A wristwatch worn by a user for measuring a three-lead ECG includes three electrodes placed separately on the front, either side, and back or strap thereof. The multi-gate HEMT includes a drainsource, a sourcedrain, a first depletion-mode gate, a second D-mode gate, and an enhancement-mode gate disposed between the first and second D-mode gates. A plurality of reference clock signals with a predetermined phase difference therebetween is selectively delayed while passing through the selected group of delay paths. The second spacing is provided at a periodic interval four times a size of a half pitch F of the bit line. The second strap portion has a longitudinal edge aligned with an opposite side edge of the tape relative to the first strap portion and an opposite longitudinal edge defined by another one of the lines of weakness.