CIRCUIT FOR SENSING THE ROTATION NUMBER OF WHEEL IN THE WIRELESS AUTOMATIC READING METER

摘要

An RPM(Revolution Per Minute) sensing circuit of a wireless remote meter reading device is provided to improve power efficiency by generating a low-frequency clock signal having a long cycle and a small pulse width to minimize the current consumed by a clock signal. An RPM sensing circuit of a wireless remote meter reading device is composed of a sensing clock generating unit(100) outputting a sensing clock by using hysteresis of an operational amplifier; a pulse signal generating unit(200) outputting a pulse signal correspondent to the change of capacitance generated between a rotating body and a fixed body of the wireless remote meter reading device by using the sensing clock input from the sensing clock generating unit; and an error correction unit(300) detecting an error existing in the pulse signal of the pulse signal generating unit by using the sensing clock input from the sensing clock generating unit and outputting error detection pulse for the pulse signal.