Synchronous CDMA telemetry system for use in a wellbore

摘要

A synchronous CDMA telemetry system is provided for use in a wellbore. In one described embodiment, each data bit of digital outputs of multiple downhole data sources is multiplied by an orthogonal code unique to each data source. The resulting encoded outputs are modulated on a carrier frequency and summed on a transmission channel. The resulting signal is demodulated at a remote location and separately multiplied by each of the codes to separate out the contributions to the signal from each data source. The individual demodulated and decoded outputs are then integrated over the length of each data bit.