| 摘要 |
PURPOSE:To reduce power loss and to attain small size by selecting whether a resistor or a series circuit comprising a resistor and a diode is used as a feedback circuit for a negative feedback amplifier with a switch. CONSTITUTION:Feedback is implemented through a feedback resistor R2 in the region where diodes D1, D2 are conductive and a deflection current as shown in solid lines in figure is a sawtooth deflection current T slightly larger than a usual deflection current N. The gain of a negative feedback amplifier is very high in the region where the diode D1, D2 are nonconductive and the deflection current T has a steep gradient as shown in figure. Then the scanning line interval is equal to that at usual picture display at the surrounding part of a screen of a CRT and coarse in the middle of the screen. Thus, the scanning line state is easily confirmed by using the middle part where the scanning lien interval is coarse. |
