Tobacco moisture content measuring appts. - has microwave signal generator with divider splitting signal onto two signal paths with test capacitor in one, and delay line in other path

摘要

The measuring appts. has a microwave signal generator (20), two signal paths and a signal divider (21) for distribution of the microwave signal onto these two paths. A test capacitor (22) is arranged in the first signal path (15, 16, 2, 3), while the second signal path contains a reference delay device (23). A phase shift detector (28) receives signals from the two paths, and provides an output as a measure for the time shift of the waveform of the signals. Pref. two limiting amplifiers (26, 27) of identical design are provided, each being incorporated in one signal path for direct supply of the signals to the phase shift detector. A second generator (29) may provide a second microwave signal of different frequency, but adjacent to its band. The second signal is mixed (24, 25) with signals from the test capacitor and the reference delay device. The mixer signals are supplied to the phase shift detector via the limiting amplifiers.