GB604270A - Improvements in or relating to wave guide frequency changers - Google Patents

Abstract

604,270. Wave-guides. WOOTTON, D. J. Sept. 16, 1943, No. 15240. [Class 40 (v)] An incoming wave and a local wave are combined in a non-linear mixing device shunted across a wave-guide, matching being effected by an adjustable piston closing the end of the guide. The crystal unit 4 is held by screwed elements 10, 11 which slide in a radial hole in a block 12 surrounding the guide 1, and are retained by a spring loop 13. One terminal of the crystal unit thus makes direct contact with the guide wall, the other terminal 14 sliding in a socket 15 which is separated by insulation 17 from the inner conductor 16 of a coaxial line 16, 19 by which the intermediate frequency is taken off. The local wave is introduced by a probe positioned opposite the crystal and directed at right angles to the axis of the crystal element 4. Matching is effected by the adjustment of a screw-actuated plunger 24 closing the end of the guide. The plunger has a quarterwave extension 27 forming with the guide wall a coaxial line which acts as a short-circuit at the point B nearest the crystal. The Specification also describes a wave-guide mixer in which in addition to an adjustable piston in the guide, two other piston adjustments are associated with the crystal mounting (Fig. 1, not shown). The adjustable plunger 24 may be replaced by an adjustable radial probe extending near the face of a fixed plunger. Alternatively, tuning may be effected by a resonant rotatable ring, described in Specification 597,216.