Each memory chip of a memory module tests a total of N data bits from X memory blocks for efficient testing and outputs NX data bits from one of the memory blocks. A voltage range applied to change the optical power of the liquid crystal lens is limited to a continuous tunable range of low aberration. The use of an ultrasonic initial investigation operates as an initial evaluation point for the subsequent microwave investigation. A drive circuit of the power transistor is coupled to the output terminal of the error amplifier. For an arrived packet the counts of the current subwindow are compared to a maximum value obtained from the counts of the sliding window and an absolute maximum value, and based on the result of the comparison, the policer module will transmit or discard the packet. The secondary battery charging device controls the charging a secondary battery, which has a protection timer that counts a first elapsed time from a start of charging.