| 摘要 |
PURPOSE:To hold a property of following changes in input frequency while removing a ripple component of an output voltage, by connecting a variable cut-off frequency low-pass filter to an output of a frequency/voltage converter. CONSTITUTION:An input of a low-pass filter 4 adapted to vary cut-off frequency according to the frequency of a pulse input is connected to an output of a frequency/voltage converter made up of a clocked logic circuit 1, an analog switch 2 and an integrator circuit 3. The output from the low-pass filter 4 is partly used as its own control voltage through a delay circuit 5. With such an arrangement, the cut-off frequency can be varied according to the frequency of the input pulse to the frequency/voltage converter and a ripple component of an output voltage of the frequency-voltage converter is removed from a low frequency input while a property of following changes in the frequency of an input is held thereby achieving a higher stability of the output. |
