| 摘要 |
PURPOSE:To prevent an S/N ratio from being deteriorated and improve a detecting accuracy by converting information on a gas density detected by a transmitter to frequency signals, further converting the frequency signals to light signals and transmitting the light signals to a receiver side. CONSTITUTION:The absolute pressure and the temperature of a gas are detected by an absolute pressure sensor 1 and a temperature sensor 2 in a transmitter A, respectively. A pressure value at a reference temperature is calculated by the detection signals of pressure and temperature in an arithmetic unit 7. The pressure value at the reference temperature corresponds to a gas density and a voltage proportional to the pressure is outputted from the arithmetic unit 7. Output voltage from the arithmetic unit 7 is further converted to frequency signals in a voltage/frequency converter 8 and light signals in accordance with the frequency signals are transmitted to a receiver B side from a light signal transmitter 9. The light signals received by a receiver B are converted to reproduced frequency signals, which are converted to analog signals corresponding to the reproduced frequency signals in an analog converter 21 to be outputted outside. Thus, an S/N ratio is increased and a detecting accuracy can be improved. |
