| 摘要 |
A downhole electromagnetic telemetry system with an increased data rate is disclosed. In one embodiment, a PSK data transmission system is used to transmit data in a downhole electromagnetic telemetry system for Measure While Drilling (MWD) applications. MWD applications suffer from data rates that are not well suited for the ever-increasing amount of data that needs to be transmitted. One method of increasing the data rate includes increasing the carrier frequency, but this can cause undesirable signal attenuation and distortion. Conversely, decreasing the carrier frequency provides the reward of a stronger signal at the risk of aliasing, especially with wide bandwidth signals. A derivation is disclosed predicting that the frequency may actually be decreased while increasing the number of phase states to achieve a higher data rate, without affecting the bandwidth. The system and method disclosed may advantageously provide a robust, low-power electromagnetic telemetry system with an increased data rate. |
