AUTOMATIC BEAM OPTIMIZATION DEVICE FOR IMAGE ANALYZER TUBE, WITH DIODE GUN, AND TELEVISION CAMERA COMPRISING SUCH A DEVICE

摘要

P AUTOMATIC BEAM OPTIMIZATION DEVICE FOR IMAGE ANALYZER TUBE, WITH DIODE GUN, THE DIODE 2 GUN, 3 EMITTING AN ELECTRON BEAM FOR RECHARGING A PHOTOCONDUCTIVE TARGET 6, COMPRISING: / P P -An R, 19, 16 DAMPING DEVICE SERVING THE INTENSITY I OF THE CATHODE CURRENT TO A SETPOINT VALUE; / P P - AN ADJUSTABLE GENERATOR G PROVIDING A FIRST CONSTANT SETTING VALUE, CORRESPONDING TO THE CURRENT OF BEAM NEEDED AT TARGET LEVEL 6 TO RECHARGE IT WHEN THE ILLUMINATION IS EQUAL TO TWICE THE NOMINAL ILLUMINATION; / P P - A DEVICE P, 17 PROVIDING A SECOND SET VALUE THAT IS A FUNCTION OF THE VALUE V OF THE VIDEO SIGNAL SUPPLIED BY TARGET 6; / P P - A THRESHOLD SWITCHING DEVICE 18 PROVIDING TO THE DEVICE: THE FIRST SET VALUE, WHEN THE VALUE OF THE VIDEO SIGNAL PROVIDED BY THE TARGET 6 IS LESS THAN A VALUE OF FIXED THRESHOLD; OR THE SECOND SET VALUE, WHERE THE VALUE OF THIS VIDEO SIGNAL IS HIGHER THAN THE VALUE OF THRESHOLD V; THRESHOLD VALUE CORRESPONDING TO ILLUMINANCE EQUAL TO TWO TIMES NOMINAL ILLUMINATION. / P P APPLICATION TO TELEVISION CAMERAS. / P