Fully Digital Pulse Oximeter Cosine Wave Driven Generate two PPG AMs and AM Synchronous Detector with Single Microcontroller

Pulse Oximetry Based on Quadrature Multiplexing of the Amplitude Modulated Photoplethysmographic Signals

“…Nonetheless, before performing the accuracy comparison with the conventional method, the PPG signal quality of the proposed technique is verified by utilizing the SpO 2 level as a criterion. Since the proposed technique is developed from the method of [14], the SpO 2 values yielded by [14] are thus used as a reference in the PPG signal quality evaluation. This evaluation is performed using the Wilcoxon-Mann-Whitney test as the SpO 2 results obtained from the method of [14] are independent of the SpO 2 results produced by the presented approach [29].…”

“…Recently, the concept of applying AM for calculating SpO 2 , as proposed by Sinchai, S. et al, has been implemented in a commercial device [14]. In their research [14], the pulse oximeter was implemented using a microcontroller, and the carrier signal was digitally generated. This implementation serves as a basis for applying the proposed technique in this research.…”

“…Based on the quadrature multiplexing technique, the proposed system for the pulse oximeter is demonstrated in Figure 4. The implementation of this pulse oximeter is based on the microcontroller, where the technique of [14] is adapted in this article. The realized system, utilizing the microcontroller (ESP32), processes the signal digitally.…”

“…Numerous studies have been conducted to propose techniques aimed at addressing this issue. Examples include techniques based on using filters [1][2][3][4][5][6][7], frequency domain signal processing [8], an independent component analysis [9,10], a Fourier series analysis [11], a time-frequency spectral analysis [12], and modulating techniques [13,14].…”

“…The clean version of the red and IR PPG signals can be retrieved, leading to a higher accuracy in SpO 2 measurement. To validate the commercial feasibility of this principle [13], the concept presented in this work is practically implemented using a microcontroller as proposed by Kainan, P. et al [14]. In the conventional SpO 2 measurement technique, the conventional method uses two out-of-phase driving pulse signals to alternatively drive red and IR light sources [15,16].…”