NONELECTRIC-QUANTITY-TO-DIGITAL-CODE CONVERTER Russian patent published in 1994 - IPC

FIELD: nonelectric quantity conversion and digital measurement technology. SUBSTANCE: converter has crystal oscillator, two frequency dividers, polarity selector switch, two switches, flip-flop, EXCLUSIVE OR gate, and also input differential amplifier, active band filter, phase-sensitive demodulator, active low-frequency filter, modulator, and feedback resistor, reference-voltage generator, integrator, and comparator. All these components function to shape pulse supply voltage for bridge-type reference-frequency sensor, amplify and narrow-band filter off sensor output signal in narrow band, filter excess noise of amplifier at this frequency, this procedure being followed by phase-sensitive demodulation and filtering, as well as stabilization of amplifier gain by means of negative feedback circuit; then analog-to-digital conversion of mentioned circuit output voltage is made depending on push-pull integration with input value integration duration multiple of double cycle of pulse supply voltage of bridge-type sensor. Measurement result is shaped in pulse counter and upon completion of each measurement transferred to output register. EFFECT: improved resolution and accuracy in measurement of mass, force, pressure, strain, and other quantities due to exclusive random error component caused by excess noise of bridge-type sensor output-signal amplifier from measurement result. 1 dwg