OPTICAL MOISTURE METER Russian patent published in 1998 - IPC

FIELD: instrumentation, measurement of moisture content of solid materials. SUBSTANCE: radiation source of optical moisture meter is manufactured in the form of three selective radiators on light-emitting diodes that are modulated from one generator of sinusoidal oscillations with stabilization of amplitude. Radiation source is inserted with phase shifter turning initial phase of oscillations of mentioned generator through 90 deg. Its output is connected to input of first modulator that carries out modulation of first light-emitting diode. Two other light-emitting diodes are modulated by means of second modulator which input is connected directly to output of generator. Meter is also provided with five low-pass filters, two aperiodic amplifiers with constant gain factor Kg=2, four signal multipliers, tuned generator of sinusoidal oscillations and one more 90 deg phase shifter used in ring of phase self-tuning of frequency. EFFECT: increased measurement precision. 1 dwg