are disclosed, wherein a rigid ring is fixed to a drumstick body. At the terminals, the monitored image signals which have been obtained by imaging subjects to be monitored corresponding to the terminals are respectively received to display the monitored image signals thus received, respectively. The threshold values of the pulse amplitudes are also varied depending on time. The first coefficients reduce the pre-cursor intersymbol interference and the second coefficients whiten the noise. Thus, the user can readily find out a user heshe wants to meet.