Patent ID: 7483735
Filing Date: 2009-01-27
Classification: A61B,G01G

Abstract:
1. A method for measuring dielectric constant of body tissues under the skin and body impedance based on a method of frequency digital sampling and for evaluating body composition, the method comprising inputting by keyboard a testee's serial number, height, age, gender, and parameter indicating whether or not an athlete; standing a testee with the testee's feet on a measuring platform having a weighing sensor to measure body weight, providing a body weight signal from the weighing sensor to a weighing signal processing circuit; generating oscillating frequency signals related to testee's impedances and dielectric constant of tissues under the skin with a positive feedback RC oscillator circuit and connecting the positive feedback RC oscillator circuit to an MCU system for frequency digital sampling; calculating body fat content and total body water by software of the MCU system, and displaying body weight, body fat content and total body water on the display, wherein said method further comprises: providing body weight signals from the weighing signal processing circuit as frequency signals; connecting the positive feedback RC oscillator circuit with two ends of a capacitance grid sensor to generate an oscillating frequency related to dielectric constant of body tissues under the skin by positioning testee's feet soles to contact the capacitance grid sensor on the measuring platform; connecting the positive feedback RC oscillator circuit with two electrode plates or two groups of electrode plates on the measuring platform, and generating oscillating frequency signals related to body impedance by positioning the testee's feet soles to contact the two electrode plates or two groups of electrode plates within a certain area on the measuring platform; introducing switched capacitors with different capacitance values to said positive feedback RC oscillator circuit and obtaining several oscillating signals with non-fixed different frequencies related to body impedance; inputting body weight frequency signals coming from the weighing signal processing circuit, oscillating frequency signals related to dielectric constant of body tissues under the skin and body impedance signals corresponding to the several oscillating signals with non-fixed different frequencies from the switched capacitors through an I/O interface of the MCU system; calculating from the signals provided to the I/O interface a ratio between intracellular water and total body water through software of the MCU system; and displaying the ratio between intracellular water and total body water.