| 摘要 |
PURPOSE:To reduce an error at information signal restoration based on distortion of waveform due to delay spread by weighting to the output of a correlating device before detection by a weighting circuit. CONSTITUTION:The output of a matched filter 8 as a correlation device is branched, one is inputted to a variable gain amplifier 16 and a the other is given to a threshold vlaue detector 18 via an envelope detector 17. The output of the detector 18 is at ''1'' when it exceeds the threshold value and at ''0'' in other cases, and a trigger circuit 19 outputs a trigger pulse at the leading where the output of the detector 18 is transferred from ''0'' to ''1''. This pulse is inputted to a pulse generator 21 via a switch circuit 20 and a pulse having a width slightly shorter than one code length is generated. When this pulse is generated, the generator 21 outputs a signal at the same time, interrupts the switch circuit 20 and continues its state until the pulse is finished. Further, the output pulse is modified 22 into a suitable waveform from a plusive form, a gain control circuit 23 is driven by the output and the gain of the amplifier 16 is changed and weighted. |
