the output signals 164 a 164 b 168 a 168 b from the first second third and fourth flip flops 158 a 158 b 166 a 166 b respectively in response the exclusive or gate 174 generates an output signal 176 having pulses generally at times of each transition of the input signals 155 a 155 b thus the signal 176 is also referred to herein as a u201c count signal u201d the count signal 176 is received by a one shot circuit 178 monostable multivibrator that generates a pulse signal 180 having pulses each having a predetermined pulse width upon each transition of the signal 176 having a predetermined direction of transition for example in one particular embodiment the pulses within the pulse signal 180 are generated by the one shot circuit 178 upon each rising edge of the count signal 176 the pulse signal 180 provides a clocking signal to a fifth d type flip flop 184 the direction signal 172 is received at the d input of the d type flip flop 184 another exclusive or gate 188 is coupled to receive an output signal 186 from the d type flip flop 184 and to receive the pulse signal 180 in.