GB717262A - Improvements in or relating to sawtooth voltage pulse generators - Google Patents

Abstract

717,262. Saw-tooth generating circuits. GENERAL ELECTRIC CO., Ltd., and GLEDHILL, G. A. March 10, 1953 [March 12, 1952], No. 6428/52. Class 40 (6) A saw-tooth generator 1, 2, 3, 4 of the Miller type has a direct current negative feedback path between anode and grid to cause a small stable anode current to flow during the quiescent period between output waves so that the output voltage step which normally occurs at the onset of the initiating pulse is avoided and the output wave amplitude is more stable with change of frequency. According to the invention the feedback path essentially includes a cathode follower 8, 9 fed from the anode of the Miller valve and diode or other unilateral conducting device 7 connected between the output of the cathode follower and the control grid of the Miller valve. A positive gating pulse applied to a diode 11 causes the diode 7 to be rendered non-conductive and the normal Miller run-down occurs. During the quiescent period between gating pulses the diode 7 is conducting and applies the desired potential to the control grid. The gating pulses may alternatively be applied through a cathode follower to the cathode of valve 9 and the two cathode followers may form cathode coupled multivibrator to generate the gating pulses. A capacitor may be connected across the feedback resistor 13 to prevent damped oscillations occurring at the end of the flyback due to the stray capacitance at the grid of valve 9, Fig. 2 (not shown). Further amplification may be included in the feedback path.