| 摘要 |
PURPOSE: An accurate quadrature phase shifter is provided to obtain accurate quadrature phase shift and a 50% duty cycle. CONSTITUTION: An accurate quadrature phase shifter comprises a driving signal circuit for a micro-electromechanical system (MEMS) sensor. The driving signal circuit comprises an input, a phase shifting circuit, a comparator circuit, and a feedback loop. The input receives voltage signals which indicate electric charge generated by the MEMS sensor. The phase shifting circuit is electrically connected to the input and shifts the phase of the input signals at a right angle. The comparator circuit has hysteresis. An input of the comparator circuit is electrically connected to an output of the phase shifting circuit. An output of the comparator circuit is electrically connected to an output of the driving signal circuit. The feedback loop is connected from the output of the driving signal circuit to an input of the phase shifting circuit. The feedback loop self-generates oscillating signals or self-oscillating signals at the output of the driving signal circuit. [Reference numerals] (105) MEMS sensor; (120) Drive amplifier; (AA) Profit control; (BB) Select an output/a sine wave output |
