GB606170A - Improvements in and relating to pulse receiver circuits - Google Patents

Abstract

606,170. Valve relay circuits. BRITISH THOMSON-HOUSTON CO., Ltd. (General Electric Co.). March 5, 1946, No. 6849. [Class 40 (vi)] A receiver for pulses of high-frequency oscillations comprises a control device operated upon receipt of one of a train of pulses, the device being maintained in its operative condition for a pre-detennined time interval after reception of pulse and means for extending this interval on reception of a second pulse of the train. In the Figure, pulses of oscillations from aerial 10 are applied to the amplifier 12, which is broadly tuned to the frequency of the oscillations, further amplified in the stage 13 and applied to the diode rectifier 40, thus giving negative pulses at grid 43. Valve 14 comprises a triode and pentode section cross coupled and operating as a single stroke multivibrator circuit, so that on receipt of a negative pulse at grid 43 the triode which is normally conducting is cut-off and the pentode section. rendered conducting, the potential of the anode 53 falling and applying a negative pulse to the grid 60 of the normally conducting valve 15. The current flowing in the valve 15 is reduced and the relay 16 releases. Capacitor 58 which is normally charged through resistors 55 and 56 from the battery 29, loses charge on receipt of the negative pulse at grid 60 and only slowly charges up again as the time constant of the charging circuit is long. On receipt of a second pulse from aerial 10, the multivibrator circuit having returned substantially to 'its original condition, a negative pulse is again produced at grid 60 thus dispersing the charge which capacitor 58 obtained from the battery 29 and causing the relay 16 to remain in its in-operative condition. By adjustment of resistor 56 the relay 16 will remain in the in-operative condition during the whole of the time that a train of pulses is received at aerial 10. If the receiver is used for indicating radio echoes, a transmitter 17 coupled to aerial 10 is keyed from source 18 and the receiver is rendered inoperative by means of the gating circuit 19 for the duration of the period during which the transmitter is being keyed.