circuit 28 and multiple phase clock circuit 30 knife encoder 32 detects the rotation of a knife 34 and produces a ke output signal in the form of a stream of pulses each pulse indicates a single rotation of the knife each rotation corresponds to a single sheet of web material being cut the pulse repetition frequency of the ke pulses depends on the speed of the knife typically the frequency of the pulses is approximately 0 25 to 2 pulses per second a measuring wheel 36 detects the speed of travel of the web and triggers the board present circuit 38 the board present circuit generates a bp output signal to indicate that web material is being fed to knife 34 multiple phase clock 30 synchronizes the operation of the components of the dynamic production counter the clock generates a plurality of cyclic pulses in a predetermined phase relation it is preferred that the clock have thirty two parallel output lines denoted clk o clk 31 although more or less lines may be suitable as will be evident from the following description the clock generates a negative going pulse train on each of the clk o clk 31 output lines the pulse trains have the same amplitude duty cycle and pulse repetition frequency but are offset in phase see fig6 it is preferred that the pulse repetition frequency be approximately 62 5 khz and the pulse duration by 250 ns thus the pulse repetition frequency of each pulse train is much greater than the pulse repetition frequency of the ke pulses that is the pulse repetition frequency of.