Device and method for processing and measuring properties of a moving rod of material

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 two analysis arrangements, each of the at least two analysis arrangements comprising a single sideband demodulator, a low-pass filter, and an analog to digital converter arranged in series,
• wherein each single sideband demodulator of the at least two analysis arrangements 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;
• wherein each low-pass filter of the at least two analysis arrangements is structured and arranged to pass an output signal of the respective single sideband demodulator with the intermediate frequency fim to the respective analog to digital converter, and to filter out higher frequency signal portions,
• wherein a first of the at least two analysis arrangements is structured and arranged to receive a measurement signal transmitted by the microwave resonator, and a second of the at least two analysis arrangements is structured and arranged to receive a measurement signal reflected by the microwave resonator;
• 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;
• an evaluation device structured and arranged to evaluate output signals of the analog to digital converters;
• and
• wherein the control device comprises another evaluation device structured and arranged to evaluate output signals of the analog to digital converters.

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 two analysis arrangements, each of the at least two analysis arrangements comprising a single sideband demodulator, a low-pass filter, and an analog to digital converter arranged in series,
• wherein each single sideband demodulator of the at least two analysis arrangements 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,
• wherein each low-pass filter of the at least two analysis arrangements is structured and arranged to pass an output signal of the respective single sideband demodulator with the intermediate frequency fim to the respective analog to digital converter and to filter out higher frequency signal portions,
• wherein a first of the at least two analysis arrangements is structured and arranged to receive a measurement signal transmitted by the microwave resonator, and a second of the at least two analysis arrangements is structured and arranged to receive a measurement signal reflected by the microwave resonator;
• 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;
• another analysis arrangement comprising a single sideband demodulator, a low-pass filter, and an analog to digital converter arranged in series,
• wherein the single sideband demodulator of the another analysis arrangement is structured and arranged to receive a decoupled part of a sideband signal via the at least one of the circulator, the insulator, the directional coupler, and the signal divider, and to receive the output frequency f0, and
• wherein the low-pass filter of the another analysis arrangement is structured and arranged to pass an output signal of the respective single sideband demodulator with the intermediate frequency fim to the respective analog to digital converter, and to filter out higher frequency signal portions;
• and
• 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 control device comprises an evaluation device structured and arranged to evaluate output signals of the analog to digital converters.

A method for processing and measuring properties of a moving rod of material of the tobacco processing industry, comprising:

• conveying the rod of material through a microwave resonator;
• generating an output frequency f0;
• modulating the output frequency f0 in a single sideband modulator with an intermediate frequency fim that is less than f0;
• supplying a sideband signal with a sideband frequency f0+fim or f0−fim to the microwave resonator;
• demodulating a signal of the sideband frequency f0+fim or f0−fim at least one of transmitted through and reflected by the microwave resonator in a single sideband demodulator with a signal of the output frequency f0;
• and
• passing a measurement signal portion with the intermediate frequency fim through a low-pass filter to an analog to digital converter, while filtering out higher frequency signal portions;
• controlling the sideband frequency by adjusting the output frequency f0 so that the single sideband frequency tracks a present resonance frequency in the microwave resonator;
• and
• periodically switching the output frequency between two values that are adapted so that the sideband frequency alternatingly lies above and below a resonance maximum or minimum, wherein a same signal amplitude at those frequencies is sought.