| 摘要 |
PURPOSE:To decrease data error rate by changing a loop constant of a PLL at high speed fading in a mobile radio receiver. CONSTITUTION:A radio wave inputted from an antenna 1 is converted into an intermediate frequency and inputted to a data demodulator 7 and carrier detectors 4, 5. The signal is detected at the carrier detector 4 in following to the electric field strength by a high speed fading and changed into a DC voltage. The signal is converted into a DC voltage at the carrier detector 5 corresponding to the average level of the input electric field strength. An output voltage of both detectors 4, 5 are compared for the voltage only when the output voltage of the detector 5 is a set level or over, the output of the comparator 6 is inputted to the data demodulator 7 to vary the loop constant of the PLL. |
