Double-channel moisture meter
A. Tkach, D. Khokhlikhin · 2002
Some aspects of a double-channel moisture meter development and the basics of related signal processing, are considered. There are many methods of moisture metering, but only one method can satisfy following requirements: high accuracy; high speed; and human safety. That is the optical method. To determine moisture by the optical method, a device must measure the light intensity, reflected from the material, on two wavelengths (analytic and reference). The first is the line in the absorption spectrum of the water, the second depends on reflecting properties of material. The main advantage of the double-channel architecture is the use of two optical receivers on analytic and reference wavelengths respectively. Two receivers make possible synchronous and independent processing of the optical signals, but they require calibration because of their parameter difference. A calibration lamp was included in this device to make periodical calibration of these receivers.