| 摘要 |
PURPOSE: To optimize the conversion of distortion and delay spread depending on a difference from a reception level or the like by selecting a conversion table most suitable for a measured reception level and a measured vehicle velocity. CONSTITUTION: A received phase modulation wave is delay-detected by a delay detection circuit 11 to generate an in-phase detection output I and an orthogonal detection output Q. The generated detection component I or Q is given to a distortion quantity detection circuit 14, from which a distortion D corresponding to a delayed spread S is detected. An output from the distortion quantity detection circuit 14 is fed to a control section 15 with an output from a reception level detection circuit 12 and a vehicle velocity detection circuit 13. Then a conversion circuit 17 in the control section 15 selects a table generated under a condition closest to conditions of a received level L(i) and a vehicle velocity V(k) among plural tables in a conversion table storage section 16 generated in advance based on the level L(i) and the vehicle velocity V(k) as an optimum table and uses the selected table to convert distortion into a delay spread value S. |
