| 摘要 |
PURPOSE:To stabilize an automatic control system, and to shorten a response time for settng appropriately the amount of exposure quickly correspondig to the sudden change of the exposure at high-speed pickup time, by varying the response time of the automatic exposure control system in proportion to the speed of taking a motion picture. CONSTITUTION:In comparator 3, signal S1 of the quantity of X rays outputted from transmissive X-ray quantity detector 1 is compared with the set output from reference X-ray quantity setter 4, deviation signal S3 is supplied to pulse-width control circuit 5, and X-ray tube grid controller 6 controls the grid voltage of X-ray tube 7, thereby adjusting the X-ray pulse width. In addition, signal S3 is supplied to gate circuit 8, and signal S5 selected by gate signal S4 is sent to tube-voltage controller 9 to control the primary voltage of high-voltage generator 10, thereby adjusting the tube voltage of X-ray tube 7. By crankspeed signal S6 set by motion picture camera controller 11, shutter pulse generator 12 supplies X-ray pulse signal S7, synchronizing with the above-mentioned set speed, to control circuit 5 and also sends signal S7 to counting circuit. Signal S4 proportional to the crankspeed is supplied from circuit 13 to circuit 8 to control the generation of signal S5. |
