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Subject: search.filters.subject.Frequency Division Multiplexing

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    Fully Digital Pulse Oximeter Cosine Wave Driven Generate two PPG AMs and AM Synchronous Detector with Single Microcontroller
    (2022-01-01)
    Kainan, Pattana
    ;
    Rungkrae, Manussawee
    ;
    Wiriyatanachit, Supatsara
    ;
    Wardkein, Paramote
    ;
    Lertterada, Krittapas
    In this article, an embedded microcontroller ESP32 implement to be a pulse oximeter is proposed. The almost overall system operates on a microcontroller except for the analog front-end trans-impedance amplifier. The system works by generating two different frequency cosines with cosine function and converting them to be analog cosine signals to drive IR and Red-light sources. The two PPG AM signals are summed in FDM form at the output of the light detector, and it is amplified and converted to be digital signal by the microcontroller after that the digital signal as mentioned above is selected by two digital BPFs with different center frequencies and two PPG AMs are obtained. Two PPG AMs have been demodulated with AM synchronous detector therefore the PPG IR and PPG RED are obtained. They are employed to estimate oxygen saturated and display on OLED along with mobile devices android OS by Bluetooth communication channel. The experiment results show that the proposed system can well operate and have accuracy and precision are 98.1261% and 0.9031, respectively.
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    The analysis of IRBUS channel allocation for decrease four-wave mixing in DWDM system
    (2013-09-18)
    Jumpates, Ashira
    ;
    Srinuan, Chollatee
    ;
    Noppanakeepong, Suthichai
    ;
    Rachnarong, Vissavavit
    ;
    Injoungjirakit, Nainapas
    This paper presents a new model of optical channel allocation named "IRBUS" for improving the operation of a DWDM light source multiplexing by not have to use an optical filter in the DWDM de-multiplexer device. By our method can reduce transmission loss in case of the number of channels are plentiful and each of the channels is nearby that be found in Dense Wavelength Division Multiplexing (DWDM) Systems. The transmission loss is called "Four-Wave Mixing (FWM)" caused by the nonlinearity of the optical fiber signal. The results of numerical computation shown that the IRBUS model can decrease average FWM efficiency from -12.03dBm to -28.27dBm indicated that the remains FWM value are less than other methods and can also reduce the BER probabilities from - 5dBm to -19.75 dBm. © 2013 SPIE.