Abstract: Apparatus for ascertaining the mass and/or the moisture content of successive increments of a running rod containing tobacco and/or filter material for tobacco smoke has a resonator housing with a cylindrical internal chamber which is disposed between an inlet and an outlet and wherein the rod is exposed to microwaves. The housing is made of a metallic material having a low thermal expansion coefficient, and its internal surface is lined with gold or another corrosion resistant substance. A protective plastic tube establishes a path for the rod from the inlet, across the chamber and into the outlet of the resonator housing.

Abstract: Apparatus for ascertaining the mass and/or the moisture content of successive increments of a running rod containing tobacco and/or filter material for tobacco smoke has a resonator housing with a cylindrical internal chamber which is disposed between an inlet and an outlet and wherein the rod is exposed to microwaves. The housing is made of a metallic material having a low thermal expansion coefficient, and its internal surface is lined with gold or another corrosion resistant substance. A protective plastic tube establishes a path for the rod from the inlet, across the chamber and into the outlet of the resonator housing.

Abstract: Apparatus for ascertaining the mass and/or the moisture of succesive increments of a running rod containing tobacco and/or filter material for tobacco smoke having a resonator housing with a cylindrical internal chamber which is disposed between and inlet an outlet and wherein the rod is exposed to microwaves. The horsing is made of a metallic material having a low thermal expansion coefficient, and its internal surface is lined with gold or another corrosion resistant substance. A protective plastic tube establishes a path for the rod from the inlet, across the chamber and into the oulet of the resonator housing.

Abstract: The resonance frequency and/or damping of a high-frequency oscillator which contains a variable impedance (such as a capacitor in a moisture detector for coffee or tobacco) is ascertained by generating first signals which denote the envelope curves of oscillations during intervals between successive excitations of the oscillator. Pairs of second signals denoting predetermined portions of envelope curves are transmitted to a dividing circuit, and the quotients of such pairs of second signals are indicative of the damping. Resonance frequency is ascertained by counting the number of oscillations per interval. Oscillations of the oscillator can be rectified prior to the generation of first signals.