GB738522A - Improvements relating to magnetron pulse generators - Google Patents

Abstract

738,522. Valve circuits. METROPOLITANVICKERS ELECTRICAL CO., Ltd. April 12, 1954 [April 30, 1953], No. 12024/53. Class 40 (6). A magnetron pulse circuit comprises control apparatus which interrupts or modifies the operation of the magnetron when the rate of occurrence of pulses in undesired modes becomes excessive. In Fig. 1 the output of a magnetron is fed to a filter which selects pulses of the desired frequency. Those pulses are rectified and applied to valve V1 while the grid of valve V2 is fed with pulses directly from the pulse modulator so that when the magnetron operates in the wrong mode and the pulses do not appear at the grid of V1 the valves V1 and V2 become unbalanced and produce pulses at P. These pulses are passed via a valve V3 to valve V4 to cause capacitors C1 and C2 to charge to a voltage dependent upon the rate of occurrence of the pulses. When the rate is excessive the voltage is sufficient to render a valve V5 sufficiently conductive to operate a relay which interrupts temporarily the operation of the magnetron. The function of valves V1 and V2 may be carried out in a single valve (Fig. 2, not shown) and the determination of the rate of occurrence of the pulses from valves V1 and V2 may alternatively be effected by charging a capacitor through a diode circuit (Fig. 3, not shown). In Fig. 4 the protection is afforded by reducing the repetition frequency of the pulses from the modulator and the control voltage for this purpose is obtained from valves V7 and V8. Valve V7 is normally cut off but is rendered conductive when the absence of negative rectified pulses on the grid of a valve V6 permits the pulses from the modulator to charge a capacitor C5 to a sufficiently large positive voltage.