초록 ▼

An oscillator provides an output signal, of frequency f0, whose phase is shifted by substantially 45°to obtain a test signal which is coupled by a first cable to a bridge circuit located in proximity to a sample box and interconnected with an active, center electrode of that sample box. In response

An oscillator provides an output signal, of frequency f0, whose phase is shifted by substantially 45°to obtain a test signal which is coupled by a first cable to a bridge circuit located in proximity to a sample box and interconnected with an active, center electrode of that sample box. In response to the test signal, the bridge circuit provides a bridge output signal whose frequency is identical to that of the test signal and whose phase, relative to that of the test signal, and whose amplitude are related to the electrical admittance of particulate material within the sample box. The oscillator output signal is also applied to a phase-shifting network which provides first, second, third and fourth signals respectively in-phase, 90°out-of-phase, 180°out-of-phase, and 270°out-of-phase with the test signal. A switching circuit couples the first, second, third and fourth signals to its output in a predetermined sequence and at a frequency of fa0 is much greater than fa

대표청구항 ▼

An improved apparatus for use in providing separate measurements of the conductivity and dielectric coefficient of a material, said apparatus comprising: (a) first means for providing a test signal having a predetermined frequency f0; (b) second means responsive to said test signal for providing an

An improved apparatus for use in providing separate measurements of the conductivity and dielectric coefficient of a material, said apparatus comprising: (a) first means for providing a test signal having a predetermined frequency f0; (b) second means responsive to said test signal for providing an output signal whose frequency is identical to that of said test signal and whose phase, relative to that of said test signal, and whose amplitude are related to the measured electrical admittance of said material; (c) third means for providing a reference signal whose frequency is identical to that of said test signal, said third means being adapted to shift the phase of said reference signal at a predetermined frequency fa0 is much greater than fa90°out-of-phase relationship with said test signal; and (d) fourth means for mixing said output signal from said second means and said reference signal to provide an output signal which is successively related to the conductivity and to the dielectric coefficient of said material.