| 摘要 |
A pressure measuring apparatus comprises a phase locked loop including a variable frequency oscillator (1) and a quartz crystal oscillator (5) connected to the output of the variable frequency oscillator. A display conversion circuit is connected to the phase locked loop circuit. A display device (10) is connected to the display conversion circuit and the arrangement is such that the pressure to which the quartz oscillator is subjected is determined from the value of resistance, current or voltage of the quartz oscillator (5) at resonance. A temperature dependent device (11, 12) having a temperature characteristic opposite to that of the resistance, current or voltage of the quartz oscillator at resonance, and independent of pressure, is connected in series with the quartz oscillator (5). |
