Vital-Signs Detector Based on Frequency-Shift Keying Radar

Sensors

Jae Young Sim¹  Jae-Hyun Park¹  Jong-Ryul Yang¹ 

[1] Department of Electronic Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea;

关键词: frequency-shift keying radar;    cross-correlation;    envelope detection;    continuous-wave radar;    frequency discrimination;    vital-signs monitoring;   

DOI  :  10.3390/s20195516

来源: DOAJ

【 摘 要 】

A frequency-shift keying (FSK) radar in the 2.45-GHz band is proposed for highly accurate vital-signs detection. The measurement accuracy of the proposed detector for the heartbeat is increased by using the cross-correlation between the phase differences of signals at two frequencies used by the FSK radar, which alternately transmits and receives the signals with different frequencies. Two frequencies—2.45 and 2.5 GHz—are effectively discriminated by using the envelope detection with the frequency control signal of the signal generator in the output waveform of the FSK radar. The phase difference between transmitted and received signals at each frequency is determined after calibrating the I / Q imbalance and direct-current offset using a data-based imbalance compensation algorithm, the Gram–Schmidt procedure, and the Pratt method. The absolute-distance measurement results for a human being show that the vital signs obtained at each frequency using the proposed FSK radar have a cross-correlation. The heartbeat detection results for the proposed FSK radar at a distance of < 2.4 m indicate a reduction in the error rate and an increase in the signal-to-noise ratio compared with those obtained using a single operating frequency.

【 授权许可】

Unknown