GB558933A - Improvements in impulse phase measuring systems - Google Patents

Abstract

558,933. Phase-difference measurements. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Oct. 30, 1942, No. 15292. Convention date, Oct. 31, 1941. [Class 37] An impulse phase measuring system employs negative transconductance valves for measuring the phase of an impulse voltage in relation to a reference voltage of the same frequency. A pair of pentodes T1, T2 have their suppressor grids 7, 17 connected in parallel, the anodes 9, 19 being also connected in parallel. The screen grids 5, 15 are connected through a pair of serially connected resistors 21, 23 across which is connected a voltmeter 25. The junction 27 of the resistors 21, 23 is connected to the cathodes 1, 11 through a battery 29 so that the cathode to screen grid circuits are connected in push-pull, the screen grids 5, 15 being positively biased with respect to the cathodes 1, 11. The battery 29 is also connected to the anodes 9, 19 through a resistor 31 and a condenser 33 may be connected between the anodes and cathodes. The reference voltage E1 is applied to the grids 3, 13 through a transformer 35 and resistors 41, 43, a battery 37 being connected to a central tapping on the secondary winding to maintain the grids 3, 13 negative with respect to their cathodes. The reference voltage E1 is thus applied to the grids 3, 13 in push-pull. The impulse voltage E is applied to the suppressor grids 7, 17 by an input circuit 45, a battery 47 applying a negative bias to the suppressor grids 7, 17 through a resistor 49. The voltmeter 25 indicates directly the phase relation between the impulse voltage E and the reference voltage E1. The reference voltage E1 may be sinusoidal or may have flattened peaks, in which latter case the resistors 41, 43 may be omitted.