| 摘要 |
FIELD: medicine; stomatology. ^ SUBSTANCE: method includes several stages. Preliminary stage implies that total dynamic range of resistance variation is divided into finite indexing (enumerated) number of dynamic subranges according to permissible reduced error of analog-to-digital conversion of measured resistance. Analog-to-digital conversion of measured tissue resistance is performed within found and evaluated subrage by two stages. The first stage implies that analog-to-digital conversion of measure resistance for fixed digit count is carried out bit-by-bit, by successive balancing, starting with high-order digit, referring relevant balancing reference resistive weight to each digit. Analog-to-digital conversion for the rest low-order digits within the same subrange is accompanied with correction of balancing up and down by discrete value corresponding to low-order digit weight. The device for measurement of tooth solid tissue resistance contains electrodes, reference voltage source, null device, low-pass filter, instrumental amplifier and digital measurement device with liquid crystal display. It also comprises reference voltage regulator, electrodes switch keys, resistive bridge, and voltage divider. Digital measurement device with liquid crystal display is designed as microprocessor system including microprocessor with attached keyboard, memory unit and interface scheme RS-232. ^ EFFECT: improved reliability and reproducibility of results at wide spread of rating indices for teeth of any types and for various patients. ^ 4 cl, 2 dwg |
