GB584250A - Improvements in or relating to apparatus for measuring power and impedance in high frequency transmission lines - Google Patents

Abstract

584,250. Power, voltage, resistance, and reactance meters. CORK, E. C. Sept. 25, 1941, No. 12410. [Class 37] Apparatus for measuring high-frequency power comprises a number of voltage responsive devices spaced apart along the transmission line at a distance apart predetermined in relation to the wavelength of the high-frequency voltages transmitted along the'line in such a manner that an evaluation of the power may be effected by appropriately combining the indications of the devices. Three voltage-responsive devices may be spaced apart by a distance equal to one-eighth of the wavelength of the highfrequency voltage transmitted along the line or any odd integral multiple thereof. Alternatively two voltage-responsive devices may be employed, separated by a quarter of the wavelength. The voltage-responsive devices may be diodes, crystals, or thermo-couples, and are preferably capacity-coupled to the transmission line. For this purpose one of the terminals of each device may be provided with a probe that can be disposed in proximity to one of the conductors of a parallel wire system or can be inserted through an aperture in the outer conductor of a concentric line in proximity to the centre conductor, or through the tubular conductor of a wave guide. The outputs of the voltage-responsive devices may be applied to a cathode-rav tube so that the peak values of the potentials can be observed, from which peak power may be calculated. If the constants of the line and the length of the line between the load and the voltage responsive device nearest the load is known, the resistive and reactive components of the load may be calculated and any mismatch between the line and the load determined. Specifications 584,249 and 584,251 are referred to.