GB581921A - Improvements in or relating to amplifier gain control systems - Google Patents

Abstract

581,921. Radiolocation. HARDWICK, J. Oct. 10, 1939, No. 27565. [Class 40 (v)] Relates to systems for locating the position of a distant transmitter, or reflecting body, by using two or more receivers separated by a multiple of the working wave-length, as described in Specification 581,920, and consists in a method of equalizing the gain of each of the receivers which is controlled by an automatic volume control voltage which is independent either of the direct or reflected signal. The control voltage may be introduced directly into each of the receivers at predetermined intervals, not covering a complete period of reception of the position-indicating signal. An auxiliary control signal of variable amplitude is separately radiated, the receivers being made sensitive to this auxiliary signal for a part or all of its duration, but not being a complete period of the position-indicating signal. Fig. 1 shows an installation in which a pulse " signal A, Fig. 2, is fed from a generator 16 to the main transmitting aerial 2, and is picked up, after reflection, say from an invisible aeroplane, by three spaced aerials 3, 4, 5 connected to separate receivers 6, 7, 8. A preliminary pulse B, Fig. 2, is fed from the generator 16 to the auxiliary aerial 10, and is also fed direct to the A.V.C. circuits 13, 12, 14 of the respective receivers through a delay network 15. To prevent the receivers from being paralysed by the main outgoing pulse from the aerial 2, a " suppression " pulse C, having the shape and timing (relatively to the pulses A and B) shown in Fig. 2, is also applied from the generator 16 directly through the lead C to the three receivers 6, 7, 8. The A.V.C. circuits may be of the types described in Specifications 497,637 or 512,109. Specification 458,585 also is referred to.