Improvements in or relating to relative phase responsive arrangements

Abstract

Abstract 703,189. Phase-difference measurements. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. May 20, 1952 [July 10, 1951], No. 16358/ 51. Class 37 A phase responsive arrangement comprises means for producing, from each of the waves to be compared, one pulse per cycle at a predetermined point in the cycle, a multi-vibrator circuit, means controlled by the produced pulses for controlling the operation of this circuit between its two conditions of stability, in dependence upon the phase relation between the pulses from the two waves, and means for charging a condenser at a predetermined rate in one direction or the other according to the condition of stability of the circuit. The, two waves to be compared are fed at A1, B1 to two separate channels A,' B and amplified by amplifiers A2, B2, the amplifier A2 being followed by a phase changer A3, squaring circuit A4, and differentiating circuit A5. The amplifier B2 is followed by a squaring circuit B4, and differentiating circuit B5. The outputs of the circuits A5, B5 are fed to selector circuits A6, B6 which select only the pulses of the same predetermined polarity, which are fed to the grids of the valves VA, VB of a multi-vibrator circuit having two conditions of stability, in one of which only the valve VA conducts and in the other of which only the valve VB conducts. Each pulse occurs when the wave passes through zero in 'one chosen direction only. If the pulses from channel B. occur midway between those from channel A the periods during which the two conditions of stability exist will be equal, but for all other relative phases between the inputs A1, B1 these periods will be unequal. Connected between the anode circuits of the valves VA, VB is a condenser CAB, which is charged in one direction or the other according to whether VA or VB is conductive. The voltage across this condenser represents by its sign and magnitude the phase relation between the inputs to A1, B1 and may be applied to actuate a voltmeter or to produce a control action. Condensers 1C, 2C may be connected in the anodegrid cross connections between the valves VA, VB to make the circuit frequency-selective so that a multi-vibrator action occurs wherein. the conduction changes of the valves become automatic at a desired frequency.

Inventors

• 👤 Noel Meyer Rust

Bibliographic Details