title: Advanced sine wave modulation of continuous wave laser system for atmospheric CO(2) differential absorption measurements.
abstract: In this theoretical study, modulation techniques are developed to support the Active Sensing of CO2Emissions over Nights, Days, and Seasons (ASCENDS) mission. A continuous wave (CW) lidar system using sine waves modulated by maximum length (ML) pseudo-noise (PN) codes is described for making simultaneous online/offline differential absorption measurements. Amplitude and phase-shift keying (PSK) modulated intensity modulation (IM) carriers, in addition to a hybrid-pulse technique are investigated, which exhibit optimal autocorrelation properties. A method is presented to bandwidth limit the ML sequence based on a filter implemented in terms of Jacobi theta functions, which does not significantly degrade the resolution or introduce sidelobes as a means of reducing aliasing and IM carrier bandwidth.
authors.forename: Joel F
authors.initials: JF
authors.lastname: Campbell
authors.forename: Bing
authors.initials: B
authors.lastname: Lin
authors.forename: Amin R
authors.initials: AR
authors.lastname: Nehrir