GB1344547A - Arrangement for compensating direction finding errors of a twin path cathode ray tube direction finder - Google Patents

Abstract

1344547 Radio direction finders LICENTIA PATENT-VERWALTUNGS-GmbH 4 Aug 1971 [7 Aug 1970] 36661/71 Heading H4D In a twin path cathode ray tube direction finder amplitude or phase compensation for environmental influences on the antennae is provided in the paths which compensation is automatically adjusted as a function of the operating frequency. In a ship-mounted direction finder (DF) the effects of the superstructure are compensated by adjusting the relative gain of the loop channels 2, 3 by amplifiers 5 or attenuators 19 and in the sensing aerial channel by phase shifter 4. Since the directional and phase errors can be predetermined for particular operating conditions and frequencies the compensation is arranged to be automatic. Crossbar unit 16 receives binary coded inputs 14-16 from a frequency counter or an electronic frequency controller representing the operating frequency and band from which it produces sixty control signals 12 depending on the operating conditions. The signals 12 are received by two further cross-bar units 10, 11 which provide output signals 18 for the loop channels 2, 3 and signals 24 which are binary coded at 8 to drive phase shifter 4. The loop channel compensation provides for up to 34 degrees of error either in eighteen equal steps of 2 degrees or in 1 degree steps at lower errors and 3 degrees steps at higher errors. The phase compensator 4 provides 0-360 degrees of compensation in equal steps for 15 degrees from five elements combined in series as dictated by the coded signals 6. The cross-bar unit 13 may utilize soldered or plugged interconnections or may use photo-diodes or transistors and a light source illuminating the unit through a punched card, the card being programmed for particular operating conditions, e.g. loading of the ship.