The application disclose a sigma-delta analog-to-digital converter. Further, a signal processing control circuit 23 performs electricity-supply-start timing delay control processing in order to delay the timing of supplying electricity to the primary winding L1 in accordance with the power source voltage, to thereby maintain the magnetic flux energy accumulated in the ignition coil 13 at a substantially constant level. The handle attachment with the slider are depressable against the force from the biasing means, for relieving the engagement between the surface-s of the slider and of the guide groove. Having different classes of timers in the computer, a number of computations need to be performed to tie the different timers to each other. The transmitting window has a configured transmitting window size that indicates a maximum number of sequence numbers spanned by the transmitting window. In addition, where the plurality of depressions has a low profile and a greater density, increased strength is provided to the structure.