| 摘要 |
<p>A beam current control system for detecting and controlling a beam current generated by a cathode ray tube. The system comprises a video processing circuit (220) that receives a first signal, and which generates a second signal which is provided to the cathode ray tube (210). The cathode ray tube generates a beam current corresponding to the second signal. A storage element coupled between the video processing circuit and the cathode ray tube clamps the second signal at a first predetermined level, and stores an electrical charge corresponding to the video signal portion of the beam current during a first time interval. A first circuit coupled at one end to the storage element and at the other end, to the video processing circuit, is operable upon receipt of a control signal from the video processing circuit, corresponding to the synchronization signal during the first time interval, to facilitate discharge of the electrical charge into the first circuit. The first circuit generates a third signal representative of a magnitude of the electrical charge. A second circuit coupled to the first circuit is configured to provide an output signal to the video processing circuit, the output signal corresponding to a difference between the third signal and a second predetermined level, for adjusting the beam current during a following time interval.</p> |
