A mid-infrared carbon dioxide (CO2) sensor is presented for the application in greenhouse environment. An integrated multi-pass gas chamber and a dual-channel differential detection method are adopted to decrease response time and suppress envi
A new blind frequency offset estimation method based on cyclic prefix and virtual subcarriers in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is presented. It is able to estimate the fractional part and integral part of fre