| 摘要 |
A method and apparatus for determining the attenuation of an RF signal caused by a DPF at an unknown or different ambient temperature than the temperature used for DPF sensor calibration is disclosed. The method and apparatus determine the sensor attenuation just prior to determining the DPF attenuation by disconnecting the antennas and determining the attenuation of a loopback path. This sensor attenuation can then be deducted from the attenuation determined for the normal path that includes the attenuation caused by the loopback path, the cables, and the DPF. This method compensates for variation in the attenuation of the sensor caused by changes in ambient temperature of the sensor. Further temperature compensation is be achieved by determining additional factors to account for variations caused by changes in ambient temperature. |
