Patent ID: 8912805

Claim:
A device for processing and measuring properties of a moving rod of material of the tobacco processing industry that includes a microwave measurement device comprising: a microwave resonator structured and arranged so that the rod of material is conveyable through the microwave resonator; a microwave generator with an output frequency f0; a frequency stabilized oscillator structured and arranged to generate an intermediate frequency fim that is less than f0; a single sideband modulator structured and arranged to supply the microwave resonator with a sideband signal having a sideband frequency shifted with respect to the output frequency f0 by the intermediate frequency fim; at least one analysis arrangement comprising a single sideband demodulator, a low-pass filter, and an analog to digital converter arranged in series; the single sideband demodulator is coupled to receive a measurement signal of the sideband frequency that is transmitted through or reflected from the microwave resonator, and to receive the output frequency f0; the low-pass filter is structured and arranged to pass an output signal of the single sideband demodulator with the intermediate frequency fim to the analog to digital converter, and to filter out higher frequency signal portions; at least one of an insulator, a circulator, a directional coupler, and a signal divider being disposed between the single sideband modulator and the microwave resonator; a control device structured and arranged to control the output frequency f0 so that the single sideband frequency tracks a present resonance frequency in the microwave resonator; wherein the microwave generator comprises a digital signal generating device structured and arranged to generate the output frequency f0 by direct digital synthesis, and wherein the single sideband modulator comprises an I/Q modulator, the single sideband demodulator comprises an I/Q demodulator supplied with the intermediate frequency fim, and the frequency stabilized oscillator comprises a digital to analog converter structured and arranged to generate two signals shifted from each other by 90° for the intermediate frequency fim; an evaluation device structured and arranged to evaluate output signals of the analog to digital converter; and wherein the control device comprises another evaluation device structured and arranged to evaluate output signals of the analog to digital converter.