| 摘要 |
<p>The bridge circuit, interconnected with a sample box, containing a sample of particulatematerial, is energised by a test signal and provides a bridge output signal whose phase, relative to the phase of the test signal, and whose amplitude are related to the electrical admittance of the sample. After compensation for variations in temperature and bulk density of the sample, the bridge output signal is applied to a first controlled rectifier which is also provided with a reference signal whose frequency is identical to that of the test signal and whose phase is shifted by a predetermined amount from that of the test signal. The first controlled rectifier passes only that component of the bridge output signal in-phase with the test signal to provide a first DC signal related to the measured conductivity of the sample. The bridge output signal is also applied to a second controlled rectifier which is also provided with the reference signal, as coupled through a 90 deg. phase shift circuit.</p> |
