GB582231A - Improvements in repeaters for electric carrier wave signal pulses - Google Patents

Abstract

582,231. Pulse modulation; wireless signalling. STANDARD TELEPHONES & CABLES, Ltd. June 30, 1944, No. 12532. Convention date, July 1, 1943. [Class 40 (v)] A repeater for electric carrier wave signal pulses comprises a thermionic valve associated with a resonant circuit and with a blocking circuit for generating amplified pulses of highfrequency waves having a repetition rate close 'to that of the said signal pulses, and means for applying the said. signal pulses to the control grid of the valve for synchronizing the said amplified pulses, characterised by the provision of means for delaying the application of the said pulses to the control grid whereby each amplified pulse is generated later than the corresponding signal pulse. The Figure shows an arrangement suitable for relaying time modulated pulses of high-frequency energy. Valve 15 oscillates at a radio frequency determined by circuit LC to produce pulses in an antenna, not shown, coupled to inductance L at a repetition frequency determined by condenser 24 and resistance 25 in the grid circuit. The pulse period is made slightly longer than the longest interval between the incoming timemodulated pulses and so the oscillator locks in to the incoming pulses and radiates corresponding amplified time-modulated pulses. The width of the output pulse can be varied by altering the magnitude of condenser 24. Application of the incoming pulses to the grid 17 is delayed by the provision of an inductance 60 inserted in lead 21 between circuit LC and point 28, so that the repeated pulses are delayed for a selected interval of time. The device may be used for extending the useful range of a pulse modulation transmitter particularly over rough ground. Specification 509,820 is referred to.