METHOD OF ULTRASONIC SPECTROMETRY WHEN EXAMINING BIOLOGICAL FLUIDS Russian patent published in 2020 - IPC G01N29/36 G01N33/48 

FIELD: spectrometry.

SUBSTANCE: invention can be used for ultrasonic spectrometry when analyzing biological fluids. Essence of the invention consists in the fact that measurement of the resonant frequency and width of the resonant peak of the biological fluid sample is performed in the acoustic cell of the fixed-length ultrasonic spectrometer. Measurement of the resonant frequency of the cell with the analyzed sample is carried out in series with respect to the cell with distilled water, reference signal and signal at the output of acoustic cells are directly digitized, the obtained information in form of an array of acoustic parameters and absorption coefficients is transmitted to a personal computer and processed using software. From the output of the synthesizer, the signal of harmonic oscillations of the specified frequency is supplied to the input of the resonator and simultaneously to the first input of the analogue-to-digital converter (ADC). Process of synchronous sampling of signals from both channels of analogue-to-digital converter is started, characteristics of AFC and PFC are calculated. In the vicinity of the assumed resonance frequency, a frequency grid is formed. Second derivative of phase and dependence approximated by straight line are determined. Using the obtained data, the current resonance frequency and the current width of the resonant peak are determined.

EFFECT: high accuracy and speed of measuring resonant frequency and resonance peak width in fixed-length ultrasonic spectrometers.

1 cl, 2 dwg