| 摘要 |
PURPOSE:To make a reference oscillator unnecessary by a method wherein crystal is used as a filter in order to detect the phase difference between the output and input of the crystal filter and to measure frequency slippage. CONSTITUTION:The frequency to be measured and detected by a sensor 1 is amplified 2, and then inputted in parallel to a crystal filter 4 and an attenuator 6 via a limitter 3. The phase difference of a signal Vg that has passed through the crystal filter 4 and a capacitor 5 to a signal VR is detected by a phase difference circuit 7, with respect to the outputs Vg, VR of the crystal filter 4 and the attenuator 6, and displayed by a meter 8. |
