| 摘要 |
PURPOSE:To attain an automatic correction for the carrier wave level of an input part and to obtain a fixed carrier wave level by providing a carrier wave level detecting circuit at the input part of a carrier wave distributor and feeding back the detection output of said detecting circuit as a control signal of an automatic gain control amplifier provided in a carrier wave generator. CONSTITUTION:A carrier wave generator 1 is connected to a carrier wave distributor 5 via a cable4, and an automatic gain control amplifier 2' is provided to the generator 1. A carrier level detecting circuit 12 is connected to an input terminal 6 of the distributor 5. A DC cut-off capacitor 11 is connected in parallel to the circuit 12, and a distributor circuit 7 is connected to the circuit 12. The level of the carrier wave signal sent from the generator 1 is detected by the circuit 12 and applied to the circuit 7. While the level of the carrier wave detected by the circuit 12 is fed back to the amplifier 2' of the generator 1 via the capacitor 11 and a cable 4' in the form of a control signal. Then the gain of the amplifier 2' is controlled by the fed-back control signal. Thus the level of a carrier wave can be kept at a fixed level. |
