| 摘要 |
PURPOSE:To obtain a frequency discriminator which is MOSIC-implemented, has simple circuit constitution, and eliminates the need for an external element such as a reactance element by providing a capacitor, MOSFET, and changeover switch. CONSTITUTION:The capacitor 1 with capacity C, MOSFET3, and changeover switch circuit 5 are provided. The changeover switch 5 receives an FM signal Sf to alternate the 1st and the 2nd states repeatedly at a frequency equal to or proportional to the frequency of the signal; the capacitor 1 is connected to a DC power source 2 in the 1st stage and to the source S of the MOSFET3 in the 2nd state. The gate of the MOSFET3 is biased to a fixed value by the DC power source 4. Further, the absolute value ¦V2-VGST¦ of the difference between the gate bias value V2 and gate-drain threshold value VGST of the MOSFET3 is set larger than the absolute value ¦V1¦ of the voltage V1 of the DC power source. |
