| 摘要 |
PURPOSE:To enable the circuit to exactly discriminate whether an inputted synchronizing signal is in a low frequency band or a high frequency band, and to prevent the circuit from abnormal synchronizing state being stabilized in a partial range of the acceptable synchronizing signal frequency. CONSTITUTION:In this horizontal deflection circuit for generating a horizontal oscillation pulse synchronized with inputted various horizontal synchronizing signal frequencies by horizontal oscillation means 2, 3, supplying the pulse to a horizontal output circuit 4 and executing horizontal deflection, whether a frequency of the horizontal oscillation pulse is in a low frequency band or a high frequency band is detected by a frequency discriminating circuit 6, and an output voltage of an F-V converting circuit 52 for a high frequency band for generating a DC voltage being proportional to the inputted horizontal synchronizing signal is detected. A detected output of the F-V converting circuit 52 and a discriminated output by the frequency discriminating circuit 6 are added logically by an adder circuit 8 and a switching signal is generated. By this switching signal, control of a free oscillation frequency of the horizontal oscillation circuit 3 and switching of an oscillation time constant are executed. |
