There is provided a honeycomb filter obtained by bonding, into one piece, a plurality of honeycomb segments comprising partition walls having filtering function, and a number of through-holes divided from each other by the partition walls and extending in an axial direction. The apparatus includes a produce conveyer formed by a plurality of elastic bands trained around four traverse rollers. In an exemplary embodiment, a correction table is used to form a corrected control variable that affects one modulation point only of the multi-point modulation circuit. These aspects of the deep channel serve to reduce noise and allow the transistor to operate in a more repeatable and predictable manner, among other things.