GB219660A - Improvements in or relating to wireless receiving apparatus - Google Patents

Abstract

219,660. Marconi's Wireless Telegraph Co., Ltd., (Assignees of Bucher, E. E.). July 24, 1923, [Convention date]. Thermionic amplifiers and deteclors. -A sensitive and selective receiver comprises two regenerative circuits A<1>, B<1>, Fig. 1, of which A<1> is directly connected to the aerial system 1 through a variable coil 7, and B<1> is loosely coupled to the aerial through the coils 2, 7 or in any other way. As shown a variable condenser 16 is placed in parallel with the coil 7 of receiver B<1> having an equivalent capacity to that of the aerial 1, so that the tuning adjustments on the two receivers are substantially the same for any given wavelength. The receiver A<1> is first adjusted for maximum signal strength, and the receiver B<1> is then separately adjusted when it is found that reception on the latter is greatly enhanced and becomes highly selective. The receiving circuit B<1> may be replaced by a multivalve set comprising high- and low-frequency amplification with an intermediate detector, as shown in Fig. 3, in which a loop or frame 34 is used both for direct reception and also for coupling to the elevated aerial 1. Alternatively, a second aerial system may supply energy to the receiver B<1>, and may at the same time be coupled to the primary aerial feeding the receiver A<1>. The regenerative action of the two receivers should always be kept in phase, this being ensured by a suitable adjustment of the two input coils.