3) Ultrahigh SNR technology
In order to catch an ultraweak light, the high-sensitivity and high SNR (Signal to Noise Ratio) optical sensor technologies are required. Generally, SNR is decided almost by the optical sensor itself and the performance of the first-stage amplifier mounted immediately after it. For the sensor of Spectratech OEG-16, the SNR is enhanced to the ultimate by the critically-examined parts and mounting method on the orthodox practice. It demonstrates a sufficient performance to measure the hemoglobin (Hb) changes in the frontal lobe.
As for Spectratech OEG-16H, the performance required for the optical sensor became severe much more, and further high-sensitivity and high SNR were required. A significant improvement in SNR was realized by adopting our own super-high SNR technology that had advanced the spread spectrum light modulation circuits and the sensor circuits. As the result, it is improved by 9 dB in SNR or more in spite of its performance being 2 times in gain, and 8 times in speed compared with SpectratechOEG-16.
Sensor part for Specrtaetch OEG-16H
Sensor part for Spectratech OEG-16
Measurement example of pulse wave signal
(Measurement in frontal lobe, 3cm in distance between light source part and light-receiving part, multichannel measurement, and sampling rate of 0.081sec)
In case of ultrahigh SNR technology not used
(Bandwidth is enough, but SNR is bad)
In case of ultrahigh SNR technology used
(Bandwidth is enough, but SNR is bad)
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