| 摘要 |
PURPOSE:To obain an optimum discrimination level for all the ranges of inputs C/N, by amplifying an automatic gain control voltage of an AGC amplifying circuit at a prescribed voltage amplifier and applying the signal to a comparison discriminating circuit through a voltage limit circuit. CONSTITUTION:An input signal including noise passes through an AGC amplifying circuit 1, a narrow band pass filter circuit 3, and a detection circuit 4 and is inputted to a comparison discrimination circuit 5. An AGC voltage control circuit 2 generates a signal to control the circuit 1 and the control signal is branched and inputted to a voltage amplifying circuit 7. The slipe and initial value of the input and output characteristics of the circuit 7 are determined with the ratio of a resistor 10 to a resistor 8 and a reference voltage to the circuit 7, and the output of the circuit 7 passes through a voltage control circuit 13 and reduced to the reference input to the circuit 5. |
