A protective mounting for a microchip on a suspension is provided by locating the microchip in an opening in the load beam extending from the edge rail side through to the slider side and attaching the microchip there to a flexible circuit conductor extending on the slider side. The RFID interrogator produces continuous wave unmodulated signals selected from frequencies comprising a predetermined frequency band. The slits of the blocking member include two rows aligned in a channel direction of the detector elements, and two rows staggered in the channel direction, thereby to obtain a CT image with improved spatial resolution. Since bus length is essentially shortened at such time, the cache memory can be accessed stably at high speed. The circuit also includes a digital phase-frequency detector for detecting an on-going phase-frequency difference between an input timing reference and an output of the divider and a digital loop filter for filtering the output of the phase-frequency detector to provide the rational number that controls the frequency of the numerically-controlled analog oscillator. A sensor for sensing movement of the engagement wheel is provided and a control system is coupled to the sensor for receiving information about positioning and movement of the engagement wheel, and is also coupled to the actuator for controlling force to the engagement wheel.